WORKING PAPER Disease Incidence and Mortality Among Older Americans and Europeans Aïda Solé-Auró, Pierre-Carl Michaud, Michael D. Hurd, and Eileen Crimmins RAND Labor & Population WR-1006 July 2013 This paper series made possible by the NIA funded RAND Center for the Study of Aging (P30AG012815) and the NICHD funded RAND Population Research Center (R24HD050906). RAND working papers are intended to share researchers’ latest findings and to solicit informal peer review. They have been approved for circulation by RAND Labor and Population but have not been formally edited or peer reviewed. Unless otherwise indicated, working papers can be quoted and cited without permission of the author, provided the source is clearly referred to as a working paper. RAND’s publications do not necessarily reflect the opinions of its research clients and sponsors. RAND® is a registered trademark. Disease Incidence and Mortality Among Older Americans and Europeans Aïda Solé-Auró INED- Institut National d’Études Démographiques 133 boulevard Davout, 75980 Paris cedex 20 Tel.(33) 01 56 06 43 10 Corresponding author: [email protected] Pierre-Carl Michaud Université du Québec à Montréal & RAND Département des sciences économiques Case postale 8888, Succ. Centre-Ville Montréal, (Québec) CANADA H3C 3P8 Michael Hurd RANDandNBER 1776 Main Street Santa Monica, CA 90407 Eileen Crimmins Andrus Gerontology Center University of Southern California 3715 McClintock Ave, Room 218 Los Angeles, CA 90089-0191 Corresponding author: Aïda Solé-Auró INED- Institut National d’Études Démographiques e-mail: [email protected] Phone number: (33) 01 56 06 43 10 1 Abstract: Recent research has shown a widening gap in life expectancy at age 50 between the U.S. and Europe, as well as large differences in the prevalence of diseases at these ages. Little is known about the processes determining international differences in the prevalence of chronic diseases. Higher prevalence of disease could result from either higher incidence or longer disease-specific survival. This paper uses comparable longitudinal data from 2004 and 2006 for populations aged 50 to 79 from the U.S. and a selected group of European countries to examine age-specific differences in prevalence and incidence of heart disease, stroke, lung disease, diabetes, hypertension, and cancer as well as mortality associated with each disease. Not surprisingly, we find that Americans have higher disease prevalence. However, incidence of most diseases and survival conditional on disease is higher in Europe at older ages, in particular after age 60. The survival advantage in Europe tends to disappear when we control for comorbidities but does not suggest a survival advantage in the U.S. Therefore, the origin of the higher disease prevalence at older ages in the U.S. is to be found in higher incidence and prevalence earlier in the life course. Keywords: disease incidence, disease-specific survival, Europe, United States. 2 Introduction Recent evidence indicates that the prevalence of chronic diseases in old age is higher in the United States (U.S.) than in Europe (Banks et al. 2006; Thorpe et al. 2007; Crimmins et al. 2010b). Americans have also been shown to have lower life expectancy at age 50 than most European countries with the gap growing over time (Glei et al. 2010). The interpretation of higher national levels of disease prevalence in the U.S. is not clear; however, as higher prevalence could result from either higher disease incidence or longer survival with health conditions. The interpretation of the meaning of the differences would be very different depending upon the underlying processes that prevail. Little research has decomposed prevalence at older ages into these components across countries and by age groups. Cause specific mortality rates show that differences in heart disease mortality account for about half of the differential between the U.S. and other high mortality countries, differences in mortality due to diabetes also account for some of the differences. On the other hand, the U.S. does better in cancer mortality (Glei et al. 2010). However, the overall differences in mortality rates by cause do not provide information on how the relative likelihood of dying differs across countries among those with specific conditions because the rates are relative to the total population and thus overall mortality differences by country do not give a complete picture of the dynamics involved. Another important shortcoming of using mortality and prevalence data to understand health processes is the effect of heterogeneity or selection. For example, incidence rates could be invariant with age but differ across individuals. Because disease incidence is positively related to 3 mortality, average incidence rates of survivors would decrease with age, creating a spurious negative age pattern. Omitting heterogeneity biases inferences on the age pattern of incidence and mortality rates because of the potential dynamic selection of the fittest or less risk-prone groups over time (Manton et al. 1986). If the selection process differs across countries, incorrect inferences could be drawn from differences in average incidence and mortality rates. Another important consequence of heterogeneity is that if disease incidence varies with age differentially across countries, it is possible to observe a negative relationship between current disease prevalence and incidence across countries. If the frailty distribution is the same across countries but incidence rates are higher in one country than another, the remaining pool of undiagnosed individuals will be at higher risk in the low incidence country compared to the high incidence country. This is one of the explanations for why the U.S. may have a survival advantage past age 80 relative to European countries (Manton and Vaupel 1995) or why there is mortality crossover by race in the U.S. at older ages (Lynch et al. 2003). Evidence on differences in incidence is scarce, in part because of lack of comparable longitudinal data across countries. Aggregate computation of incidence rates from prevalence by age is complicated by the fact that individuals can have several diseases. One exception is Banks et al. (2010) who compare the U.S. and England, and find generally higher disease incidence rates post age 50 for Americans, caused not only by higher past cumulative disease risk, but also higher new onset of diseases and higher survival. However, it is unclear whether these patterns hold in other European countries where even larger prevalence differences are observed. Furthermore, the comparisons of incidence in Banks et al. (2010) focus on aggregate differences across age groups. In light of potential differences in conditional incidence and mortality rates, we investigate whether aggregate differences are still observed when we control for selection. 4 This paper uses longitudinal data for populations aged 50 to 79 for the U.S. and five European countries to examine age-specific differences in disease incidence and disease-specific mortality from 2004 to 2006. We focus on the most common and frequent health conditions, which are major causes of mortality at older ages: heart disease, stroke, lung disease, diabetes, hypertension, and cancer. We investigate incidence of these conditions using survival models and include indicators of socio-demographic factors and health behaviors to determine how these factors relate to disease onset and how differences affect the differences between Europe and the U.S. We then investigate survival conditional on the presence of these conditions. DataandMethods This analysis uses two longitudinal datasets designed to be comparable: the Health and Retirement Study (HRS) and the Survey of Health, Ageing and Retirement in Europe (SHARE) collected in 2004 and 2006 for individuals aged 50 to 79. HRS is an ongoing longitudinal survey of the U.S. population age 50+ begun in 1992 and regularly refreshed at younger ages with new cohorts.1 SHARE began collecting data in 2004 on the age 50+ non-institutionalized population with a target sample size of 2,000 respondents per country for 12 European countries. In our analysis we use a subset of five countries: Denmark, France, Italy, the Netherlands, and Spain. We focus on those countries because of their relatively high response rate in the SHARE baseline 1 The original sampling frame for each entering HRS cohort is the non-institutionalized population; however, respondents who moved to nursing homes are retained in the sample (HRS, 2011). We eliminated nursing home residents in order to be comparable to the SHARE sample. 5 interview and of a close match between country-specific life table mortality and observed mortality between waves 1 and 2 of SHARE. We will refer to these five countries as “Europe.”2 For both the U.S. and Europe we use 2004 as the base year and examine health transitions occurring in the interval between the initial interview and re-interview in 2006. Table 1 shows the national sample sizes for those aged 50-79 in 2004 and indicates the 2006 interview status of 2004 respondents: interviewed, died, or lost to follow-up. Sample size in 2004 was more than 16,000 individuals in the U.S. and over 11,000 individuals in Europe (Table 1). The HRS response rate is higher at follow-up in 2006. We discuss further the issues of non-response and evaluate the completeness of mortality information below. The number of known deaths between the two waves is higher for HRS (2.9%) than for SHARE (2.0%). Analyses are weighted using sample weights. [Insert Table 1 about here] Evaluation of Mortality Reports and Effect of Differential Response Rates We compared mortality rates estimated from survey data to life-table mortality rates calculated from the Human Mortality Database (HMD) data for 2004.3 Two-year mortality rates from the life-tables weighted by gender are computed to match the average time interval between interviews. Results indicate that survey estimates are relatively close to the life table estimates between ages of 50 and age 80 for the U.S., the Netherlands, Spain, Italy, France and Denmark 2 Almost none of the SHARE respondents are living in nursing homes; we eliminate the small numbers who are. For most of the sample, records are matched to the National Death Index for identification of deaths; in addition, deaths are reported in exit interviews. 3 For most of the HRS sample, records are matched to the National Death Index for identification of deaths; in addition, deaths are reported in exit interviews. In the SHARE data, deaths are reported by survivors in exit interviews. 6 and that these countries represent well the entire set of SHARE countries in terms of life expectancy (see appendix). Mortality above age 80 estimated from the survey is somewhat lower than that in the life tables.4 For this reason, we limit our analysis to the age-range 50-79. Figure 1 shows 2-year mortality rates in the U.S. and in the pooled 5 European countries (weighted by population size) from both the surveys and the HMD. The survey estimates for the U.S. are close to, but slightly higher, than the life table death rates at all ages while the European survey estimates are slightly below the life table estimate. There are multiple reasons why this is the case. SHARE is a new survey; while the HRS is a long-running longitudinal survey. Respondents die on average a year after the initial survey date, so people who are already very ill may not enter the initial wave of a survey but if the survey is long running, they may be more likely to be included.5 Because few people are in nursing homes prior to age 80, and our analysis is limited to those 50-79, this difference in population coverage is not likely to explain the higher mortality risk in the U.S.6 [Insert Figure 1 around here] Non-response is an issue in all longitudinal surveys and, as indicated above, is higher in SHARE than in HRS (about 5.6% lost to follow-up in HRS versus 34% in the 5 SHARE countries). The fact that mortality tracks life-tables relatively well shows that follow-up differences are unlikely to explain the mortality differences we find. However, differential attrition could still have an effect on incidence rates. We have analyzed the determinants of nonresponse in SHARE and developed weights for non-response, which we compared to the weights 4 This discrepancy at older ages is likely due to the exclusion of nursing home residents. Adams et al. (2003) show that the match to life-table mortality for older HRS respondents (age 70+ in 1993) improves in later waves after the first follow-up. 6 In 2004, the fraction of the population in a nursing home between age 50 and 80 in the U.S. is 0.8%. The mortality rate between interviews from 2004 to 2006 interview was 37% for nursing home residents compared to 3.2% for the non-nursing home population. The actual aggregate mortality rate is 3.5% so the inclusion of the nursing home population would add 0.3% to the aggregate mortality rate for this age group. 5 7 provided with the survey data. We conclude that differential non-response is accounted for in the SHARE weights and unlikely to bias the inferences we make on the two populations (for more details, see appendix). Measuring Incidence of Disease Disease presence in both SHARE and HRS is based on self-reports of major chronic conditions: heart disease, stroke, lung disease, diabetes, hypertension, and cancer. The surveys were specifically designed to harmonize their instruments so that in most cases, questions were worded identically. Information on the presence of six diseases is reported in response to the question: “Has a doctor ever told you that you had any of the following conditions? Each condition is then asked about separately. It is hard to determine how diagnostic and reporting differences could affect national differences, but Banks et al. (2006) showed that differences in self-reports of disease between England and the U.S are not driven by differences in reporting. They show that the differences are generally confirmed by biomarkers when self-reports and relevant biomarkers can be compared. For cancer, more aggressive diagnostic procedures in the U.S. might explain some of the higher prevalence observed in the U.S. (Crimmins et al. 2010b). While the initial assessment of disease presence was identical in HRS and SHARE, follow-up questions and procedures differed somewhat. In the 2006 HRS, responses provided at earlier waves about disease presence are pre-loaded. Those who did not have a condition in the previous wave were asked has a “doctor ever told you” you have a disease; a positive response is used to construct our measure of incidence. Those who previously said that they had a condition were reminded of this at the 2006 interview. Sometimes people deny that they have reported the 8 presence of disease. People who denied having a condition in the past were then asked about their present state and they were retroactively recoded as not previously having the disease at the earlier wave. This could lower U.S. incidence rates relative to European ones if these false positives are corrected as in 2006 SHARE did not allow respondents to dispute a condition reported in 2004. Respondents in SHARE who did not have a condition in 2004 were asked in 2006 “has a doctor ever told you that you had/do you currently have any of these conditions? With this we mean that a doctor has told you that you have this condition and that you are either currently being treated for or bothered by this condition”. On one hand, this additional condition of being either treated or bothered could deflate the number of incident cases as respondents who had a condition which does not bother them and for which they are not being treated will be counted as undiagnosed. However, since new conditions are likely to be treated and bother the respondent, it is unlikely to affect the numerator of incidence rates very significantly. However, this difference in wording would tend to lower SHARE incidence rates relative to HRS incidence rates. Overall, denials in HRS and the additional requirement of being bothered/treated in SHARE have opposite effects on the gap between SHARE and HRS incidence rates. Other Variables Because selection may affect the age patterns of survival and incidence we uncover, we control for socio-demographic characteristics and health behaviors in most of the analysis. Sociodemographic controls for age, gender and education are included. The education variable is constructed as: less than some college (13 or less years of schooling) and some college or more 9 (more than 13 years of schooling). We also include measures of overweight and smoking in our regression analyses. Smoking is self-reported as being a former smoker, current smoker, or never smoker. Weight classes are determined using self-reports of height and weight provided in both surveys. These are converted into body mass index (BMI) and classified into two groups: class II obesity and higher (>=35), and those with lower BMI. While weight is notorious for being underreported and height is overestimated by older respondents (Burkhauser and Cawley 2008), Michaud et al. (2007) note there is no indication that biases are different across countries meaning that even if there is an underestimation of obesity rates, the relative ranking of countries is likely to remain unaffected. We use this high level of obesity in or regressions as mortality risk is higher at this level of obesity (Alley et al. 2010). Methods We first examine descriptive data on prevalence and incidence of diseases and mortality by age groups in Europe and the U.S. Then we examine two-year disease incidence rates among those who did not have each condition at the initial interview. We estimate incidence using hazard models for each of the six diseases using a set of pooled samples for the U.S. and Europe for those without specified diseases at the initial interview. Model 1 includes an indication of being in the European sample and controls for age and gender; health behaviors and education are then added to the model (model 2). The Weibull distribution is used for age in these analyses to address the non-monotonic pattern of onset with age observed in the descriptive data. This approach allows us to determine whether there are differences between Europe and the US in 10 incidence rates and whether these are eliminated or reduced when health behaviors and education are controlled. To study differences in mortality rates by disease across countries, we estimate survival models pooling U.S. and European data for those with specified diseases at the initial interview. Four models are presented: Model 1 includes an indicator of being in the European sample and controls for age and gender; Model 2 adds controls for college education; Model 3 adds controls for health behaviors; and model 4 adds controls for co-morbidities from each of the other conditions. In estimating the survival models, we take account of right-censoring as well as differential exposure time between interviews. Although average time between interviews does not vary much between the U.S. and Europe there is considerable heterogeneity within countries. Weights are used in estimating the models. All analyses are conducted using STATA statistical software version 12.0. Results Prevalence and Incidence We document differences in the prevalence of diseases and also obesity for the entire sample aged 50-79 in Figure 2. As expected, the prevalences of disease and obesity are significantly higher in the U.S. than in Europe for each of these conditions. Close to one fifth (18.3%) of Americans have heart disease in this age range compared to one-tenth (10.4%) of the Europeans. Prevalence of most conditions is between 40% and 100% higher in the U.S. compared to Europe. [Insert Figure 2 here] 11 In Table 2, we show the prevalence of disease in the age range 50-54 as well as incidence rates in five age groups from 50 to 79 for individual diseases and obesity in the U.S. and Europe. Focusing first on the prevalence at the initial age group in our sample, we observe that levels are consistently higher for the U.S. and that the differences are large for most conditions at age 50. The differences are smaller for stroke, lung conditions and cancer. This clarifies that part of the difference in disease prevalence at older ages begins at ages well before age 50. [Insert Table 2 here] A review of age specific incidence rates in Table 2 and Figure 3 shows that incidence rates for many conditions post age 50 are worse in Europe. In fact, overall incidence levels for the diseases are higher in Europe. For example, average incidence of heart disease in Europe post age 50 is 4.47% compared to 3.91% in the U.S. Stratifying by age shows that incidence rates are significantly higher in Europe after age 60 for many causes. For several conditions, the differences increase with age. This is the case of lung disease, diabetes, hypertension and to some extent for stroke. This provides evidence of an initial delay in the age at onset of these conditions in Europe; but then acceleration in onset at later ages. On the other hand, incidence rates for cancer are higher in the U.S. than in Europe post age 50. We have reason to believe that this is related to more cancer screening in the U.S., particularly at older ages (Crimmins et al. 2010a). As expected, the incidence rate for obesity is higher in the U.S. than in Europe at all ages. [Insert Figure 3 here] Part of the story for these differences in age patterns of disease may have to do with unobserved frailty in the population at risk. As the prevalence of a condition increases, the undiagnosed population is composed of more people with less inherent risk for the condition, as those most susceptible have had earlier incidence. Since, the U.S. prevalence is higher at the 12 earlier ages, the undiagnosed population in the U.S. at older ages may be less at risk than the undiagnosed population in Europe. This may lead to a negative relationship between prevalence and incidence. Because aggregate age patterns can be misleading due to selection, we analyze survival models which control for socio-demographic and health behavior differences. We assume the dependence on age is captured by a Weibull form7. Adjusting for demographic status, the onset of lung disease and hypertension is higher for Europeans compared to the U.S; the onset of diabetes and cancer is lower in Europe than in the U.S.; and there are no significant differences in the onset of heart disease and stroke between Europe and the U.S. (model 1). There is a positive relationship with age and the onset of all conditions. Males are also more likely to experience the onset of most conditions. [Insert Table 3 here] When having some college education and health behaviors are added to the model (model 2), Europeans only have significantly higher onset of lung disease; they have lower onset of heart disease and cancer; and there are no significant differences between Europe and the U.S. in the onset of stroke, diabetes, and hypertension. This means that the lower incidence of diabetes and the higher incidence of hypertension among Europeans without these controls is linked to the educational and behavioral compositions of the populations. Significant higher disease onset for males persists for heart disease, stroke, diabetes and cancer; and appears for hypertension. Having some college education is negatively related to the onset of lung disease, diabetes and hypertension. 7 An age parameter greater than 2 indicates a rising age profile; a parameter between 1 and 2 indicates a positive relationship with age; and if the parameter less than one there is a negative relationship with age. 13 Former and current smokers have a significantly higher likelihood of lung disease onset. Being a current smoker is related to a higher likelihood of cancer. The effect of obesity on the risk of onset for heart disease, lung disease, diabetes, hypertension, and cancer is strong. Mortality We now focus on mortality among those with diseases. Indeed, if individuals with a condition survive longer in one country compared to another, prevalence may be higher without higher incidence of disease. We report the proportion dying by age among those with each of the six diseases at the initial interview in Table 4: heart disease, stroke, lung disease, diabetes, hypertension, and cancer. We examine the significance of the difference in mortality by age between Europe and the U.S. We then compute the ratio of the mortality rate for those with a condition in the U.S. divided by the mortality rate for those with a condition in Europe. For all diseases, we find higher mortality risks in the U.S. than Europe. For stroke, lung disease, diabetes, and hypertension the ratio is highest at age 50-59 indicating that the mortality differences are greater in younger old age. [Insert Table 4 here] The mortality differences may be at least partly explained by the fact that Americans are more likely than Europeans to have multiple chronic diseases (Crimmins et al. 2010b); that Americans are more obese; and have a different smoking history. In order to test the possibility that these factors explain the differences in mortality from individual diseases, we estimate survival models with a Gompertz specification among those with each disease using a pooled sample of Americans and Europeans. After the initial model which includes age, sex, and being in the 14 European sample, sequential models control for education, current and past smoking experience, obesity, and the prevalence of each of the other five health conditions (Table 5). [Insert Table 5 here] The relative risk of mortality for respondents with four diseases - heart disease, lung disease, diabetes, and hypertension - is significantly lower in Europe than the U.S. controlling for age and gender (Table 5, Model 1). For stroke and cancer there is no significant difference in the relative risk of mortality between Europe and the U.S. Controls for higher education reduce the size of the difference between Europe and the U.S. in mortality risk among those with hypertension, but the difference remains significant. The size of the mortality differences for those with other conditions does not change much with education controls (Table 5, Model 2). When health behaviors are introduced in model 3, the size of the coefficients indicating the effect of being in the European sample are increased substantially meaning that if Americans and Europeans were alike in smoking and obesity, Europe would have even lower relative mortality from all diseases, except cancer. Finally, our last model adds controls for co-morbidity from other health conditions. With these controls, the significance of the mortality differences between Europe and the U.S. vanishes for stroke, lung disease, and diabetes. For heart disease and hypertension the risk of mortality remains significantly lower in Europe than in the U.S., but the size of the difference is halved. This indicates that much of the higher mortality from disease in the U.S. comes from the complications of co-morbidity. Discussion 15 Our results reaffirm that disease prevalence is significantly higher in the U.S. than in Europe, and that this difference begins well before age 50. Higher American prevalence in late middle age is particularly large for heart disease, diabetes, hypertension and obesity. Overall incidence rates for the diseases are higher in Europe; however, when age-stratified incidence is examined, significantly higher incidences in Europe are found for many conditions after age 60. Age specific incidence of diabetes, lung disease and hypertension are generally higher in Europe, with the exception of diabetes at younger old ages. This may indicate that Americans have a different age patterning of chronic conditions with onset of chronic conditions earlier in the life cycle. This may be related to the high levels of obesity and past smoking. It is possible that after the younger old ages those most susceptible to the condition have been eliminated from the risk group and the undiagnosed population in the U.S. at older ages may be at less risk than the undiagnosed population in Europe. On the other hand, the higher prevalence of cancer and obesity in the U.S. is accompanied by higher incidence at all ages. As we have indicated, cancer screening is very different in the U.S. and Europe, especially at older ages (Garcia and Crimmins 2013). Documenting higher incidence of obesity across the ages for the U.S. is an important addition to our knowledge of the process leading the U.S. to rank as one of the most obese countries internationally (Alley et al. 2010). Where there are significant differences in incidence of heart disease and stroke, Europeans have higher incidence. While the incidence of these conditions is much more similar between Europe and the U.S. than for the other conditions; the pattern of slightly higher incidence for the U.S. at younger ages and somewhat higher incidence for Europeans at older ages is also seen in these conditions. When the determinants of disease incidence are estimated using survival models, there are some changes in the differences observed for the U.S. and Europe. We should note that our findings differ from Banks et al. (2010) who found higher disease incidence to be higher among Americans compared to persons 16 in England; however, other examinations of differences across countries have found health among the English to be more similar to that of Americans than that of continental Europeans (Crimmins et al. 2010a). We found higher mortality rates in the U.S. for stroke, lung disease, diabetes, and hypertension at younger old ages (50-59). Americans with most diseases have higher mortality; however, the higher mortality from a number of conditions disappears when the higher comorbidity of American is controlled. What remains is higher American mortality among those who have hypertension and heart disease. Heart disease mortality is the major cause of the European-American differential in life expectancy at age 50, and we are not able to explain the higher mortality of Americans from heart disease by differences in co-morbidity, education, or health behaviors. One motivation for studying disease incidence was to examine the contributions to greater prevalence of disease at older ages in the U.S.: initial conditions (disease at age 50), incidence between age 50 and those older ages, and survival conditional on having the disease. However, at least qualitatively, the relationships among initial conditions, incidence, survival and subsequent prevalence are not coherent. Table 6 summarizes data from Tables 2 and 4 and Figure 2 for six diseases. Consider, for example, heart disease. At age ages 50-54 prevalence in the U.S. and Europe is about nine and four percent respectively. Incidence in the U.S. is lower in the age range 50-79 which should lead to a reduction in the prevalence gap. Mortality conditional on having heart disease is higher in the U.S. which should also reduce the gap. Yet, prevalence age 50-79 in the U.S. is about twice as high as prevalence in Europe. The relationship between prevalence, incidence and mortality is approximately the same for the other five diseases.8 One possible explanation is that the processes are not stationary: there may be cohort effects in 8 We have verified this lack of coherence quantitatively via simulation. 17 prevalence at age 50 and variation over time in both incidence and survival conditional on disease. If this is the case, it has important implications for studying the effect of policy on health: past policy and past population characteristics influenced past incidence in a way that is not observed in current incidence. Thus the relationship between current prevalence and current policy is mediated in a complex manner by historical variation in incidence. [Insert Table 6 here] We can use the observed prevalence rates for people in their 50s and simulate what would happen to the population prevalence of disease in Europe and the U.S. by age 75 assuming the observed incidence and the observed mortality. The implication of the calculations is that the U.S. would continue to have a higher prevalence of heart disease and cancer at older ages; however, Europe would exceed the U.S. by age 75 in diabetes, stroke, and hypertension. Europe would exceed the U.S. in the prevalence of lung disease by age 65. The difference in lung disease is not surprising given the different cohort patterns of smoking; and it is possible that the other implied changes result from the timing of both smoking changes and other cohort changes such as obesity. There are some limitations in the present analysis that could affect our findings. SHARE under-estimates population mortality, whereas HRS mortality is very close to life table mortality. SHARE is a new survey: people who are already very ill, and have an elevated likelihood of dying between the first two waves, may not enter the initial wave of a survey. The HRS is a long-running longitudinal survey so the very ill are more likely to be included. Adams et al. (2003) show that the match to life-table mortality for older HRS respondents (age 70+ in 1993) improves in later waves after the first follow-up. Because people who are already very ill may not enter the initial wave of a survey, but will be there if the survey is long running, the level of disease and mortality in SHARE might be lower than would be true with the unhealthy fully 18 represented. If survey mortality rates were higher and closer to the life table mortality rates for the European population, survival rates conditional on having a disease would be higher and closer to those in the U.S. Additionally, because SHARE respondents who were neither bothered nor treated for a condition may have failed to report it, incidence in SHARE might have been even higher than we observed. Because we do not consider the nursing home population, our results do not reflect the entire population. The nursing home population in both the United States and in Europe would contain persons with relatively high risk of mortality and morbidity. Nursing home residence is generally relatively low in these countries at ages less than 80. While it is often hard to find data on nursing home population by age, in the HRS the nursing home population is 0.8% of the sample at ages 50-80. In Europe estimates for this age range are not readily available. Estimates among those in similar age ranges indicate relatively low nursing home usage for two of our countries: the Netherlands (2% of those 65-80) and Denmark (1% of persons 60-79). Usage appears somewhat higher for France (6% for those 65-80). In the entire 65+ population nursing home usage is low in Italy (2%) and higher in Spain (5.8%). In the U.S. the percentage in nursing homes in the total 65+ population is 5% (http://www.cdc.gov/HomeandRecreationalSafety/Falls/nursing.html). We believe that because the percentages in nursing homes are relatively similar in Europe and the U.S. differential use of nursing homes is unlikely to influence the differences we observe. The combination of effects from these data issues might result in a slight increase of the prevalence rates for the European population; however, it is unlikely that this would be sufficient to change the direction of our findings. In addition, we used data for a relatively short time interval from both surveys. Using data for more waves over a longer time interval would add stability to some estimates, and would verify the direction of our estimates. 19 While we recognize these limitations, the analysis presented here is an important first step in understanding the complex health and survival differences between Europe and the U.S. Overall, the higher prevalence of health conditions in the U.S. does not result from a higher incidence of diseases across the age range; and where there are differences in incidence, they are sometimes explained by compositional differences. Higher American prevalence does not result from higher survival with disease as mortality among those with disease is higher in the U.S. than Europe. The need to study mortality within individual persons rather than by disease is emphasized by the fact that higher American mortality among those with disease is partly explained by the higher comorbidities of Americans. 20 Acknowledgements The authors acknowledge funding from NIA R01 AG040176-02, funding provided from the Spanish Ministry of Science and Innovation (ECO2010-21787-C03-01), and the Beatriu de Pinós grant 2010-2012. An earlier version of this paper was presented at the annual meeting of the Population Association of America, held in San Francisco, May 3-5, 2012. The SHARE data collection has been primarily funded by the European Commission through the 5th framework program (project QLK6-CT-2001-00360 in the thematic program Quality of Life). Further support by the European Commission through the 6th framework program (projects SHARE-I3, RII-CT-2006-062193, as an Integrated Infrastructure Initiative, COMPARE, CIT5-CT-2005028857, as a project in Priority 7, Citizens and Governance in a Knowledge Based Society, and SHARE-LIFE (CIT4-CT-2006-028812)) and through the 7th framework program (SHAREPREP (No 211909) and SHARE-LEAP (No 227822)) is gratefully acknowledged. Substantial cofunding for add-ons such as the intensive training program for SHARE interviewers came from the U.S. National Institute on Aging (U01 AG09740-13S2, P01 AG005842, P01 AG08291, P30 AG12815, R21 AG025169, Y1-AG-4553-01, IAG BSR06-11 and OGHA 04-064). Support for the HRS data collection was primarily provided by the National Institute on Aging (U01 AG009740). 21 References Adams, P., Hurd, M. D., McFadden, D., Merrill, A., & Ribeiro, T. (2003). Healthy, wealthy, and wise? Tests for direct causal paths between health and socioeconomic status. Journal of Econometrics, 112(1), 3-56. Alley, D., Lloyd, J., & Shardell, M. (2010). Can Obesity Account for cross-national differences in Life Expectancy trends? In E. M. Crimmins, S. H. Preston, & B. Cohen (Eds.), International Differences in Mortality at Older Ages: Dimensions and Sources. : Panel on Understanding Divergent Trends in Longevity in High-Income Countries National Research Counci. The National Academies Press. Banks, J., Marmot, M., Oldfield, Z., & Smith, J. P. (2006). Disease and disadvantage in the united states and in england. JAMA: The Journal of the American Medical Association, 295(17), 2037-2045, doi:10.1001/jama.295.17.2037. Banks, J., Muriel, A., & Smith, J. P. (2010). Disease prevalence, disease incidence, and mortality in the United States and in England. Demography, 47, 211-231. Burkhauser, R. V., & Cawley, J. (2008). Beyond BMI: The value of more accurate measures of fatness and obesity in social science research. Journal of Health Economics, 27(2), 519529, doi:10.1016/j.jhealeco.2007.05.005. Crimmins, E. M., Garcia, K., & Kim, J. K. (2010a). Are International Differences in Health Similar to International Differences in Life-Expectancy?,. In E. M. Crimmins, S. H. Preston, & B. Cohen (Eds.), International differences in mortality at older ages: Dimensions and Sources. . Washington, DC: Panel on Understanding Divergent Trends in Longevity in High-Income Countries. The National Academies Press. Crimmins, E. M., Preston, S. H., & Cohen, B. (2010b). International differences in mortality at older ages: dimensions and sources. Washington, DC: National Academies Press. Glei, D. A., Meslé, F., & Vallin, J. (2010). Diverging Trends in Life Expectancy at Age 50: A Look at Causes of Death. In E. M. Crimmins, S. H. Preston, & B. Cohen (Eds.): In International Differences in Mortality at Older Ages:Dimensions and Sources. Panel on Understanding Divergent Trends in Longevity in High-Income Countries National Research Council. The National Academies Press. Lynch, S. M., Brown, J. S., & Harmsen, K. G. (2003). Black-White Differences in Mortality Compression and Deceleration and the Mortality Crossover Reconsidered. Res Aging, 25(5), 456-483. Manton, K. G., Stallard, E., & Vaupel, J. W. (1986). Alternative Models for the Heterogeneity of Mortality Risks Among the Aged. Journal of the American Statistical Association, 81(395), 635-644. Manton, K. G., & Vaupel, J. W. (1995). Survival after the Age of 80 in the United States, Sweden, France, England, and Japan. New England Journal of Medicine, 333(18), 12321235, doi:10.1056/nejm199511023331824. Michaud, P.-C., Kapteyn, A., Smith, J. P., & van Soest, A. (2011). Temporary and permanent unit non-response in follow-up interviews of the Health and Retirement Study. Longitudinal and Life Course Studies vol.2 (2011) nr.2 p.145-169. Michaud, P.-C., Soest, A. v., & Andreyeva, T. (2007). Cross-country variation in obesity patterns among older Americans and Europeans. Program for Research on, Social Economic Dimensions of an Aging, Population. 22 Thorpe, K. E., Howard, D. H., & Galactionova, K. (2007). Differences in disease prevalence as a source of the U.S.-European health care spending gap. Health affairs (Project Hope), 26(6). 23 Tables Table 1: Sample sizes (2004) and Respondent Status (2006) in 5 European Countries (SHARE) and the U.S. (HRS); ages 50-79. Country N (2004) Denmark France Italy Netherlands Spain Total European Countries United States Total 1,428 2,697 2,323 2,619 2,059 11,126 15,890 27,016 % Responded (2006) 74.8 63.2 68.1 63.1 57.7 64.0 91.5 79.6 Died % Died % Lost 36 52 38 45 48 219 529 748 2.4 1.9 1.8 1.7 2.4 2.0 2.9 2.5 22.8 34.9 30.2 35.2 39.9 34.0 5.6 17.9 Source: SHARE and HRS 2004, 2006. 24 Table 2: Prevalence and Incidence by Age in the U.S. (HRS) and 5 European Countries (SHARE). Individuals aged 50-79 Panel A: U.S. Prevalence Age 50-54 and Incidence rates by age Heart disease Stroke Lung Disease Diabetes Hypertension Cancer AGE 9.02 2.21 4.98 11.04 32.71 4.85 Prevalence 50-54 2,812 2,812 2,812 2,812 2,808 2,811 N 50-54 Incidence 50-54 2.18 0.65 1.04 3.07 8.11 1.24 55-59 3.30 0.93 1.59 3.99 9.65 1.99 60-64 3.89 0.80 1.73 4.27 11.71 2.63 65-69 5.03 1.22 1.57 3.60 11.49 3.20 70-74 5.33 2.56 2.06 3.19 12.28 3.37 75-79 7.24 3.16 2.71 3.08 11.44 4.20 Total Incidence 3.91 1.28 1.65 3.59 10.18 2.45 (50-79) HRS N 50-79 11,559 13,604 13,263 11,939 7,053 12,801 Panel B: 5 Country European Prevalence Age 50-54 and Incidence rates by age Heart disease Stroke Lung Disease Diabetes Hypertension Cancer AGE Prevalence 50-54 4.31 1.19 3.31 5.11 18.00 3.34 1,848 1,848 1,848 1,848 1,848 1,848 N Incidence 50-54 1.81 0.61 1.55 3.46 9.61 0.64 55-59 2.09 0.81 2.51 3.33 13.32 1.54 60-64 5.06 0.93 3.90 4.16 17.00 1.48 65-69 5.80 1.66 3.46 4.94 17.67 1.84 70-74 9.0 3.35 6.40 4.83 24.12 1.85 75-79 6.43 4.36 5.81 5.48 19.42 2.64 Total Incidence (50-79) SHARE 4.47 1.65 3.57 4.16 15.51 1.55 N 50-79 6,417 6,929 6,702 6,456 4,911 6,783 Obese >=35 14.06 2,808 2.78 3.23 2.85 3.18 1.57 0.84 2.59 12,675 Obese >=35 6.02 1,878 1.70 1.37 1.39 1.32 1.31 0.94 1.38 6,723 Source: HRS 2004 - 2006. HRS weights are used in this table. SHARE, 2004 – 2006. SHARE weights are used in this table. Europe includes: Denmark, France, Italy, the Netherlands, and Spain. The significance of differences is shown in Figure 3. 25 Table 3: Disease Incidence Model Estimates. Individuals aged 50-79. Heart disease Model 1 Model 2 Socio-demographic Europe Age Male College Health behaviors Former smoker Current smoker BMI>35 Constant Socio-demographic Europe Age Male College Health behaviors Former smoker Current smoker BMI>35 Constant -0.09 1.57 *** 0.22 *** -0.17 * 1.66 *** 0.17 ** -0.10 Stroke Model 1 Model 2 -0.05 1.69 *** 0.36 *** -0.10 1.67 *** 0.27 ** -0.08 -0.06 0.20 0.48 *** -5.85 *** 0.02 *** Diabetes Model 1 Model 2 -0.12 0.44 ** 0.26 -7.37 *** -7.27 *** Hypertension Model 1 Model 2 -0.15 * 1.17 *** 0.14 * 0.14 *** 1.30 *** -0.02 -4.58 *** -0.12 1.22 *** 0.20 ** -0.29 *** -0.07 -0.02 1.11 *** 0.04 *** -3.81 *** 0.09 1.29 *** 0.10 * -0.22 *** -0.16 -0.15 0.58 0.14 ** * *** *** Lung disease Model 1 Model 2 0.53 *** 1.35 *** 0.05 0.39 *** 1.51 *** -0.04 -0.39 *** 0.34 1.09 0.84 -6.61 ** *** *** *** -5.94 *** Cancer Model 1 Model 2 -0.51 *** 1.49 *** 0.38 *** -6.16 *** -0.41 *** 1.58 *** 0.20 * 0.15 0.22 0.44 ** 0.30 * -6.67 *** Source: Weibull model estimates obtained by maximum likelihood. *** p<0.01, ** p<0.05, * p<0.1. Model 1: Includes controls for age, and gender. Model 2: adds controls for college education and health behaviors. Europe includes: Netherlands, Italy, France, Denmark and Spain. Spain is the reference country in Europe. Sample age 50-79. Sample weights used. 26 Table 4: Proportion dying in 2 years among those with a disease Heart disease 50-59 60-69 70-79 Total Stroke 50-59 60-69 70-79 Total Lung disease 50-59 60-69 70-79 Total Diabetes 50-59 60-69 70-79 Total Hypertension 50-59 60-69 70-79 Total Cancer 50-59 60-69 70-79 Total U.S. Europe (N= 3,273) (N= 1,128) 0.036 0.054** 0.102*** 0.067*** U.S. (N= 1,026) 0.047 0.087** 0.122 0.092** U.S. (N= 1,405) 0.046 0.079** 0.146* 0.090*** U.S. (N= 2,852) 0.038* 0.061** 0.100 0.064*** U.S. (N= 8,158) 0.020 0.033*** 0.073*** 0.039*** U.S. (N= 1,905) 0.031 0.079* 0.110 0.078 0.025 0.037 0.054 0.041 Europe (N= 353) 0.012 0.053 0.121 0.073 Europe (N= 668) 0.018 0.048 0.079 0.052 Europe (N= 1,124) 0.008 0.042 0.079 0.047 Europe (N=3,334) 0.005 0.027 0.045 0.027 Europe (N= 588) 0.047 0.033 0.104 0.018 Ratio 1.44 1.46 1.89 1.63 Ratio 3.92 1.64 1.01 1.26 Ratio 2.56 1.65 1.85 1.73 Ratio 4.75 1.45 1.27 1.36 Ratio 4.00 1.22 1.62 1.44 Ratio 0.66 2.39 1.06 4.33 Source: HRS and SHARE, age 50-79, sample weights used. Test of significance with condition (U.S. over Europe): * p<0.01, ** p<0.05, * p<0.1. The first two columns for both regions report the 2-year mortality rate for those diagnosed with a condition. The ratio of the two (U.S. over Europe) gives the relative mortality risk of those with a condition. 27 Table 5: Coefficients showing the effect on mortality of living in Europe relative to the U.S. for those with specified diseases (N in parentheses) Heart disease (4,497) Stroke (1,449) Lung disease (2,107) Diabetes (4,064) Hypertension (11,676) Cancer (2,535) Model 1 -0.51 *** -0.29 -0.44 ** -0.35 ** -0.44 *** 0.03 Model 2 -0.56 *** -0.33 -0.42 ** -0.36 ** -0.23 *** 0.02 Model 3 -0.65 *** -0.47 ** -0.55 *** -0.54 *** -0.65 *** -0.19 Model 4 -0.32 * -0.08 -0.30 -0.13 -0.28 ** -0.06 Source: HRS and SHARE, age 50-79, sample weights used. Gompertz models fitted by maximum likelihood. * p<0.01, ** p<0.05, * p<0.1. Each model is run for those with one disease at a time. Model 1: Includes controls for age, and gender. Model 2: adds controls for college education. Model 3: adds controls for health behaviors. Model 4: adds controls for comorbidities. 28 Table 6: Comparison of disease prevalence and incidence Heart disease Stroke U.S. Europe 9.0 4.3 2.2 1.2 U.S. Europe 3.9 4.5 1.3 1.7 U.S. Europe 6.7 4.1 9.2 7.3 U.S. Europe 18.3 10.1 5.5 2.8 Lung Disease Diabetes Prevalence 50-54 5.0 11.0 3.3 5.1 Incidence 50-79 1.7 3.6 3.6 4.2 Two-year mortality 50-79 9.0 6.4 5.2 4.7 Prevalence 50-79 8.2 15.7 6.0 10.8 Hypertension Cancer 32.7 18.0 4.9 3.3 10.2 15.5 2.5 1.6 3.9 2.7 7.8 1.8 46.8 31.4 10.7 4.9 Source: HRS and SHARE, age 50-79, sample weights used. 29 Figures Fig. 1 0 .02 .04 .06 2-year mortality rate .08 .1 Comparison of Survey Mortality rates and HMD life table mortality rates 2004 for U.S. and 5 European Countries 50 60 HRS age SHARE 70 US-HMD 80 EU-5-HMD Note: Curve of survey mortality rates smoothed using lowess filter and weighted using sampling weights SHARE includes: Denmark, France, Italy, the Netherlands, and Spain 30 Fig. 2 Prevalence of disease in Europe and the U.S. in 2004, Age 50-79 US Europe .5 .3 .2 .1 0 US Europe .5 Obese >35 0 .1 .2 .3 .4 .5 0 .1 .2 .3 .4 .5 .4 .3 .2 .1 0 US Europe Cancer Diabetes .4 .5 .4 .3 .2 .1 US Europe Hypertension US Europe Lung Disease 0 .1 .2 .3 .4 .5 Stroke 0 0 .1 .2 .3 .4 .5 Heart Disease US Europe US Europe Notes: Sample weights used. Europe includes: Denmark, France, Italy, the Netherlands, and Spain. Age 50-79. All significantly different. 31 Fig. 3 U.S. and European Incidence Rates by Age Heart disease Stroke 55-59 60-64 65-69 .01 .02 .03 .04 70-74 55-59 60-64 65-69 70-74 75-79 Diabetes * * * * * 0 0 .02 .02 .04 * * 50-54 .04 .06 Lung disease 75-79 .06 50-54 55-59 60-64 65-69 70-74 0 .05 .1 .15 .2 .25 Hypertension * * 60-64 65-69 50-54 55-59 60-64 65-69 70-74 75-79 Cancer * * * 65-69 70-74 0 * * 75-79 .01 .02 .03 .04 50-54 50-54 * 55-59 * 70-74 75-79 50-54 55-59 60-64 75-79 Class II Obesity * * 0 .01 .02 .03 * 0 0 .02 .04 .06 .08 .1 * 50-54 55-59 60-64 65-69 70-74 75-79 Notes: Dark bars refer to United States while grey bars to Europe. Europe includes: Denmark, Netherlands, France, Spain and Italy. Sample weights used to compute two-year incidence rates. 32 Appendix Evaluation of Mortality Reports and Effect of Differential Response Rates In Appendix Figure A.1 we show age-specific mortality estimated from surveys and from the Human Mortality Data Base (HMD) for 9 European countries in SHARE and the U.S. Mortality for the 5 countries we use in our analysis is quite close to those from HMD, with the exception of some ages for the Netherlands and Italy where survey-based estimates are slightly below the life table estimates. Average mortality rates (mx) at age 50 in 2004 in the HMD for the set of 9 European countries is 0.0035; while the average mortality rates for our subset 5 European countries is 0.0029. The mortality rate for the U.S. is 0.0044. In 2004, average life expectancy at age 50 in the HMD for the set of 9 European countries is 31.7 years; while life expectancy in our 5-country subsample is 31.8. At the same date, life expectancy in the U.S. is a year lower or 30.8 years. Because of high levels of non-reponse in SHARE, we analyzed the determinants of nonresponse for each country using multinomial logit models for responded, died and status unknown, with baseline demographic and health covariates (Table A.1 in the appendix). Overall, we found no consistent pattern across countries in the association of the observed characteristics with being in the unknown status, although some health conditions are negatively associated with non-response which would suggest that sicker individuals are more likely to have responded rather than be lost from SHARE. To measure how much these associations matter for our calculations, we constructed inverse probability weights to correct for selection on those observables following the strategy outlined by Michaud et al. (2011). We multiplied the SHARE baseline weight, which corrects for differential baseline non-response based age and socio33 demographics based using census information, by this inverse probability weight, which now corrects for differential non-response in the follow-up, to obtain a new weight. When we compared the distribution of this new weight to the weight provided by SHARE, we concluded that the distributions were similar and that our approach was similar to the SHARE approach in developing the weights. We also compared the incidence rates reported in our analysis based on SHARE weights with incidence rates based on our version of the weights and found them to be very similar. Therefore, we conclude that differential non-response is accounted for in the SHARE weights and unlikely to bias the inferences we make on the two populations. 34 Figure A.1 – Mortality from Surveys and the Human Mortality Database by countries 35 Table A.1 – Multinomial Logit Results: Charactertics associated with Death and Unknown Status Relative to Alive Status Variables Socio-demographic Age Male Foreign Marriage College Health behaviors Smoking Obese Health Conditions Cancer Hypertension Heart disease Stroke Diabetes Lung disease Any missing Constant Austria 0.08 0.50 -0.50 0.61 -0.11 *** * 0.31 0.29 1.72 -0.29 -0.55 0.60 -0.11 -0.56 0.81 -8.85 Belgium 0.11 0.75 -0.88 0.87 -0.04 1.08 -0.05 *** Austria Socio-demographic Age 0.01 * Male 6.99 Foreign 0.54 ** Marriage -0.09 College 0.00 Health behaviors Smoking 0.17 Obese -0.60 *** Health Conditions Cancer 0.21 Hypertension -0.44 *** Heart disease -0.34 Stroke -0.04 Diabetes 0.06 Lung disease -0.53 Any missing 13.96 Constant -8.39 Source: SHARE (2004) and HRS (2006) 0.67 -0.13 0.12 0.45 -0.84 0.57 1.45 -12.32 Denmark *** * * *** * 0.58 -0.85 *** Belgium 0.01 0.29 0.34 0.08 -0.01 0.08 -6.71 -0.68 -0.89 0.02 France 1.56 -0.36 -0.72 0.98 0.64 0.48 -14.01 -2.09 *** * 0.94 0.03 0.45 0.56 -0.32 0.85 -9.96 -4.08 0.00 0.41 0.35 0.03 -0.02 0.00 -0.10 0.03 -0.12 -0.03 -0.39 -0.14 -0.01 0.03 -0.37 0.00 0.33 0.57 -1.86 -0.26 -0.45 -0.07 0.16 0.40 -0.03 1.23 -1.97 * * *** *** ** *** 0.11 -0.00 -0.52 -0.36 -0.06 Greece *** 0.38 -0.15 -0.13 -0.16 -0.17 -0.08 -0.03 -0.03 0.75 -0.99 * ** 0.01 0.34 0.27 -0.33 0.00 *** 0.18 -0.18 ** -0.11 -0.03 0.02 0.18 0.05 -0.04 0.70 -0.87 * *** 0.09 -5.05 1.17 -0.78 0.00 Italy *** * * -0.53 0.29 1.77 *** 0.24 0.86 * 0.12 0.21 * -0.14 0.00 92.05 Panel B: Status Unknown France Germany 0.01 0.58 -0.08 0.02 -0.01 * *** 0.24 -0.15 Denmark * 0.08 -4.60 0.03 0.09 -0.13 Germany Panel A: Died ** *** * 1.83 0.88 0.45 0.28 -0.43 -0.41 -11.28 -4.53 0.11 0.81 -4.70 -0.84 0.01 Netherlands *** ** * 0.65 -0.33 ** ** Greece 1.31 0.25 0.24 0.91 0.96 0.35 3.44 -12.94 0.01 -5.58 -2.40 -0.48 -0.03 -0.12 0.33 ** * ** ** *** Italy 1.26 -0.54 0.91 1.19 0.12 0.24 0.20 -14.55 0.01 0.11 0.44 -0.33 0.02 ** * 0.01 0.86 0.27 0.26 0.00 0.17 -0.08 -0.21 -0.36 * ** -0.27 -0.04 -0.34 0.03 -0.28 -0.61 0.38 -2.43 -0.14 0.07 -0.03 -0.17 -0.19 -0.47 0.01 -1.18 *** * * 0.01 0.31 -0.10 -0.74 0.01 0.17 -0.51 ** * ** *** Netherlands 0.01 0.21 0.26 0.11 0.01 * *** Spain *** -0.03 0.18 0.09 0.67 0.67 0.15 -0.16 -9.98 Sweden *** ** * * ** Spain 0.13 0.47 -0.14 0.22 0.01 *** 0.76 -1.31 * * 0.70 0.23 0.05 0.39 0.50 1.41 0.20 -14.55 *** Sweden 0.00 -0.01 -0.08 -0.38 0.01 *** * 0.01 0.17 0.04 0.14 0.00 0.01 0.00 -0.10 -0.24 -0.17 -0.14 * ** 0.02 -0.11 0.00 -0.10 0.12 -0.19 1.71 -2.48 0.09 -0.28 0.11 -0.27 0.32 -0.33 0.00 -0.25 0.32 -0.08 0.06 0.01 -0.05 -0.15 0.41 -1.29 * ** * *** ** ** 36 ** **
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