ORIGINAL ARTICLE
The Trends of CRP Levels at Different Waist-to-Hip Ratios Among
Normotensive Overweight and Obese Patients: A Pilot Study
ABSTRACT
Samar Firdous1, M. Omar Khan Lodhi2 and Kashif Siddique3
Objective: To determine the correlation between CRP (C-reactive protein) and Waist to Hip Ratio (WHR) among over
weight and obese patients with normal blood pressure.
Study Design: An analytical study.
Place and Duration of Study: Medical indoor and outpatient clinics of Mayo Hospital, Lahore, from March to August
2013.
Methodology: Willing patients with Body Mass Index (BMI) of > 23 kg/m2, normal blood pressures, and age between
18 - 65 years were inducted in the study. Patients with signs of fluid retention, collagen vascular disease, CAD, on
corticosteroids, immunomodulators or lipid lowering medications, hypertensives and febrile patients were excluded.
Patients were considered to be at low risk for cardiovascular events if WHR among males and females was < 0.95 and
< 0.80, respectively. Similarly, males and females with WHR > 1 and > 0.85, respectively were taken as high risk. Levels
in-between these ranges were taken as moderate risk. Data was analyzed on SPSS 15. Descriptive statistics were
determined. The p-value was calculated by ANOVA and independent sample t-test among males and females respectively,
to compare WHR in relation to different CRP levels and < 0.05 was taken as significant.
Results: There were 34 male and 74 female patients. The gender-wise mean WHR did not show statistically significant
difference categorized CRP levels (p=0.072 in male, and 0.052 in females). There was an increasing trend in CRP levels
as WHR increased among females, but this was statistically insignificant (p=0.05).
Conclusion: Although the impact of central obesity on cardiac health is well known, however, WHR alone is an unreliable
indicator of systemic inflammation and raised CRP level.
Key Words: CRP (C-reactive protein). Waist-to-Hip Ratio (WHR). Normal blood pressure. Cardiovascular risk.
INTRODUCTION
Obesity is a notorious risk factor for cardiovascular
events and a strong component of metabolic syndrome.
It is the distribution of fat in the body that leads to future
risk of cardiovascular disease, insulin resistance and
non-insulin dependent diabetes mellitus.1 Central
obesity due to presence of mesenteric and omental fat is
more dangerous than sub-cutaneous fat. People with
apple type of body habitus (android obesity) are more
prone to cardiovascular disease than people with pear
type of body shape (gynoid obesity).2 There are different
ways to detect and categorize obesity like waist
circumference, waist to hip ratio, body mass index and
skin fold thickness.3 People with similar Body Mass
Index (BMI) may not have the same Waist-to-Hip ratio
(WHR) due to different distribution of fat. WHR can pick
central distribution of fat. A WHR of 0.85 or more is
significant in females and a ratio of 0.95 or more for
1
2
Department of Medicine, King Edward Medical University,
Lahore.
Health Department Punjab / Statistician3, Mayo Hospital,
Lahore.
Correspondence: Dr. Samar Firdous, Assistant Professor of
Medicine, King Edward Medical University, Lahore.
E-mail: [email protected]
Received: August 05, 2014; Accepted: December 01, 2015.
males: and is more strongly associated with risk of
adverse cardiovascular outcome.4 The only limitation of
WHR is the chance of error because of thick muscle
mass and large hip bone in some people leading to
increased hip circumference. In such cases, WHR is not
an accurate marker of obesity.5
C-reactive Protein (CRP) is an inflammatory marker that
is not only associated with inflammatory conditions of
the body, but it is also raised in people with established
cardiovascular disease or those with one or more risk
factor for it.6 Researchers recommend routine testing for
CRP in high risk patients with one or more
cardiovascular risk factors. So, men over 50 years and
women over 60 years should be offered CRP testing to
determine their future cardiac risk and to offer
appropriate preventive therapy including statins.7
The rationale of this study was to determine the
relationship between CRP level and WHR among
patients who were either overweight or obese. Since
CRP is an inflammatory marker that is related to the
presence of other cardiovascular risk factors like
smoking, obesity, diabetes, hypertension etc.; so the aim
of this study was to evaluate subjects with normal blood
pressure and body mass index of > 23 kg/m2 to
determine association of CRP with WHR and excluding
hypertension as a possible confounder having
association with raised CRP level.
Journal of the College of Physicians and Surgeons Pakistan 2016, Vol. 26 (3): 191-194
191
Samar Firdous, M. Omar Khan Lodhi and Kashif Siddique
METHODOLOGY
After an overnight fast, blood samples were collected for
CRP levels. CRP was measured by Latex enhanced
nephelometry. CRP level of < 1 mg/L was considered
low, values between 1 - 3 mg/L were considered to be
average and those > 3 mg/L were taken as high.7
It was an analytical study. After approval from
Institutional Review Board of Mayo Hospital, Lahore, it
was conducted in medical wards on patients who
presented in emergency or OPD clinic from March till
August 2013. Willing patients having age between
18 - 65 years, blood pressure < 140/90 mm Hg, and BMI
> 23 kg/m2 were recruited. Detailed medical history was
taken and clinical examination was done to identify any
exclusion criteria. Patients with signs of fluid retention
(like cardiac, renal or hepatic failure), ascites due to any
cause, arthritis, acute febrile illness, hypertension and
patients on drugs like corticosteroids, immunomodulators, statins or antihypertensive medications
were excluded from the study.
Data entry and analysis was done by using SPSS 15.
Quantitative variables were presented by using mean
and standard deviations. Qualitative variables were
presented by using frequency table and percentages.
Analysis of variance was used to compare the waist-tohip ratio in relation to different CRP level. The p-value
was calculated by ANOVA and independent sample
t-test among males and females, respectively. A p-value
of < 0.05 was taken as significant.
RESULTS
After assessing the recruitment criteria, 108 patients
were selected. Informed consent was taken from
patients and BMI was calculated using formula; BMI =
weight (kg)/height (m)2.
This study was conducted on 108 subjects. There were
34 male and 74 female patients in the study. Mean CRP
level among male and female patients was 4.85 ±2.32
and 4.45 ±2.60, respectively. Similarly, WHR among
male and female patients was 0.924 ±0.080 and 0.865
±0.083, respectively. Male patients with average CRP
level (1 - 3 mg/L) showed normal WHR (0.88 ±0.05),
whereas males with high CRP level (> 3 mg/L), exhibited
average WHR (0.94 ±0.08).
Instead of WHO criteria, BMI criteria for Asians by
Regional Office for Western Pacific Region of WHO
(WPRO criteria) for obesity were applied as WPRO
criteria have BMI cut-off point much lower than WHO
criteria.8 Patients of BMI ≥ 23 kg/m2 were recruited.
Waist circumference was noted at the point, midway
between costal margin and anterior superior iliac spine
(usually just above the umbilicus). Hip circumference
was measured at the widest part. Patients were
considered to be at low risk for cardiovascular events, if
WHR among males and females was < 0.95 and < 0.80,
respectively. Similarly, males and females with WHR > 1
and > 0.85, respectively were taken as high risk. Levels
in-between these ranges were taken as moderate risk.4
Females with normal CRP level (< 1 mg/L) showed
moderated risk with mean WHR of 0.84 ±0.07.
Moreover, mean WHR among females with average
(1 - 3 mg/L) and high CRP levels (> 3 mg/L) was 0.89
±0.10 & 0.87 ±0.08, respectively. In both genders, the
mean WHR was statistically insignificant in correlation to
categorized CRP levels (p-value for WHR in males was
0.054 and 0.202 for females) . However, it was observed
that high risk male patients with CRP level > 3 mg/L had
higher values of WHR than the males with average CRP
level of 1 - 3 mg/L.
Table I: CRP and waist-to-hip ratio (WHR) in male and female patients.
CRP
Waist-to-hip ratio
WHR and CRP correlation
< 1 mg/L
1 - 3 mg/L
> 3 mg/L
p-value (ANOVA)
Male (n = 34)
Female (n = 74)
0.924 ±0.080
0.865 ±0.083
4.852 ±2.324
-
0.88 ±0.05
0.94 ±0.08
0.054
4.450 ±2.60
CRP levels were not significantly associated with WHR
(p-values in males and females were 0.072 and 0.052
respectively). Although female patients showed an
increasing trend in CRP level rise as WHR increased,
however this was not statistically significant (p=0.05).
Similarly no significant linear correlation was observed
0.89 ±0.10
0.84 ±0.07
0.87 ±0.08
0.202
Table II: Categorized CRP and WHR for male and female patients.
Number
CRP
< 1 mg/L
1 - 3 mg/L
> 3 mg/L
Chi-square test
p-value
Correlation of CRP with waistto-hip ratio
CRP
192
<0.80
25
4
10
11
Risk criteria for WHR (females)
0.81-0.85
13
0
5
8
9.373
> 0.85
36
0
12
24
< 0.95
22
-
10
12
Risk criteria for WHR (males)
0.96 - 1
6
-
1
5
5.270
0.052 (insignificant)
0.072 (insignificant)
0.133 (p-value:0.257)
0.191 (p-value:0.278)
>1
6
-
0
6
Journal of the College of Physicians and Surgeons Pakistan 2016, Vol. 26 (3): 191-194
CRP and WHR among normotensive overweight and obese patients
with Pearson correlation for CRP level and WHR among
male and female patients (r=0.133 (p=0.257) and
(r=0.191, (p=0.278 respectively).
DISCUSSION
CRP is an important marker of inflammation that is
released from the liver in response to some infection,
inflammation or vascular endothelial injury. In healthy
subjects, it is found in traces in the blood. Many previous
studies have shown a significant association of raised
CRP with components of metabolic syndrome,
endothelial dysfunction and atherogenesis. It potentiates
the effect of traditional cardiovascular risk factors but it
is not well known whether lowering CRP decreases this
risk or not.7,9
The markers of obesity are body mass index, skin fold
thickness, waist circumference and WHR. Body mass
index is a measure of heaviness. It does not depict the
pattern of fat accumulation in the body. Skin fold
thickness indicates the presence of sub-cutaneous fat in
the body. On the other hand, waist circumference is
related to the presence of visceral fat that leads to
central obesity. Similarly, WHR is a reflection of fat
distribution in different parts of the body. It is a better
indicator of central obesity which carries significant
cardiovascular risk.4
In 1999, Visser et al. conducted a study in the USA on
3512 overweight children and their normal weight peers.
They concluded that markers of obesity like skin fold
thickness and BMI are associated with high CRP levels,
suggesting the presence of low grade inflammation
among overweight children.10 This is further supported
in 2006 by the research work of Thorand et al. in
Germany. They suggested that adiposity is strongly
associated with markers of low grade systemic
inflammation and this is especially true among females
for raised CRP levels.11
A Taiwanese study done by Cheng et al. in 2010 on 1669
individuals showed a strong association of all indicators
of obesity (% fat mass of body, BMI, WHR and waist
circumference) with high CRP levels among female
patients; whereas in males, WHR was not associated
with high CRP levels. However, the percentage fat mass
was the only indicator of adiposity that had a positive
association with raised CRP levels. They stressed the
importance of estimating percentage fat mass of body as
a better indicator of obesity for determination of
cardiovascular risk.12 Their results in the male
population are strongly consistent with our results. This
is primarily due to same demographics (i.e. South Asian
region) of the two study populations.
According to a Finnish study done by Gang et al., high
sensitivity CRP was associated with increased risk of
developing type 2 diabetes mellitus and this association
was much stronger in females as compared to males.13
In this study, the female patients had a trend of higher
CRP level as the waist-to-hip ratio increased, but this
was not statistically significant. This increasing trend
among female gender is consistent with this Finnish
study.
Craig et al. conducted a research in 2007 on 767
subjects from Tongan population to identify cut points in
anthropometric indexes to predict undiagnosed diabetes
and cardiovascular risk estimation.14 They used BMI,
waist circumference, weight-to-height ratio, percentage
fat mass estimation and WHR to determine undiagnosed
diabetes and cardiovascular risk. Their study showed
marked difference in cut points as compared to Asian
and Caucasian populations.
Thimpson et al. worked on British women in 2005, to
determine association between CRP and phenotypic
components of the metabolic syndrome. They concluded
that BMI, WHR, systolic blood pressure and insulin
resistance were associated with CRP levels. However,
the instrumental variable analysis showed no causal
association between CRP and phenotypes of metabolic
syndrome.15
There had been numerous studies to find association of
these anthropometric measurements with overall
cardiovascular risk. Many researchers prefer to consider
waist circumference and WHR as better indicators of
central obesity and hence future risk of morbidity and
mortality due to cardiac problems, whereas others
label BMI as a better parameter.16,17 The main aim of
these measurements is estimation of visceral fat
accumulation, which is an important component of
metabolic syndrome.18,19 Halting this process of fat
accumulation by early recognition of visceral obesity,
life-style modification or pharmacological treatment of
underlying conditions is important to achieve better
outcomes.20
To the best of author’s knowledge, this is the first attempt
to study the relationship of CRP with anthropometric
index, i.e. WHR, among subjects in Lahore. However, in
future, the authors plan to extend their research as a
longitudinal study of these parameters in detail with
large group of patients.
CONCLUSION
Although impact of central obesity on cardiac health is
well known; however, WHR alone is an unreliable
indicator of systemic inflammation. In fact, taking an
account of all determinants of central obesity (e.g.: BMI,
skin fold thickness, waist circumference and percentage
fat mass of the body) is a better method to judge the
presence of raised CRP, leading to endothelial injury,
vascular inflammation, atherogenesis; and hence, future
risk of developing complications due to cardiovascular
disease.
Journal of the College of Physicians and Surgeons Pakistan 2016, Vol. 26 (3): 191-194
193
Samar Firdous, M. Omar Khan Lodhi and Kashif Siddique
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