Long term fish intake seems to confer to preserved renal function in elderly individuals: the IKARIA study
Christina Chrysohoou, Theodora Psaltopoulou, Costandina Masoura, Georgia Triantafyllou, Gerassinos Siasos, John Andreou, Nikos Galiatsatos,
Dimitris Tousoulis, Christos Pitsavos Christodoulos Stefanadis
1st Cardop;pgy Clinic University of Athens. Greece
Renal insufficiency has been recognized as an independent risk factor for cardiovascular and
all-cause mortality, especially in elderly individuals. Among other lifestyle factors, the
omega-3 polyunsaturated fatty acids in fish oil have been shown to produce beneficial
effects, such as a reduction in blood pressure, proteinuria, lipid levels and inflammation
However, data regarding the effect of long term fish consumption on renal function among
elderly are limited. The aim of this study was the evaluation of the impact of fish
consumption in respect of the overall dietary habits, on renal function in elderly inhabitants
of Ikaria Island; a place that has been related with increased rates of longevity. Methods.
From June to October of 2009, we studied 343 men and 330 women, aged 65 to 100 years,
permanent inhabitants of Ikaria Island. Among several socio-demographic, bioclinical,
lifestyle and dietary characteristics, cardiovascular disease (CVD) factors like hypertension,
diabetes, hypercholesterolemia, obesity and anthropometric indices, nutritional habits,
including weekly fish intake, were evaluated using a semi-frequent food questionnaire and a
diet score that assesses the inherent characteristics of the Mediterranean diet (MD) was
developed for each individual (range 0-55).Urea and creatinine were measured, and
creatinine-clearence (CCr) rate was estimated by the Cockcroft-Gault formula. Results. 637
(49% males, mean age 75±6 years old) individuals were emroled. From them 84% reported
regular fish consumption.;84% were defined as physical active, 17% reported current
smoking, 21% having CVD, 29.5% obesity, 28.5% diabetes, 66% hypercholesterolemia,
72% hypertension and 65% showed CCr>60ml. CCr rate was positively associated with fish
intake in gr/day (b±SE: 0.24±0.09, p=0.007). ANOVA revealed that those participants
having normal CCr (>90 ml) were younger, had lower prevalence of CVD, hypertension,
higher hemoglobin levels, lower CCr, urea, creatinine, and reported higher quanitities of
weekly fish intake and physical activity levels (all p<0.05), compared to those with CCr<90
ml and <60 ml. Linear Regression analysis after adjustment for physical activity status,
MedDietScore, CVD, hypertension, current smoking and diabetes, revealed that fish
consumption (g/day) was related with CCr (B=0.109±0.027, p=0.001). Furthermore, logistic
regression analysis showed that fish consumption of 100g/day increases the likelihood by
150% of having CCr>60ml. (95%CI 1.007-1.022), after the same adjustments were made.
Conclusion. Long term fish consumption seems independently of the adherence to the
Mediterranean diet, to be associated with reduced urea, creatinine and increased CCr rates
among elderly individuals. This finding, adds to the current knowledge regarding the
benefits of fish and omega-3acids on human health.
Table 1. Lifestyle, clinical and biochemical characteristics of the participants (n=667), according to creatinine clearance levels.
Men (n=328)
Women (n=339)
Creatinine Clearance (ml)
Subjects (%)
Age (yrs)
Current smoke
MedDietScore
Fish intake
Physical active (%)
UA (mg/dl)
<60
60-90
>90
28
31
41
81±6
75±5*
71±5*
22
25
37±3
P
<60
60-90
>90
39
36
26
<0.001
80±6
74±5*
72±5*
<0.001
26
0.78
13
11
10
0.77
38±2
38±2.5
0.58
39±3
38±4
37±3
0.79
45.3±29.8
56.3±48.9
67.7±53.2
0.003
33.8±28.8
38.6±28*
49.0±39.0*
0.003
86
88
89
0.78
77
84
78
0.34
7.04±1.49
6.28±1.42*
6.03±1.54*
5.72±1.63
5.10±1.29*
5.11±1.24*
0.001
<0.001
15
24*
60*
<0.001
<0.001
P
Obesity (%)
16
20
44*
diabetes mellitus (%)
41
29
29
0.12
24
22
30
0.44
Hypertension (%)
76
62
66
0.14
77
73
72
0.66
Hypercholesterolemia
58
66
67
0.38
69
71
65
0.70
CVD
34
17*
21*
0.02
23
20
13
0.19
Table 32 Results from multiple linear regression analysis that evaluated the association between fish consumption and creatinine
clearance levels.
Women
It was observed that regular fish consumption, irrespectively of overall dietary habits,
seems to be a non-pharmacological mean in the maintenance of preserved kidney
function among elders. Therefore, public health strategies could give further attention on
the role of fish, and omega-3 fatty acids consumption on fight against kidney failure
among the elders.
Men
b±SE
p
b±SE
p
Fish consumption (per 1 g /day)
0.21±0.05
<0.001
0.07±0.03
0.03
MedDietScore (per 1/55 unit)
-1.00±0.48
0.04
0.18±0.55
0.74
Physical activity (yes vs. no)
-5.00±4.48
0.26
3.32±4.58
0.46
Diabetes (yes vs. no)
1.87±4.08
0.65
-5.72±3.20
0.08
Hypertension (yes vs. no)
-2.85±3.68
0.44
-0.63±3.12
0.83