The IGF-system has also been implicated in the pathogenesis of diabetes and cardiovascular disease. We report the effects of total energy intake on the IGF-system in two populations with a markedly different dietary macronutrient intake and cardiovascular event rate.
Dietary macronutrient intake was measured in a specific Gujarati migrant community in Sandwell UK (n=205) compared with people still resident in the same villages of origin in India (n=246). Fasting IGF-I, IGFBP-1 and IGFBP-3 were measured.
IGFBP-1 was lower in UK migrants (29.5 (25.9-33.0) mcg/l) vs (56.5 (50.6-62.5) mcg/l); F=48.4, p<0.001. IGFBP-3 was markedly higher in both UK migrant Gujarati men (3.9 (3.7-4.1)mg/l) and women (3.9 (3.7-4.1)mg/l) than Indian Gujarati men (3.5 (3.3-3.7)mg/l) and women (3.5 (3.3-3.7)mg/l; F=6.4, p<0.001) as was IGF-I (145.9 (138.1-153.6 ng/ml vs 100.9 (94.6-107.3 ng/ml); F = 76.6, p < 0.001). Total energy intake was higher in UK migrants (men 2221 (2054-2386 mean, 95% CI), women 1720 (1595-1847)) kcal/day than in the Indian Gujaratis (men 1478 (1347-1610), women 1260 (1174-1348)) kcal/day. Similar differences were seen for total fat intake. IGF-I correlated positively with total energy (rho=0.45, p<0.001) and total fat (rho=0.44, p<0.001) as did IGFBP-3 with total energy (rho=0.21, p<0.05) and fat (rho=0.26, p<0.001). Conversely IGFBP-1 fell with increasing total energy (rho=-0.27, p<0.001) and fat intake (rho=-0.26, p<0.01). Multiple linear regression modelling showed that increasing quartiles of total energy intake were associated with higher IGF-I (beta = 0.12, p=0.02) independent of age, gender, BMI, insulin and 2hour glucose.
Migration to the UK and the adoption of a different diet results in changes in IGF system consistent with those known to predispose to increased cardiovascular risk. These data provide important evidence for the effect of environmental factors in modulating genetic influences on the concentration and biological effects of IGFs in a genetically similar population.
22 - 24 Mar 2004
British Endocrine Societies