Dietary intake and the insulin-like growth factor system: effects of migration in two related populations in India and Britain with markedly different dietary intake
Heald, A.H.; Sharma, R.; Anderson, S.G.; Vyas, A.; Siddals, K.; Patel, J.; Bhatnagar, D.; Prabharkaran, D.; Rudenski, A.; Hughes, E.; Durrington, P.; Gibson, J.M.; Cruickshank, J.K.
Public Health Nutrition 8(6): 620-627
2005
ISSN/ISBN: 1368-9800 PMID: 16236191 DOI: 10.1079/phn2005729Document Number: 256665
Background: The insulin-like growth factor (IGF) system is implicated in the pathogenesis of diabetes and cardiovascular disease. Objective: We report the effects of total energy intake on the IGF system in two populations with markedly different dietary macronutrient intake and cardiovascular event rate. Design, subjects and setting: 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, IGF-binding protein (IGFBP)-1 and IGFBP-3, insulin and glucose (0 and 2-hour) were measured. Results: Total energy and total fat intake were higher in UK migrants, as were IGFBP-3 and IGF-I (mean (95% confidence interval): 145.9 (138.1-153.6) vs. 100.9 (94.6-107.3) ng ml-1; F=76.6, P<0.001). IGFBP-1 was lower in UK migrants (29.5 (25.9-33.0) vs. 56.5 (50.6-62.5) micro g l-1; F=48.4, P<0.001). At both sites, IGF-I correlated positively with total energy (Spearman's 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, in Indian Gujaratis, IGFBP-1 fell with increasing total energy ( rho =-0.27, P<0.001) and fat intake ( rho =-0.26, P<0.01) but not in UK Gujaratis. Multiple linear regression modelling showed that increasing quartiles of fat intake were associated with higher IGF-I ( beta =0.42, P=0.007) independent of age, body mass index, plasma insulin, fatty acids and 2-hour glucose. Conclusion: In these genetically similar groups, migration to the UK and adoption of a different diet is associated with marked changes in the IGF system, suggesting that environmental factors profoundly modulate serum concentrations and actions of IGFs.