Age- and Sex-Related Interactions between Insulin-Like Growth Factor-I Promoter Polymorphisms and IGF-I Levels

The present study explored sex-and age-related interactions of IGF-I polymorphisms with IGF-I serum levels. In 2000 data on IGF-I promoter polymorphism and IGF-I level were available of 344 (mean age 36; 162 men) and 6 years later in 287 subjects (133 men). As the sample sizes of groups of subjects with IGF-I genotypes 192/192, 190/192, 192/194 and 192/196 were large enough to be analyzed, the relationship between these specific genotypes and IGF-I-level was determined. The results indicated that in women aged 36 IGF-I levels for genotype 190/192 (mean 29.24 nmol/l) were higher than those for genotypes 192/192 (mean 24.29), 192/194 (mean 24.61) and 192/196 (mean 23.93). Male IGFI levels were decreased in 2006 compared to 2000 for genotypes 192/192 (mean decline - 3.67), 192/194 (mean decline - 1.61), 192/196 (mean decline - 4.18), but not for 190/192. Female IGF-I levels were decreased for genotypes 192/192 (mean decline - 1.85) and 190/192 (mean decline - 4.64), but not for 192/194 and 192/196. Thus females with genotype 190/192 have higher IGF-I levels, while females with genotypes 192/194 or 192/196 and males with genotype 190/192 do not show a decline of IGF-I level. © van Turenhout et al