Anthropometric and Behavioral Correlates of Insulin-like Growth Factor I and Insulin-like Growth Factor Binding Protein 3 in Middle-aged Japanese Men

High levels of plasma insulin-like growth factor I (IGF-I) and low levels of insulin-like growth factor binding protein 3 (IGFBP-3) have been related to increased risk of several cancers. Little is known about the behavioral determinants of these biologic markers. The authors examined the relation of anthropometric and behavioral factors to plasma concentrations of IGF-I and IGFBP-3 in a cross-sectional study of 616 Japanese men aged 45–55 years in 1995–1996. In univariate analyses, body mass index was strongly, positively associated with both IGF-I and IGFBP-3. The waist/hip ratio was also linearly related to IGF-I and IGFBP-3 up to the third quartile level. Height was weakly, positively associated with IGF-I and IGFBP3. Smoking was inversely associated with IGF-I and IGFBP-3. Alcohol use was associated inversely with IGF-I and positively with IGFBP-3. Neither IGF-I nor IGFBP-3 was related to physical activity. Results of the multivariate analysis were essentially the same as those of the univariate analyses. The findings regarding body mass index are in contrast to those of previous studies showing null or inverse associations, and they suggest that the relation of body mass index to IGF-I or IGFBP-3 may vary among populations. The study also indicates that smoking and alcohol use might affect plasma IGF-I and IGFBP-3.