Social Differences in Insulin-like Growth Factor-1: Findings from a British Birth Cohort

Purpose Insulin-like growth factor-1 (IGF-1) is related to factors that are socially patterned and may play a role in social differences in the development of morbidities including disability. Our aim is to examine whether there are social differences in IGF-1 in a cohort of participants between 44 and 45 years of age. Methods We examine the association of IGF-1 with social position measured by fatherʹs or own occupational class at three time points in childhood and adulthood, in a cohort of individuals born in one month in 1958 (N = 3,374 men and 3,302 women). Results Lower IGF-1 levels were associated with lower social position measured with fatherʹs occupational class at birth (p < 0.0001) and own occupational class aged 42 years (p < 0.001). Adult social position was associated with IGF-1 independently of social position at birth (p < 0.001) or any covariates examined. Conclusions IGF-1 secretion is associated with social position such that low social position is associated with lower levels of IGF-1. This biomarker may play a role in the development of social differences in morbidities associated with aging, such as the development of disability.