Age and sex variations in glucose tolerance and insulin responses: parallels with cardiovascular risk.

The venous plasma glucose and insulin concentrations recorded during oral glucose tolerance testing of over 300 1st degree relatives (parents and siblings) of insulin dependent diabetics are presented. Men had higher glucose concentrations than women, the difference increasing with age, while insulin responses appeared greater in adolescent girls and young women than their male counterparts. The possible relationship between the different insulin responses in the two sexes and the sex difference in cardiovascular risk factors is discussed. It is suggested that the absence of a marked sex differential in heart disease mortality amongst diabetics may partly result from the loss by diabetic women of their greater insulin production relative to men in young adult life.