Exercise protects against glucose intolerance in individuals with a small body size at birth.

Abstract

Small body size at birth is a risk factor for Type 2 diabetes. We investigated whether regular exercise is related to lower rates of glucose intolerance in individuals with a small body size at birth and whether birth size affects exercise habits in adulthood. Five hundred subjects aged 65-75 years with data on birth measurements underwent an oral glucose tolerance test. They reported their weekly exercise frequency and intensity and yearly physical leisure time activity. Frequent (> or = 3/week) or moderate weekly exercise and yearly physical activity were all related to lower rates of glucose intolerance. This effect was, however, dependent on birth size, being strongest among subjects with a small body size at birth (birth weight < or = 3000 g and/or ponderal index < or = 26 kg/m3). Among men, frequency (P = 0.033) and intensity (P = 0.030) of exercise as well as yearly physical activity (P = 0.005) correlated inversely with birth size. Subjects predisposed to Type 2 diabetes due to a small birth size are strongly protected from glucose intolerance by regular exercise. Although a small body size at birth is related to a smaller muscle mass in adulthood, men born thin exercised more in adulthood than those not born thin. In these elderly subjects this might indicate the survival of the fittest.