Factors associated with the distribution of fasting plasma glucose in an adult community.

The fasting plasma glucose (FPG) was measured in 4170 nondiabetic adult residents of a suburban California community. At all ages the median FPG in men was higher (103-107 mg/dl) than the median FPG in women (96-104 mg/dl). FPG levels correlated weakly with obesity, and male-female differences persisted after adjustment for body mass index. In women, FPG levels rose at the age of menopause and tended to be lower in sex hormone-using women, suggesting that the male-female differences were related to estrogen. The FPG rose little with age (0.7 mg/dl/decade in men; 2.0 mg/dl/decade in women) in contrast to the 6-15 mg/dl/decade increment reported for glucose tolerance tests. These data suggest that the normal range of FPG is relatively independent of age and body mass, and that the male-female differences are not sufficiently great to necessitate sex-specific standards.