The association of physical activity with obesity, fat distribution and glucose intolerance in Pima Indians

The relationships between physical activity, obesity, fat distribution and glucose tolerance were examined in the Pima Indians who have the highest documented incidence of non-insulin-dependent diabetes. Fasting and 2-h post-load plasma glucose concentrations, body mass index, and waist-to-thigh circumference ratios were determined in 1054 subjects aged 15-59 years. Current (during the most recent calendar year) and historical (over a lifetime) leisure and occupational physical activity were determined by questionnaire. Current physical activity was inversely correlated with fasting and 2-h plasma glucose concentrations, body mass index and waist-to-thigh ratios for most sex-age groups even when diabetic subjects were excluded. Controlled for age, obesity and fat distribution, activity remained significantly associated with 2-h plasma glucose concentrations in males. In subjects aged 37-59 years, individuals with diabetes compared to those without reported significantly less leisure physical activity during the teenage years (median hours per week of activity, 9.1 vs 13.2 for men; 1.0 vs 2.2 for women). Controlled for body mass index, sex, age and waist-to-thigh ratio, subjects who reported low levels of historical leisure physical activity had a higher rate of diabetes than those who were more active. In conclusion, current physical activity was inversely related to glucose intolerance, obesity and central distribution of fat, particularly in males. Subjects with diabetes were currently less active and reported less historical physical activity than non-diabetic subjects. These findings suggest that activity may protect against the development of non-insulin-dependent diabetes both directly and through an influence on obesity and fat distribution.