WEIGHT FLUCTUATION, MORTALITY AND VASCULAR-DISEASE IN PIMA-INDIANS

OBJECTIVE: To examine the relationship of weight fluctuation to mortal ity rates and incidence of vascular disease. SUBJECTS: A cohort of Pim a Indians, 572 of whom had non-insulin-dependent diabetes mellitus and 766 without diabetes. DESIGN: Individuals were invited biennially to research examinations, The root mean square error (RMSE) of the linear trend of weight with time for the first four examinations after age 2 0 years was used as an index of weight fluctuation. Subjects were foll owed from the fourth examination until death or until 31 December 1991 . The mortality rate ratio (MRR) and its 95% confidence interval (CI) for those with a high weight fluctuation index relative to those with a lower value were determined. The median duration of follow up was 9. 3 (range 0.1-22.6) years. MEASUREMENTS: All cause mortality (n = 356); incidence of diabetic retinopathy (n = 145), diabetic nephropathy (n = 132) and electrocardiographic abnormalities (n = 82). RESULTS: There was no significant relationship between weight fluctuation and mortal ity for diabetic subjects (MRR = 1.0, 95% CI 0.8-1.3, p = 0.91). Nondi abetic subjects with a high weight fluctuation index had a higher mort ality rate than those with a lower index (MRR = 1.5, 95% CI 1.0-2.1. p = 0.03); the association was stronger among men than among women, The excess mortality in the high weight fluctuation group was not due to cardiovascular diseases, but to noncardiovascular causes and the risk for alcohol-related death was particularly increased, Weight fluctuati on was not associated with the incidence of diabetic retinopathy, neph ropathy or electrocardiographic abnormalities. CONCLUSIONS: A high wei ght fluctuation index was associated with higher mortality rates in no ndiabetic, but not in diabetic, Pima Indians. The excess mortality is largely due to noncardiovascular causes of death and may reflect lifes tyle factors associated with weight fluctuation, rather than its metab olic effects.