MORTALITY IN MICRONESIAN NAURUANS AND MELANESIAN AND INDIAN FIJIANS IS NOT ASSOCIATED WITH OBESITY

The association of obesity with mortality was investigated in populati on-based samples of Micronesian Nauruans (n = 1,400), Melanesian Fijia ns (n = 1,279), and Indian Fijians (n = 1,182), over 10 years from 198 2 in Nauru, and 11 years from 1980 in Fiji, At the end of follow-up, v ital status was known for all Nauruans and all but 3.5% of Fijians. Mo rtality rates were higher in Nauru than Fiji, and in Melanesians than Indians. The mean body mass index of decedents was similar to or less than (Nauruan men, p < 0.001) that of survivors in each sex-ethnic gro up, Crude mortality rates showed an inverse relation with body mass in dex in Nauruan men, with inconsistent relations in other sex-ethnic gr oups, After stratification by diabetes status, there was no relation b etween mortality and obesity in nondiabetic subjects, but an inverse r elation was observed among diabetic subjects in each population. These findings persisted even after the exclusion of subjects who died with in the first 2 years of follow-up. After controlling for age, smoking, and diabetes status in Cox proportional hazard models, body mass inde x (as a continuous variable) was not related to mortality in any sex/e thnic group and tended to be negatively associated with mortality risk . Interactions of body mass index with age, smoking, and diabetes stat us were not significant, Mortality risk was significantly increased in older subjects and in diabetic subjects, and cigarette smoking also i ncreased risk in some groups, Stratification of analyses according to cigarette smoking did not alter the nature of the results. The associa tion of mortality and body mass index categorized by quartiles was als o investigated. After adjusting for age alone, or age, smoking, and di abetes status, the lower quartiles of body mass index were consistentl y associated with the highest relative risk for mortality. Quadratic t erms for body mass index did not improve Cox models in subjects with n ormal glucose tolerance, Relations with cardiovascular disease mortali ty were also assessed and results were inconsistent, although positive trends were observed in Nauruan women (p = 0.02) and Melanesian men ( p = 0.06), Overall, there was little evidence to suggest that obesity was a risk factor for total or cardiovascular mortality in these popul ations. However, obesity is clearly associated with a high risk of dia betes and other morbid conditions and at least on this basis it would seem desirable to prevent obesity in these and other Pacific populatio ns.