Dramatic increase in the prevalence of obesity in western Samoa over the 13 year period 1978-1991.

Obesity and an increasing prevalence of associated conditions such as diabetes and cardiovascular disease are frequently observed in Pacific populations as lifestyles become more modernized. In 1978, a survey conducted in three geographically defined populations in Western Samoa showed large differences in the prevalence of obesity (body mass index (BMI) > or = 30 kg/m2) between rural and urban populations. A follow-up survey using similar methods was performed in 1991 to examine the current level of obesity in these three locations and to assess changes over time. Cross-sectional differences in the prevalence of obesity, mean BMI and waist-hip circumference ratio (WHR) between urban Apia and rural Poutasi and Tuasivi were examined after adjusting for age. There were higher levels of obesity in urban vs rural areas: 74% of women in Apia were obese compared with 62% in Poutasi and 56% in Tuasivi. In men, comparable figures were 57%, 44% and 36% for Apia, Poutasi and Tuasivi respectively. Mean BMIs followed the same pattern. By contrast, WHR varied little between locations. Even in subjects aged 25-34 years, more than 50% of women in all locations, and 45% of urban men were obese. Increasing physical activity in men, but not women, was associated with lower mean BMI. Increasing education level and job status were associated with increasing BMI but these relationships were significant only in men. Multivariate analysis showed age, location (urban), occupation (high status, women), and in men, physical inactivity, to be independently associated with increased risk of obesity. Prevalence of obesity increased dramatically between 1978 and 1991 in all locations, but especially in Tuasivi, where in males the increase was 297% and in females 115%. There was a rightward shift in the distribution of body mass index in both sexes and all locations. These extreme increases in the prevalence of obesity, even in young adults, over the relatively short 13-year study period suggest an increasing burden of chronic diseases facing Western Samoa in the future, and emphasize the need for effective intervention to bring about lifestyle modification.