title: Socioeconomic status, body size and physical activity of adults on Rarotonga, the Cook Islands.
abstract: Much of the secular trend toward increased body size among populations in the Pacific Region has been attributed to the processes of economic modernization and socioeconomic change. The primary objective of the present analysis was to examine the relationships between socioeconomic factors and stature, weight, body mass index and physical activity level of adult Cook Islanders living a largely modernized lifestyle in the Pacific Region. In a cross-sectional study of physical activity, body size and socioeconomic status, a volunteer sample of 345 Cook Islanders aged 20-65 years was obtained from the total adult population of Rarotonga, and measured at six out-patient clinics. Stature, weight, body mass index (BMI), physical activity level and age were calculated by sex and occupational category, years of education, island of birth and number of years lived on Rarotonga, respectively, using SPSSPC for Windows. Stepwise multiple regression was used to examine the relationships between stature, weight, BMI, PALweekday (a measure of physical activity level), age and non-linear functions of age, and the socioeconomic variables. These analyses indicate that the secular trend in stature is a function of the relative level of modernization on Rarotonga relative to other Cook Islands, and with level of education. These factors associate differently among males and females, the secular trend among males appearing to be a general phenomenon in response to lifestyle change associated with life on Rarotonga, while among females the trend is a function of lifestyle change associated with education and independent of island of origin. The trend toward increasing body fatness is also different for males and females. Weight declines with age for both men and women, in a linear way for the males, but in a non-linear fashion for the females. Body weight is also greater among those males in more skilled and professional occupations than among those with less-skilled professions. For the women, weight is independent of occupation category. Physical activity patterns of modernizing adult Cook Islanders show no relationships with socioeconomic variables for the males, but while older women are less active, those born on Rarotonga are less active than those born elsewhere in the Cook Islands. The number of years spent on Rarotonga shows no significant relationships with any of the physical measures, or with physical activity level. This is likely to be as much a function of small sample size as a lack of effect. Although declines in energy expenditure with increasing age have been demonstrated for both males and females in various populations around the world, on Rarotonga this holds true for females and not males, indicating that physical activity declines with increasing age in modernizing societies do not occur in uniform fashion.
authors.affiliation: Institute of Biological Anthropology, University of Oxford, UK. stanley.ulijaszek@bioanth.ox.ac.uk
authors.forename: S J
authors.initials: SJ
authors.lastname: Ulijaszek
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001824:Body Constitution / Q000208:ethnology*; D001827:Body Height; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D004522:Educational Status; D005006:Ethnicity; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011114:Polynesia; D015995:Prevalence; D012044:Regression Analysis; D012737:Sex Factors; D012959:Socioeconomic Factors