Patterns of adult weight and fat change in six Solomon Islands societies: a semi-longitudinal study.

Semi-longitudinal changes with aging in weight, height, arm circumference, and subscapular and triceps skinfold circumference are presented for adult males and females in 6 different populations in the Solomon Islands and Papua New Guinea, which have differed dramatically in their exposure to modern industrialized societies over the past decade. Those groups who remain less acculturated show little or no evidence of a secular trend in adult body size and women in these groups lose weight through their childbearing years and into old age. Men lose less. In the more acculturated groups, weight gain due to increases in fatness have already become the norm for all female cohorts, and most male cohorts. In most groups there are significant losses in muscle mass after age 40 in men, regardless of acculturation status, which were not detected in women. Because changes in diet have been more extreme for men than women in the more acculturated groups, and childbearing and nursing patterns have not changed, the more consistent and significant shift in female fat changes with age is most likely due to a sharp change in activity pattern, in addition to dietary change.