Body fatness distribution is a useful epidemiological and clinical marker of health risk among European and other populations. Prevalence of obesity among adults is rising in many parts of Malaysia, and it is important to understand the extent to which fat patterning is robust across different age groups and between the sexes. This analysis examines fatness and fat distribution in rural Sarawakian adults aged 20 to 80 years to determine the extent to which fat patterning varies by sex and age. Principal component analysis of five skinfolds (biceps, triceps, subscapular, suprailiac and medial calf) shows upper body-lower body fat distribution as contributing most to within-group variation in the sum of five skinfolds for both males and females. When divided into younger and older age groups, clear differences were identified. For the males, while absolute fatness does not change with age, there is a change in fat patterning, with a trunk-extremity component disappearing, and a trunk-lower body pattern persisting. Females experience a decline in subcutaneous fatness across age groups, and while the most important component of fat distribution, trunk to lower body subcutaneous fatness, the same for younger and older women, the second component is different, with upper limb-lower body distribution in the younger age group being replaced with upper to lower trunk distribution. The similarities in fat patterning among males and females suggest that the use of fat patterning indices in this Malaysian population need not be sex-specific, but age group- and sex-dependent differences in the second principal component indicate that they should be used with caution, since the relationships between fat patterning and mortality are still poorly understood among Malaysian populations.
This paper reports findings of a cross-sectional anthropometric survey of 447 men and 564 women aged > 18 years of the Iban tribe in rural Sarawak. The percentage of each approximately 10 year cohort with body mass index (BMI: kg/m2) < 18.5 increased progressively with age > 40 years in both sexes. BMI and arm-muscle plus bone cross-sectional area (AMBA) were influenced significantly by reported single symptoms in men and two concurrent symptoms in women. Sensitivity of BMI < 18.5 for identifying those reporting symptoms of illness was 21% in men and 29% in women. Independently of illness effects, values of stature, BMI and AMBA in men, and stature alone in women, were significantly greater in those farming plots with the shortest time left fallow, suggesting their comparative success. The BMI of men may reflect primarily their economic activities, while that of women their experience of illness; the AMBA may also be a better overall index of health than BMI in this population.
Classifications of adult low energy nutritional status based on the Quetelet or body mass index (weight/height2) have often assumed independence of age and sex. This paper reports findings of a study of 447 men and 564 women aged over 18 years and belonging to the Iban tribe of central Sarawak, East Malaysia. BMI and fat-free mass fell markedly in both sexes, and fat mass in women but not men, after about 40 years of age. In men over age 40, and women aged 18-40, BMI was sensitive to reported morbidity. For subjects aged over 40 years, BMI was related to morbidity independently of age effects in men, and to age alone in women. These findings suggest that the functional significance of low BMI differs between the sexes and with age.