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.
To evaluate the effect of different methods (plateau or back extrapolation) of calculating total body water (TBW) from deuterium dilution in an environment characterised by high water turnover. The back extrapolation model is assumed to be more accurate when water turnover is high.
The effects of population pressure on agricultural sustainability in the delicate tropical and subtropical ecosystems have often been thought to explain high prevalence rates of malnutrition in rural South-East Asia. However, recent studies in rural Sarawak suggest that processes of modernisation have resulted in increased variations in energy nutritional status in adults. A contributory factor may be consumption of the areca nut (Malay pinang, of the palm Areca catechu). This is thought to influence energy balance through effects on appetite and resting metabolic rate. Body mass index (BMI, kg/m2) data for 325 Iban men and 438 non-pregnant Iban women, measured in 1990 and again in 1996, have been analysed in relation to areca use, smoking behaviour, socio-economic status, and reported morbidity. Body composition derived from skinfold thickness measurements for 313 men and 382 women was also analysed. The results suggest that use of areca nut is associated with significantly lower age-related increments in BMI and percentage body fat in women after allowing for age, smoking, reported morbidity, and confounding socio-economic factors. Therefore, the impact of recent economic and social development seen in rising prevalences of 'over-nutrition' may be modulated by use of the areca nut.
The areca nut is chewed by many of the world's population, mainly in South and Southeast Asia. Anthropometric data for 458 Sarawaki adults aged over 24 years, measured both in 1990 and in 1996, were examined in relation to use of tobacco and areca nut. Compared to non-smokers, smoking men were significantly taller and slightly (not significantly) thinner in both years, while smoking women were thinner in 1990 and slightly (not significantly) thinner in 1996. In both sexes there was an increase in the mean and range of body mass index (BMI, W/H2) over the 6-year interval. Smoking women showed a significantly smaller increment in BMI after allowing for areca nut use, which was associated with a similar trend, and this finding depended on including areca use in the model. The trend for men was similar. Possible effects of areca use could reflect variation in 'affluence' or conservatism, or appetite suppression. However, resting metabolic rate in 54 men and 70 women aged 24-60 years was associated with areca use. This association appeared to be mediated by the maximum room temperature of the 24 h preceding measurement. In women, a significant curvilinear association of RMR with maximum temperature was found in users of areca nut but not in non-users. In men, RMR was 7% higher (p < 0.05) in users of areca nut than in non-users, after allowing for age, height, weight, the sum of four skinfold thicknesses, and haemoglobin, but the association with maximum temperature was similar in both groups. It is speculated that constituents of areca nut modulate thermoregulatory pathways, resulting in prolonged temperature-dependent and hyperthermic heat production in this population; that males are more responsive to this effect than females; and that by this mechanism, and possibly also through centrally mediated effects on appetite for food, areca use could contribute to long-term variation in energy balance represented by change in BMI.