Weight-for-height and mid-upper-arm circumference should be used independently to diagnose acute malnutrition: policy implications

The purpose of this study was to test the hypothesis that muscle fiber type is related to obesity. Fiber type was compared 1) in lean and obese women, 2) in Caucasian (C) and African-American (AA) women, and 3) in obese individuals who lost weight after gastric bypass surgery. When lean (body mass index 24.0 +/- 0.9 kg/m(2), n = 28) and obese (34.8 +/- 0.9 kg/m(2), n = 25) women were compared, there were significant (P < 0.05) differences in muscle fiber type. The obese women possessed fewer type I (41.5 +/- 1.8 vs. 54.6 +/- 1.8%) and more type IIb (25.1 +/- 1.5 vs. 14.4 +/- 1.5%) fibers than the lean women. When ethnicity was accounted for, the percentage of type IIb fibers in obese AA was significantly higher than in obese C (31.0 +/- 2.4% vs. 19.2 +/- 1.9%); fewer type I fibers were also found in obese AA (34.5 +/- 2.8% vs. 48.6 +/- 2.2%). These data are consistent with the higher incidence of obesity and greater weight gain reported in AA women. With weight loss intervention, there was a positive relationship (r = 0.72, P < 0.005) between the percentage of excess weight loss and the percentage of type I fibers in morbidly obese patients. These findings indicate that there is a relationship between muscle fiber type and obesity.

Despite broad agreement that severe malnutrition contributes to child mortality in developing countries and that malnutrition has a physiologically synergistic relationship with morbidity, evidence of an epidemiologic synergism has been lacking. Also, the literature provides conflicting evidence concerning the existence of elevated mortality among children with mild to moderate malnutrition. A review of published population-based studies of anthropometry-mortality relationships was undertaken to clarify these relationships. Six studies with the relevant data were reanalyzed to test for synergism and elevated mortality in mild to moderate malnutrition. The results demonstrate that mortality increases exponentially with declining weight for age. This effect is consistent across studies and there is no apparent threshold effect on mortality. The primary difference across studies is in baseline levels of mortality, which determine the quantitative impact of malnutrition on mortality in a population. These results indicate that mild to moderate malnutrition is associated with elevated mortality and that there is an epidemiologic synergism between malnutrition and morbidity. This previously undemonstrated finding has significant implications for child survival policies and research.