Aging in selected anthropometric dimensions in a rural Zapotec-speaking community in the Valley of Oaxaca, Mexico

Stature, weight, arm circumference, triceps skinfold and grip strength were measured in a cross-sectional sample of 116 men and 113 women, 20-82 years of age, from a rural Zapotec-speaking community in the Valley of Oaxaca in southern Mexico. Mortality statistics, growth, and maturity status of children in the village are indicative of chronic mild-to-moderate under-nutrition. Adult Zapotecs are smaller, lighter and leaner than reference data for better-off populations. Sex differences are clearly evident for stature, fatness and grip strength. Body weight shows little sex difference after 40 years of age. Estimated mid-arm muscle circumference, however, is larger in males at all ages except over 60 years. Weight, arm circumference, the triceps skinfold and estimated muscle circumference are generally lowest in women 20-39 years, most likely reflecting the depletion of energy stores due to successive pregnancies and lactation. When stature is adjusted for the estimated loss associated with aging, there is suggestion of a secular increase in males but not in females. Sampling variation, small numbers at the older ages, and perhaps selective out migration must be considered in evaluating possible secular effects. Although absolute grip strength of adult Zapotecs is less than that of better-off samples of adults, grip strength per unit body weight is similar.