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Stature, weight, arm circumference, triceps skinfold and estimated mid-arm muscle circumference were compared in schoolchildren, 6 to 14 years of age, in 1968 and 1978. The children were resident in a rural Zapotec-speaking community in the Valley of Oaxaca in southern Mexico. There were no differences in stature, weight and arm circumference over the ten-year period. Triceps skinfold and estimated mid-arm muscle circumference showed small, significant changes. Multiple classification analysis, adjusting for age and sex variation, indicated that schoolchildren in 1978 were slightly heavier and fatter, but also slightly shorter and less muscular than children in 1968. Results of this follow-up survey indicate little improvement in the growth status of rural Zapotec schoolchildren over ten years from 1968 to 1978, and are consistent with adult stature data which show little evidence of secular change over 80 years.

Adult stature and the age at menarche among individuals from Zapotec-speaking communities in the Valley of Oaxaca in southern Mexico are considered in a secular perspective. Four sets of observations are utilized: 1) adult stature in males and females from five rural communities; 2) age at menarche in adult women and school girls from a single rural community; 3) earlier studies of adult stature in the Valley of Oaxaca; and 4) estimated stature from long bones excavated in various archaeological sites in the Valley of Oaxaca. There were no significant differences among the five communities for stature; hence, the data were pooled for analysis and comparison. Results of linear regression of stature and stature adjusted for the estimated effects of aging after 30 years of age on year of birth indicate negligible secular changes in either sex. Comparisons with statures from earlier surveys, the earliest dates to 1899, also indicate negligible changes. When adult women are grouped according to age, there are no differences in mean ages at menarche between the older and younger women. Mean age at menarche for the total adult sample is 14.53 +/- 0.08 years, which compares favorably with the probit estimate for school girls, 14.70 +/- 0.32 years. These results thus suggest virtually no secular change in adult size and maturity of the Zapotec-speaking population in the Valley of Oaxaca over the past 80 years. Differences in stature between contemporary populations and estimated statures from long bones from several archaeological sites in Oaxaca are small, and thus suggests little secular change over the past one to two-thousand years.

Assortative mating for age and several anthropometric characteristics is considered in a sample of 68-70 husband-wife pairs from a rural Zapotec-speaking community in the Valley of Oaxaca in southern Mexico. Conditions in the community with a population of approximately 1700 indicate chronic, mild-to-moderate undernutrition as reflected in high infant mortality rates, smaller body size of school children, and delayed biological maturation. Phenotypic assortative mating, as expressed in husband-wife correlations, is significant for age (r = 0-96), stature (r = O-35) and grip strength (r = 0-29), but is not significant for body weight (r = 0-01), arm circumference (r = 0-07), the estimated midarm muscle circumference (r = 0-003), Quetelet's index (r = 0-02), and the ponderal index (r = 0-11). Controlling for age of husband and wife reduces the correlations for stature (r = 0-24) and grip strength (r = 0-12), but increases those for arm circumference (r = 0-21) and estimated midarm muscle circumference (r = 0-16). Grouping the spouses into younger (under 30 years of age) and older (30 years and older) results in significant spouse correlations for age, stature, arm circumference and estimated midarm muscle circumference in the younger group and for only age and fatness in the older group.

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