[Comparative study of height and age at menarche according to the socioeconomic level in Venezuela].

This is a retrospective study based on growth and development data published in Venezuela by various authors in the period 1936-1978. The data on height for males of the middle and high socioeconomic strata show growth curves which are very similar to the standards for British children. Likewise, the girls of the same socioeconomic condition follow the British standards, but only up to about 10-12 years of age. After that age, the girls studied by the Venezuelan authors, show a pattern of early maturation with a corresponding lower adult height compared with their British counterparts. There were differences in the growth curves according to the socioeconomic strata. These differences were more marked in the girls data. A secular increase for height was discerned, from the published data, in all socioeconomic strata and in both sexes. The data on sexual maturation showed a tendency for progressively early menarche in Venezuelan girls. These changes in growth in height and age of menarche were more notorious and came about at an earlier age in the upper socioeconomic strata. They were less marked, not constant, and came about later in the lower socioeconomic groups. The secular changes in height and sexual maturation apparent from these data, could be explained by an improvement in the environmental conditions, especially nutrition and hygiene of the population, and also be genetic heterosis from European immigration and with improvement in communications.