The secular trend in size and maturational timing and its implications for nutritional assessment.

For most westernized countries there has been a marked intergenerational increase in size and a decrease in the age at menarche, both interrupted or temporarily reversed during economic disruption or war-time deprivation. In some Third World countries such secular trends have not yet occurred or there have been actual decreases in body size. The presence or absence of secular trends can be used as a form of nutritional surveillance, and in the westernized world the magnitude of secular trends necessitates continual updating of dimensional and maturational standards used in nutritional appraisal.