Growth patterns in adverse environments.

The triple-logistic pattern of human growth in linear dimensions is probably one of the most recognizable models within human biology. The fact that postnatal somatic growth occurs in three phases (infancy, childhood, adolescence) creates opportunities for the individual expression of this genetically directed, but environmentally modified, phenomenon. The impact of the environment works to alter the duration and intensity of critical stages within the total process resulting in individual patterns that can differ radically from the general pattern. However, the constancy of the general pattern is so fixed that its presence in children is taken as a reflection of good health. Departures from that pattern are recognized as reflecting ill health. While the cessation of growth in response to an acute attack is uniformly dramatic, the gradual response to chronic adverse stimuli is less easily predicted and interpreted. For example, in chronic scenarios the loss of centile position that precedes the eventual establishment of normal increments can be viewed as either a poor or a good growth response, as either maladaptive or adaptive, as either poor health or good health. This article reviews such growth patterns in urban South African children exploring the relationship between environment and growth outcome.