High altitude and early childhood growth retardation: new evidence from Tibet.

OBJECTIVE: To assess possible effect of high altitude on early childhood growth in Tibet.

METHOD: A cross-sectional survey on child health and nutrition was conducted in Tibet with stratified multistage cluster random sampling technique. Height and weight status of Tibetan children <36 months of age was measured. A questionnaire was administered to mothers of children for information on family background, child feeding practice and health care and maternal care. A total of 1458 children with complete information were used for analysis. A logistic regression model was used to control for selected potential confounding factors and then observed altitude effect on growth of Tibetan children.

RESULTS: Positive association of stunting with altitude was observed for each age group, even after controlling for selected potential affecting factors. Children above 3500 m had two to six times risk of getting stunting compared with those at 3000 m when socioeconomic and other factors were controlled. Effect of altitude on underweight was observed only among children <24 months old and significant increase in odds ratio appeared only above 4000 m after controlling for those confounding factors. Indicator of wasting was not related to altitude.

CONCLUSIONS: Altitude might result in a delay in height of younger Tibetan children, independent of socioeconomic and other factors operating through nutrition and disease, and took adverse effect persistently through birth to 3 years old. Its adverse effect on weight could be limited. For comparison and assessment of nutritional status of Tibetan children, the effect of altitude on growth should be taken into account.