Urban–rural disparities in the association between long-term exposure to high altitude and malnutrition among children under 5 years old: evidence from a cross-sectional study in Tibet

Abstract

Objective: To assess urban-rural disparities in the association between long-term exposure to high altitude and malnutrition among children under five years old. Design: A three-stage, stratified, cluster sampling was used to randomly select eligible individuals from July to October 2020. The data of participants, including demographic characteristics, altitude of residence, and nutritional status, were collected via questionnaire and physical examination. Setting: Tibet, China. Participants: Children under five years old in Tibet. Results: 1,975 children under five years old were included in this study. We found that an additional 1,000 meters (m) increase in altitude was associated with decreased Z-scores of height for age (HFA) (β=-0.23, 95%CI: -0.38 to -0.08), Z-scores of weight for age (WFA) (β=-0.24, 95%CI: -0.39 to -0.10). The odds ratios (ORs) for stunting and underweight were 2.03 (95%CI: 1.51 to 2.73) and 2.04 (95%CI: 1.38 to 3.02) per 1000 m increase in altitude respectively; and ORs increased rapidly at an altitude above 3,500 m. The effects of long-term exposure to high altitudes on the prevalence of underweight in rural children were higher than that in urban children (P<0.05). Conclusions: High altitude exposure is tightly associated with malnutrition among children under five years old. Improving children’s nutrition is urgently needed in areas above 3,500 m, especially in rural ones.

Geographical altitude and stunting among children aged under 5 years in India

“…First, geographical altitude is a key factor, aligning with previous research showing higher stunting prevalence at higher altitudes 8–13. The harsher climate and terrain at higher altitudes probably pose challenges to implementing nutrition interventions.…”

“…Several studies from high-altitude regions in other countries like Ethiopia, Argentina, Peru and Tibet have found that living at higher elevations is associated with increased risk of stunting and other forms of child undernutrition 8–13. For instance, an analysis in Tibet by Li et al 13 found that children at 3000 m had 60% higher odds of stunting compared with those at 1500 m. In Ethiopia, children in higher altitudes showed a higher risk of stunted growth, with prevalence peaking at 47% in the highlands compared with 39% in the lowlands.…”