Ecological Study of Community-Level Factors Associated With Chronic Mountain Sickness in the Young Male Chinese Immigrant Population in Tibet

BACKGROUND Chronic mountain sickness (CMS) is a complex medical and public health problem that seriously affects highland immigrants. This study investigated relationships between community-level factors and CMS. METHODS In this ecological study, data on age- and ethnicity-standardized CMS rates, community factors, and controlling variables were obtained from 2009-2010 surveys of 108 Chinese highland military units. Associations among variables were examined using correlation tests, analyses of covariance, and logistic regression. RESULTS The rate of CMS ranged from 1.25% to 36.58% (mean: 14.65%, standard deviation: 8.15%) among military units. Partial correlation tests indicated that medicine expenditure was strongly negatively correlated with CMS (r = -0.267, P = 0.005). Analyses of covariance indicated that communities with oxygen-generating systems had lower CMS rates (F = 9.780, P = 0.002), whereas urban location (F = 5.442, P = 0.022) and construction duty (F = 4.735, P = 0.011) were associated with higher CMS rates. The multiple logistic model showed that medicine expenditure (OR = 0.897, P = 0.022), oxygen-generating system (available vs unavailable: OR = 0.827, P = 0.020), community type (urban vs rural: OR = 1.228, P = 0.019), and occupation (construction vs logistics: OR = 1.240, P = 0.029) were significantly associated with CMS. CONCLUSIONS We identified community-level, health-related factors that were associated with CMS among young male immigrants. To alleviate the burden of CMS in these highland immigrant populations, further investment should be made in medicine and oxygen-generating systems, and preventive interventions should be implemented among construction workers. Further research should investigate the effects of urbanization on CMS development.