Ethnic differences in spirometry measurements in China: Results from a large community-based epidemiological study.

BACKGROUND AND OBJECTIVE

No previous studies have examined differences in spirometry measurements among ethnic populations in China, and factors which may influence ethnic differences are unclear. Our study aimed to investigate whether forced expiratory volume in 1 s (FEV ) and forced vital capacity (FVC) differ among Han Chinese and other ethnic minorities in China.

METHODS

We recruited 7137 individuals aged 35-70 years from four areas of China inhabited by ethnic minority groups between 2007 and 2009. We conducted spirometry tests for all available participants, and compared FEV and FVC among Uygur, Hui, Mongolian, Dai and Han Chinese ethnicities, using nonlinear multiplicative regression models.

RESULTS

A total of 2005 healthy never-smokers were enrolled in the analysis. For all ethnicities, spirometry values increased with height and decreased with age; FEV and FVC were consistently higher in males than in females. Compared with Han Chinese, FEV was 4.42% (95% CI: 2.11-6.78%) higher in Mongolians, 4.08% (95% CI: 1.33-6.76%) lower in Uygurs, 4.39% (95% CI: 1.33-7.35%) lower in Hui people and 4.72% (95% CI: 1.80-7.55%) lower in Dai people, after adjusted for potential confounders including height, age, sex and place of residence. We observed similar differences for FVC.

CONCLUSIONS

We detected significant differences in spirometry measurements among ethnic populations in China. Such differences cannot be fully explained by demographic, anthropometric or socioeconomic factors, but may also be attributed to genetic background as well as indoor and outdoor environmental exposures that need further investigation.