Exposure to ambient PM_2.5 associated with overall and domain-specific disability among adults in six low- and middle-income countries

Background Exposure to particulate matter pollution is associated with various cardiopulmonary diseases, which are closely related with disability. The direct relationship between air pollution and disability, however, has not been fully explored. Methods We used data from 45,625 participants in the Study on global AGEing and adult health in six low- and middle-income countries. The 12-item version of the World Health Organization Disability Assessment Schedule (WHODAS 2.0) was used to measure the disability with six domains (cognition, mobility, self-care, getting along, life activities, and participation in society). Participants' community addresses were used to estimate annual concentration of PM_2.5 using satellite data. We used linear mixed models to examine the effects of PM_2.5 on overall and domain-specific WHODAS scores. Results Exposure to PM_2.5 was significantly associated with greater disability score (a higher score implies a greater disability); each 10 μg/m³ increase corresponded to 0.72 (95% CI: 0.22, 1.22) increase in overall disability score. Compared with low PM_2.5 level (< 14.33 μg/m³), moderate (14.33–27.83 μg/m³) and high exposure levels (> 27.83 μg/m³) were associated with 3.43 (95% CI: 1.43, 5.43) and 3.72 (95% CI: 1.59, 5.86) increase in disability scores. Among the six domains, cognition, mobility and getting along were found to be associated with PM_2.5. Stratified analyses found that women and older subjects were more sensitive to this effect. Conclusion Exposure to ambient PM_2.5 might be one risk factor of disability in the low- and middle-income countries, women and older adults are the vulnerable population; and among the six domains, cognition, mobility and getting along are more relevant to this effect.