Abstract
BACKGROUND: Health effects of air pollution on anaemia have been scarcely studied worldwide. We aimed to explore the associations of long-term exposure to ambient air pollutants with anaemia prevalence and haemoglobin levels in Chinese older adults. METHODS: We used two-level linear regression models and modified Poisson regression with robust error variance to examine the associations of particulate matter (PM) and nitrogen dioxide (NO(2)) on haemoglobin concentrations and the prevalence of anaemia, respectively, among 10,611 older Chinese adults enrolled in World Health Organization (WHO) Study on global AGEing and adult health (SAGE) China. The average community exposure to ambient air pollutants (PM with an aerodynamic diameter of 10 μm or less (PM(10)), 2.5 μm or less (PM(2.5)), 1 μm or less (PM(1)) and nitrogen dioxide (NO(2))) for each participant was estimated using a satellite-based spatial statistical model. Haemoglobin levels were measured for participants from dried blood spots. The models were controlled for confounders. RESULTS: All the studied pollutants were significantly associated with increased anaemia prevalence in single pollutant model (e.g., the prevalence ratios associated with an increase in inter quartile range in three years moving average PM(10) (1.05; 95% CI: 1.02-1.09), PM(2.5) (1.11; 95% CI: 1.06-1.16), PM(1) (1.13; 95% CI: 1.06-1.20) and NO(2) (1.42; 95% CI: 1.34-1.49), respectively. These air pollutants were also associated with lower concentrations of haemoglobin: PM(10) (-0.53; 95% CI: -0.67, -0.38); PM(2.5) (-0.52; 95% CI: -0.71, -0.33); PM(1) (-0.55; 95% CI: -0.69, -0.41); NO(2) (-1.71; 95% CI: -1.85, -1.57) respectively. CONCLUSIONS: Air pollution exposure was significantly associated with increased prevalence of anaemia and decreased haemoglobin levels in a cohort of older Chinese adults.