Objective To investigate the long-term effects of air pollution on hypertension and heart disease among middle-aged and elderly people, and differentiate the effects with regional urbanization levels in China.
Methods We used the data on the prevalences of hypertension and heart disease of 17 679 respondents in 124 prefecture-level cities reported in the 2013 China Health and Retirement Longitudinal Study (CHARLS) and measured three-year (2010-2012) average concentrations of inhalable particulate matter (PM10), sulfur dioxide (SO2), and nitrogen dioxide (NO2) in the prefecture-level cities. The urbanization level was defined by urbanization rate. We utilized generalized linear mixed-effects models to analyze the differences in the effects of air pollution on the prevalences of hypertension and heart disease in areas with different urbanization levels.
Results The average annual concentrations of PM10, SO2, and NO2 in the studied 124 prefecture-level cities were 80, 36, and 31 μg/m3, respectively. There were 68.5% of the cities exceeding the national grade Ⅱ standards of PM10. The prevalence rates of hypertension and heart disease were higher in areas with high urbanization level (27.4%, 12.3%) than in areas with middle urbanization level (23.1%, 8.9%) and low urbanization level (19.2%, 6.9%) (P < 0.05). There were interactions between the exposure to atmospheric PM10/NO2 and urbanization rates on the prevalences of heart disease in middle-aged and elderly people. The effect of the exposure to air pollutants was largest in areas with low urbanization level (PM10:OR=2.169, 95% CI:1.275-3.691; NO2:OR=1.817, 95% CI:1.100-3.000).
Conclusion The effects of air pollution on hypertension and heart disease among middle-aged and elderly people are varied by urbanization levels in China. A greater impact is found in areas with a lower urbanization level.
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