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Rationale: Spirometry reference equations that are derived from a large, nationally representative general population are warranted in China, and the impact of using prebronchodilator (pre-BD) and post-BD spirometry reference values has yet to be assessed in Chinese populations. Objectives: To present the pre-BD and post-BD spirometry reference values for Chinese adults using the China Pulmonary Health (CPH) Study. Methods: A reference population of 17,969 healthy, nonsmoking participants in the CPH Study was used to calculate the pre- and post-BD reference values for FEV1, FVC, and FEV1/FVC ratio. Pre- and post-BD reference values were applied to the entire CPH population (N = 50,991) to illustrate the divergence between the use of different references in determining disease prevalence and severity grading. Measurements and Main Results: The prevalences of airflow limitation were 5.36% using the pre-BD reference and 8.02% using the post-BD reference. Individuals who had a post-BD FEV1/FVC ratio lower than the post-BD reference value but higher than the pre-BD reference value were found to have significantly higher rates of self-reported respiratory symptoms and significantly lower values on spirometry indicators than those whose post-BD FEV1/FVC ratio was greater than the post-BD reference value. An additional 3.51% of participants were identified as having grade II–IV chronic obstructive pulmonary disease using the post-BD FEV1 predicted values. Conclusions: This study generated and applied pre- and post-BD spirometry reference values in a nationally representative Chinese adult population. Post-BD reference values may serve as an additional criterion in identifying individuals at risk for obstructive pulmonary diseases, and their diagnostic and prognostic values should be further investigated. [ABSTRACT FROM AUTHOR]

Background Exposure to air pollution, a leading contributor to the global burden of disease, can cause economic losses. Driven by clean air policies, the air quality in China, one of the most polluted countries, has improved rapidly since 2013. This has enabled a unique, quasi-experiment to assess the economic impact of air pollution empirically. Methods and findings Using a series of nation-scale longitudinal surveys in 2011, 2013, and 2015, we first examined the questionnaire-based medical expenditure changes before and after the policy intervention for air pollution. Using a state-of-the-art estimator of the historical concentration of particulate matters with diameter less than 2.5 [mu]m (particulate matter (PM).sub.2.5 ), we further quantified the association between household medical expenditure and PM.sub.2.5 using mixed-effect models of the repeated measurements from 26,511 households in 126 cities. Regression models suggest a robust linear association between reduced PM.sub.2.5 and saved medical expenditures, since the association did not vary significantly across models with different covariate adjustments, subregions, or subpopulations. Each 10 [mu]g/m.sup.3 reduction in PM.sub.2.5 was associated with a saving of 251.6 (95% CI: 30.8, 472.3; p-value = 0.026) Yuan in per capita annual medical expenditure. However, due to limitations in data quality (e.g., self-reported expenditures), and imperfect control for unmeasured confounders or impact from concurrent healthcare reform in China, the causality underlying our findings should be further confirmed or refuted. Conclusion In this study, we observed that compared with the PM.sub.2.5 reduction in 2013, the PM.sub.2.5 reduction in 2017 was associated with a saving of 552 (95% CI: 68, 1036) Yuan / (person x year), or approximately 736 billion Yuan (equivalent to 111 billion US dollar) per year nationally, which is equivalent to approximately 1% of the national gross domestic product of China., Author(s): Tao Xue 1,*, Tong Zhu 2,*, Wei Peng 3, Tianjia Guan 4, Shiqiu Zhang 5, Yixuan Zheng 6, Guannan Geng 7, Qiang Zhang 8 Introduction Long-term exposure to ambient [...]

Background: Exposure to air pollution is associated with several chronic diseases and subclinical processes that could subsequently contribute to physical disability. However, whether and to what extent air pollution exposure is associated with objective measures of physical functioning remains understudied.Methods: We used longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS) and included 10 823 participants who were surveyed at least twice. Annual average exposure to fine particulate matter (PM2.5) was assessed using a state-of-the-art estimator. Physical functioning was assessed with 4 objective tests covering hand-grip strength, balance, repeated chair stands, and gait speed. Mixed-effects models with participants as a random term were used to estimate associations with multiple adjustments.Results: We found a significant and robust association between exposure to increased PM2.5 and the reduction in hand-grip strength and balance ability. Each 10 μg/m3 increase in annual averaged concentrations of PM2.5 was associated with a 220-g (95% confidence interval [CI]: 127, 312 g) reduction in hand-grip strength per 60 kg of body weight and a 5% risk (95% CI: 2, 7) of reduced balance ability. The estimated effect of each 10 μg/m3 increase in PM2.5 on hand-grip strength and balance ability was equivalent to the effect of aging (1.12 [95% CI: 0.76, 1.48] and 0.98 [95% CI: 0.50, 1.50] years, respectively).Conclusions: PM2.5 may be differentially associated with various dimensions of physical functioning. Improving air quality can prevent physical disability. [ABSTRACT FROM AUTHOR]