Background
Indoor air pollution is an important risk factor affecting health of the respiratory system. Studies on indoor air pollution in China are mostly limited to the central and eastern regions, and there are few studies in the rural areas of northwest China.
Objective
To explore the influencing factors of lung ventilation function and its relationship with indoor air pollution in rural areas of Gansu Province based on a cross-sectional investigation.
Methods
A total of 399 subjects were selected from four villages in Baiyin and Yuzhong of Gansu Province. Questionnaires were used to collect demographic information, lifestyle, disease history, fuel use, and other information, and physical and functional tests were ordered such as height, weight, and lung function. The Indoor Air Pollution (IAP) exposure index was calculated based on smoking, fuel type, and weekly ventilation. IAP > 5 was defined as a high level of indoor air pollution. Lung function indexes included forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC, forced vital capacity as a percentage of predicted value (FVC%), and forced expiratory volume in the first second as a percentage of predicted value (FEV1%), which were used to determine pulmonary ventilation dysfunction. Logistic regression model was used to evaluate the relationship between indoor air pollution and pulmonary ventilation function, and subgroup analysis was further conducted according to home address and BMI , in order to identify the high-risk population of pulmonary ventilation dysfunction.
Results
The mean age of the subjects was (56.75±7.31) years old; 155 subjects (38.85%) had normal pulmonary ventilation function, and the other 244 subjects (61.14%) had impaired pulmonary ventilation function; about 89.97% of the subjects were exposed to high level of indoor air pollution (IAP > 5). We found that IAP > 5 ( OR=2.327, 95%CI: 1.089-4.974) and use of bituminous coal as the main heating fuel in winter (OR=3.467, 95%CI: 1.197-10.037) increased the risk of pulmonary ventilation dysfunction after adjusting for age, BMI, residence, gender, smoking, drinking, and cardiovascular disease. The subgroup analysis results showed that no ventilation in the living room/bedroom (OR=3.460, 95%CI: 1.116-10.268) increased the risk of pulmonary ventilation dysfunction in Baiyin. Heating with coal stoves and Chinese Kang in the bedroom (OR=2.092, 95%CI: 1.030-4.247) and cooking in the bedroom in winter ( OR =2.954, 95% CI : 1.046-8.344) also increased the risk of pulmonary ventilation dysfunction in the residents with BMI≤24 kg·m−2. IAP > 5 ( OR=3.739, 95%CI: 1.147-12.182) was associated with a significantly increased risk of pulmonary ventilation dysfunction in the BMI > 24 kg·m −2 subgroup.
Conclusion
The pulmonary ventilation function of rural residents in Gansu is poor, which is negatively correlated with indoor air pollution. Coal use, overweight, cooking in bedroom, and use of coal stoves and Chinese Kang for heating may increase the risk of pulmonary ventilation dysfunction, while room ventilation is a beneficial factor.
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