Association of household air pollution with glucose homeostasis markers in Chinese rural women: Effect modification of socioeconomic status

Abstract

BackgroundSocioeconomic status (SES) was a crucial influencing factor of household air pollution (HAP). However, few studies have explored the potential effect modification of SES on the associations of HAP with type 2 diabetes mellitus (T2DM) and glucose homeostasis. MethodsA total of 20900 participants were obtained from the Henan Rural Cohort. HAP reflected by cooking fuel type and cooking duration was assessed via questionnaire. SES was evaluated by two dimensions: educational level and average monthly income. Associations of cooking fuel type, cooking duration with T2DM and glucose homeostasis indices (insulin, fasting plasma glucose (FPG), and HOMA-β) were assessed by the generalized linear model. Analyses were also conducted in different SES groups to explore the potential effect modification. ResultsSignificant negative association of cooking fuel type and cooking duration with T2DM, FPG, and HOMA-β was not observed. However, cooking with solid fuel and long-duration cooking were associated with decreased insulin level in women, and the adjusted coefficients were − 0.35 (95% confidence interval (95% CI): − 0.53, − 0.17) and − 0.36 (95% CI: −0.50, −0.21), respectively. Results from stratified analyses showed that these associations were more prominent in women with low average monthly income, with corresponding coefficient of − 0.57 (95% CI: −0.77, −0.37) for cooking with solid fuel and − 0.34 (95% CI: −0.52, −0.16) for long-duration cooking. Among women with low average monthly income, the largest decreased insulin level was observed in those who cooked with solid fuel, long-duration and poor kitchen ventilation, while the negative association of cooking fuel type and cooking duration with insulin level was slightly alleviated in the good kitchen ventilation group. ConclusionsLow average monthly income aggravated the negative association of HAP and insulin level among rural women, while improving kitchen ventilation may be a practical intervention. Trail registrationThe Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July, 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375.