Associations between Ambient and Indoor PM2.5 Exposure and Cooking Fuel on Insulin Resistance in the PURSE-HIS Cohort

摘要

Introduction: Evidence suggests that chronic exposure to ambient PM2.5 is associated with the prevalence and incidence of Diabetes Mellitus. This relationship has not been well explored in India, where there is an increased prevalence of diabetes and elevated exposures to PM2.5. Our study assessed associations between ambient and indoor PM2.5 exposure and cooking fuel type with insulin resistance as measured by the homeostasis model assessment of insulin resistance (HOMA-IR) method, in the Population study of Urban, Rural, Semi-urban Endovascular disease and Holistic Intervention Study (PURSE-HIS) in Tamil Nadu, India. Method: HOMA-IR was assessed in 8080 randomly selected participants. Estimates of ambient PM2.5 were derived using a combination of satellite retrieved aerosol optical depth and chemical transport modelling for 2010. For a subset of the cohort (n = 430), we measured indoor PM2.5, while for the rest of the sample we used cooking fuel as a proxy for indoor PM2.5. Multivariable regression models adjusted for age, BMI, sex, smoking, cooking fuel, socio-economic status. Models were stratified by sex given the difference in residential time-activity reported for females. Result: A 10 μg/m3 increase in ambient PM2.5 was significantly associated with a 0.8 mg/dl (95% CI: 0.5, 1.0) increase in HOMA-IR when adjusted for risk factors and cooking fuel. Cooking fuel type was not independently associated with HOMA-IR, but did have a significant interaction with ambient PM2.5, with higher effect on HOMA-IR in homes using solid fuels when compared to homes using LPG or a mix of fuels. A 10 μg/m3 increase in indoor PM2.5 had a non-significant association with HOMA-IR in female participants (0.05 mg/dl [95%CI: -0.09, 0.19]), but no association in males. Conclusion: Ambient PM2.5 was positively associated with HOMA-IR in both males and females. Indoor PM2.5 and cooking with solid fuel was associated with HOMA-IR in females only.