Cooking with biomass increases the risk of depression in pre-menopausal women in India.

Cooking with biomass fuel, a common practice in rural India, is associated with a high level of indoor air pollution (IAP). The aim of this study was to investigate whether IAP from biomass burning increases the risk of depression. For this cross-sectional study, we enrolled a group of 952 women (median age 37 years) who cooked regularly with biomass and a control group of 804 age-matched women who cooked with cleaner fuel (liquefied petroleum gas). Depression was assessed using the second edition of Beck's depression inventory (BDI-II). Platelet P-selectin expression was assessed by flow cytometry and platelet serotonin was measured by ELISA. Particulate matter having diameter of less than 10 and 2.5 μm (PM(10) and PM(2.5), respectively) in indoor air was measured by real-time aerosol monitor. Carbon monoxide (CO) in exhaled breath was measured by CO monitor. Compared with the control group, women who cooked with biomass had a higher prevalence of depression and depleted platelet serotonin, suggesting altered serotonergic activity in the brain. In addition, P-selectin expression on platelet surface was up-regulated implying platelet hyperactivity and consequent risk of cardiovascular disease. Biomass-using households had increased levels of PM(10) and PM(2.5), and biomass users had elevated levels of CO in expired air. Controlling potential confounders, cooking with biomass was found to be an independent and strong risk factor for depression. IAP from cooking with biomass is a risk for depression among rural women in their child-bearing age.