Purpose To investigate indoor particulate matter (PM) level and various indoor air pollution exposure, and to examine their relationships with risk of lung cancer in an urban Chinese population, with a focus on non-smoking women. Methods We conducted a case-control study in Taiyuan, China, consisting of 399 lung cancer cases and 466 controls, of which 164 cases and 218 controls were female non-smokers. Indoor PM concentrations, including PM1, PM2.5, PM7, PM10 and TSP, were measured using a particle mass monitor. Unconditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals after adjusting for age, education, annual income and smoking. Results Among non-smoking women, lung cancer was strongly associated with multiple sources of indoor air pollution 10 years ago, including heavy exposure to ETS at work (aOR=3.65), high frequency of cooking (aOR=3.30), and solid fuel usage for cooking (aOR=4.08) and heating (aORcoal stove=2.00). Housing characteristics related to poor ventilation, including single-story, less window area, no separate kitchen, no ventilator and rarely having windows open, are associated with lung cancer. Indoor medium PM2.5 concentration was 68ug/m3, and PM10 was 230ug/m3. PM levels in winter are strongly correlated with solid fuel usage for cooking, heating and ventilators. PM1 levels in cases are more than 3-time higher than that in controls. Every 10 ug/m3 increase in PM1 is associated with 45% increased risk of lung cancer. Conclusions Indoor air pollution plays an important role in the development of lung cancer among non-smoking Chinese women.

Background and Purpose-Although a lower serum homocysteine concentration is associated with a reduced risk of stroke in epidemiologic studies, randomized, controlled trials have yielded mixed findings regarding the effect of therapeutic homocysteine lowering on stroke prevention. We performed a meta-analysis of randomized, controlled trials to assess the efficacy of folic acid supplementation in the prevention of stroke. Methods-Salient trials were identified by formal literature search. Relative risk (RR) with 95% CI was used as a measure of the association between folic acid supplementation and risk of stroke, after pooling data across trials in a fixed-effects model. Results-The search identified 13 randomized, controlled trials that had enrolled 39 005 participants for folic acid therapy to reduce homocysteine in which stroke was reported as an outcome measure. Across all trials, folic acid supplementation was associated with a trend toward mild benefit that did not reach statistical significance in reducing the risk of stroke (RRϭ0.93; 95% CI, 0.