Indoor air pollution and risk of lung cancer among Chinese female non-smokers

Abstract

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.

Home kitchen ventilation, cooking fuels, and lung cancer risk in a prospective cohort of never smoking women in Shanghai, China

“…The association was strongest in women with both coal use and poor kitchen ventilation during both childhood and adulthood. Consistent with previous studies 24, 30–37 , poor indoor air quality was found to elevate lung cancer risk in our prospective cohort study. Conversely, we observed no elevated lung cancer risk associated with cooking oil use.…”

“…Previous studies on fuel use, ventilation, indoor air quality, and lung cancer risk were case-control studies 24, 30–37 . However, few studies were conducted in urban areas where rapid socioeconomic development led to substantial modernization in kitchen ventilation and fuel use 30, 31, 37 .…”

Global Cancer Incidence and Mortality Rates and Trends—An Update

“…12, 13). Exposure to indoor air pollution is thought to account for unexpectedly high rates of lung cancer among some populations with a low smoking prevalence, such as Chinese women (14).…”

Familial risk for lung cancer

“…Approximately, half of the world's population is at risk of developing respiratory diseases due to the use of unprocessed biomass fuel and coal for cooking and heating (10,11). A previous study conducted in China demonstrated that indoor air pollution has an important role in the development of lung cancer among Chinese women, particularly among never-smokers (9).…”

“…However, the exact genetic mechanisms influencing lung cancer susceptibility in female relatives in China are unknown (89). Indoor cooking is still practiced in some rural areas of China and in numerous other countries; this practice can be considered an important risk factor for lung cancer among women (11). The abovementioned studies suggest that lung cancer is likely to develop in genetically predisposed individuals.…”