BACKGROUNDTo investigate the risk factors of lung cancer in female nonsmokers.

METHODSAn 1:1 matched case-control study was carried out in Shenyang, P.R.China. A questionnaire covering demographics, family history of cancer, previous disease history, living conditions, passive smoking history, occupational exposure, diet/nutritional preferences and cooking habits, sources of indoor pollution and so on was used to ask each subject. A total of 126 new cases diagnozed as primary lung cancer and 126 controls matched for age and sex were randomly selected from the female nonsmokers.

RESULTSAdenocarcinoma was the main type of female lung cancer, accounting for 62.7%. The higher number of deliveries was, the more risk of lung cancer was (OR=1.466, 95%CI=1.06-2.01). The lower the body mass index (BMI), the higher the risk of lung cancer (OR=2.082, 95%CI=1.2-3.60). With the increase of BMI, the risk of lung cancer decreased. Eating too much viscera (OR=1.891, 95%CI=1.45-2.46), maize and sorghum (OR=1.538, 95%CI= 1.22 -1.93) could increase the risk of lung cancer. Using petroleum gas as fuel (OR=1.741, 95%CI=1.29-2.34) and indoor coal burning (OR=1.785, 95%CI=1.33-2.38) were lung cancer's risk factors, too. The OR value of family cancer history of first-class relatives was 3.18 (95%CI=2.43-4.15).

CONCLUSIONSThe results suggest that low value of BMI, high number of child deliveries, eating too much viscera, maize and sorghum, indoor coal burning and using petroleum gas as fuel can increase the risk of lung cancer in female nonsmokers.