Risk factors for primary lung cancer among never smokers by gender in a matched case-control study.
OBJECTIVE
Lung cancers that occur in never smokers differ from those that occur in smokers. We performed an analysis of potential epidemiological risk factors for lung cancer among never smokers.


METHODS
In this hospital-based matched case-control study, all 1,540 matched case-control pairs were Han Chinese in Taiwan. The data on demographic characteristics, smoking habit, exposure to environmental tobacco smoke, medical history of lung diseases, family history of lung cancer, and female characteristics were collected from a structured questionnaire. A multiple conditional logistic regression was used to estimate odds ratios and 95 % confidence intervals after adjusting for possible confounders.


RESULTS
Overall, several epidemiological factors of lung cancer in never smokers were different between males and females. For the female population, subjects who were exposed to environmental tobacco smoke (OR = 1.39, 95 % CI = 1.17-1.67) with a history of pulmonary tuberculosis and with family history of lung cancer in first-degree relatives (OR = 2.44, 95 % CI = 1.79-3.32) had higher risk of lung cancer, while subjects with a history of hormone replacement therapy and using fume extractors for those who cooked were protective. For the male population, only subjects with family history of lung cancer in first-degree relatives (OR = 2.77, 95 % CI = 1.53-5.01) were significantly associated with risk of lung cancer.


CONCLUSIONS
This study provides insights about the epidemiological factors of lung cancer in never smokers, adding to existing evidence that family history of lung cancer and environmental tobacco smoke may moderate lung cancer risk.
Institute of Population Health Sciences, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County 350, Taiwan.
Yen-Li
YL
Lo
Chin-Fu
CF
Hsiao
Gee-Chen
GC
Chang
Ying-Huang
YH
Tsai
Ming-Shyan
MS
Huang
Wu-Chou
WC
Su
Yuh-Min
YM
Chen
Che-Wei
CW
Hsin
Chin-Hao
CH
Chang
Pan-Chyr
PC
Yang
Chien-Jen
CJ
Chen
Chao A
CA
Hsiung
D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology*; D013624:Taiwan / Q000453:epidemiology; D014028:Tobacco Smoke Pollution / Q000009:adverse effects / Q000706:statistics & numerical data*
D014028:Tobacco Smoke Pollution