Environmental risk factors for lung cancer in Iran: a case-control study.
BACKGROUND
Lung cancer remains the leading cause of cancer death in the world. In Iran, lung cancer is one of the five leading tumours and its incidence has been increasing steadily in both men and women. There is a paucity of data from Iran on risk factors for lung cancer. We evaluated environmental risk factors for lung cancer in a case-control study in five hospitals of Tehran.


METHODS
Between October 2002 and October 2005, 242 (178 male, 64 female) patients with histologically confirmed lung cancer and two controls for each patient (242 hospital controls and 242 visiting healthy controls) matched for age, sex and place of residence were interviewed using a structured questionnaire on potential risk factors for lung cancer, including environmental and occupational exposures. Associations between risk factors and lung cancer were assessed using conditional logistic regression.


RESULTS
Smokers were 66.5% of all cases (85.4% of men and 14.1% of women) and smoking was the strongest correlate of lung cancer in multivariate analysis [odds ratio (OR) 5.4, 95% confidence interval (CI) 3.2-8.9]. Occupational exposures to inorganic dusts (OR 4.2, 95% CI 2.8-6.7), chemical compounds (OR = 3.4, 95% CI 2.1-5.6) and heavy metals (OR 3.0, 95% CI 1.3-7.0) were also independent risk factors for lung cancer.


CONCLUSIONS
In our study, smoking was the principal risk factor for lung cancer. However, preventable exposures in the environment, including occupational settings, should not be ignored.
Hosseini
Mostafa
M
Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. mhossein110@yahoo.com
Naghan
Parisa Adimi
PA
Karimi
Shirin
S
SeyedAlinaghi
SeyedAhmad
S
Bahadori
Moslem
M
Khodadad
Kian
K
Mohammadi
Forouzan
F
Kaynama
Kaveh
K
Keynama
Kaveh
K
Masjedi
Mohammad Reza
MR
D000328:Adult; D000368:Aged; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008175:Lung Neoplasms / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects / Q000032:analysis; D017678:Sex Distribution; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology