Estimating the incidence of lung cancer attributable to occupational exposure in Iran

ObjectiveTo estimate the impact of intensity of both smoking and occupational exposure to asbestos on the risk of lung cancer throughout the whole exposure history.MethodsData on 2026 male cases and 2610 male controls came from the French ICARE (Investigation of occupational and environmental causes of respiratory cancers) population-based, case–control study. Lifetime smoking history and occupational history were collected from standardised questionnaires and face-to-face interviews. Occupational exposure to asbestos was assessed using a job exposure matrix. The effects of annual average daily intensity of smoking (reported average number of cigarettes smoked per day) and asbestos exposure (estimated average daily air concentration of asbestos fibres at work) were estimated using a flexible weighted cumulative index of exposure in logistic regression models.ResultsIntensity of smoking in the 10 years preceding diagnosis had a much stronger association with the risk of lung cancer than more distant intensity. By contrast, intensity of asbestos exposure that occurred more than 40 years before diagnosis had a stronger association with the risk of lung cancer than more recent intensity, even if intensity in the 10 years preceding diagnosis also had a significant effect.ConclusionOur results illustrate the dynamic of the effect of intensity of both smoking and occupational exposure to asbestos on the risk of lung cancer. They confirm that the timing of exposure plays an important role, and suggest that standard analytical methods assuming equal weights of intensity over the whole exposure history may be questionable.

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Smoking and Lung Cancer in Bangladesh

TAJ Journal of Teachers Association ◽

10.3329/taj.v22i2.37725 ◽

2009 ◽

Vol 22 (2) ◽

pp. 207-211

Author(s):

Dayem Uddin ◽

I Mahmood ◽

S Kundu

Keyword(s):

Lung Cancer ◽

Occupational Exposure ◽

Cancer Risk ◽

Lung Cancer Risk ◽

Baseline Risk ◽

Risk Area ◽

College Hospital ◽

North West ◽

Medical College ◽

Using Data

We studied the relationship between smoking and lung cancer risk in North-West and Southern region of our country with a very high baseline risk of lung cancer in male sex using data from a case-control study of lung cancer conducted between May, 1999 and May, 2004 at Rajshahi Medical College Hospital. Cases were 218 patients with incident, histologically confirmed lung cancer and controls were 436 patients admitted to the same hospital with non-neoplastic and non-lung diseases. Compared with never-smokers, the multivariate odds ratio (OR) for current smokers was 3.47[95%confidence interval (Cl) 2.31-5.20), and for ex-smokers 1.53 (95% Cl 0.81-2.87). Lung cancer risk increased by 20% (95% Cl 14% to 28%) for an increment of five cigarettes per day. The OR for smokers reporting occupational exposure to selected known or likely lung carcinogens was 7.22, compared with non-smokers without occupational exposure. This study further confirms that cigarette smoking is a strong determinant of lung cancer also in this high risk area of North-West and Southern area of our Bangladesh.TAJ 2009; 22(1): 207-211

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