Pulmonary function and risk of cancer: an inverse relationship?

Abstract

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The hypothesis as described by Cohen which states that pulmonary dysfunction is the underlying unifying factor which leads to the myriad health consequences (various types of cancers) of inhalation of toxicants was tested by compiling a retrospective cohort (n = 9534) composed of participants in nine population-based research and occupational studies conducted between 1977 and 1989. Smoking history, occupational exposures, health indicators (respiratory diseases and symptoms) and demographic information were obtained by questionnaire. Pulmonary function was assessed by spirometry using American Thoracic Society criteria. Identifiers for each individual were submitted to the Saskatchewan Cancer Agency population-based tumour registry in order to identify individuals who subsequently developed cancer before June 1997. After exclusion criteria were applied, 683 valid cases with cancer and 7668 control subjects remained. The four most prevalent tumours (excluding non-melanoma skin tumours) were all associated with cigarette smoking (prostate, bronchus and lung, colon, bladder). At baseline, those who subsequently developed neoplasms were less likely to have normal pulmonary function (76.1% vs 87.5%) and twice as likely to have obstructive disease (20.5% vs 8.3%) than those remaining tumour free supporting the hypothesis. Men who developed cancer of the bronchus/lung [OR (95% CI) 9.43 (5.56, 16.0)] were more likely than controls to have had obstructive disease at baseline. Less dramatic but significantly elevated rates were found for men with cancer of the prostate [4.12 (2.66, 6.83)] and, colon [2.66 (1.07, 6.60)] but not bladder [2.17 (0.73, 6.43)]. After statistical adjustment for age (4 groups), smoking history (nonsmoker, ever smoker), original study (nine groups) and sex (male, female), obstructive disease remained an independent predictor of cancer risk as were being an “ever” smoker, increasing age and participation in specific original studies (Town residents 77, Town residents 83, “Saskatchewan residents”, Potash workers).