Pet ownership and the risk of dying from lung cancer, findings from an 18 year follow-up of a US national cohort

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Environmental Research




Purpose In contrast to the popularity of pets, research on the health effects of living with pets, particularly, on the risk of cancer, is minimal and inconclusive. We longitudinally examined relationships between pet ownership and the risk of dying from lung cancer. Methods We analyzed nationally representative data of 13,725 adults aged ≥ 19 who answered the question about pet ownership in the Third National Health and Nutrition Examination Survey, 1988–1994, as the baseline survey. Vital status was followed through December 31st, 2010. Results About 43% of the study population owned pets, with 20.4% having cats and 4.6% having birds. A total of 213 lung cancer deaths were recorded by the end of 183,094 unweighted person-years of follow-up with a lung-cancer specific death rate of 1.00 per 1000 person-years. After adjustment for cigarette smoking, alcohol drinking, physical activity, body mass index, history of atopic conditions, and serum cotinine, owning a pet (any) was associated with a doubled mortality rate among women for lung cancer [hazard ratio (HR)= 2.31 (1.41–3.79)] over non-owners. This association was largely attributed to having a cat or a bird. The HR was 2.85 (1.62–5.01) for cats, and 2.67 (0.68−10.5) for birds. The HR for dogs was 1.01 (0.57–1.77). No significant patterns of association were observed among men either for any pets or for a subtype of pet. Conclusions Living with a pet, especially, a cat or a bird, was significantly associated with elevated hazard of dying from lung cancer among women. The detrimental effect that pets conferred was not explained by confounding from cigarette smoking or atopic conditions.