Dog Ownership and Mortality in England: A Pooled Analysis of Six Population-based Cohorts

Introduction: Dog ownership may be associated with reduced risk for cardiovascular disease. However, data are scant on the relationship between dog ownership and all-cause and cause-specific mortality risk. Methods: Data from six separate cohorts (1995-1997, 2001-2002, 2004) of the Health Survey for England were pooled and analyzed in 2017. Participants were 59,352 adults (mean age 46.5, SD = 17.9 years) who consented to be linked to the National Death Registry. Living in a household with a dog was reported at baseline. Outcomes included all-cause and cardiovascular disease mortality (determined using ICD-9 codes 390-459, ICD-10 codes I01-I99). Multilevel Weibull survival analysis was used to examine the associations between dog ownership and mortality, adjusted for various sociodemographic and lifestyle variables. Potential effect modifiers, including age, sex, education, living circumstances, longstanding illness, and prior diagnosis of cardiovascular disease, were also examined. Results: During 679,441 person-years of follow-up (mean 11.5, SD = 3.8 years), 8,169 participants died from all causes and 2,451 from cardiovascular disease. In the fully adjusted models, there was no statistically significant association between dog ownership and mortality outcomes (hazard ratio = 1.03, 95% CI = 0.98, 1.09, for all-cause mortality; and hazard ratio = 1.07, 95% CI = 0.96, 1.18, for cardiovascular disease mortality) and no significant effect modification. Conclusions: There is no evidence for an association between living in a household with a dog and all-cause or cardiovascular disease mortality in this large sample. These results should be interpreted in light of limitations in the measurement of dog ownership and its complexity in potential longterm health implications. Future studies should measure specific aspects of ownership, such as caring responsibilities and temporality. (C) 2017 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.