Analyzing excess mortality from cancer among individuals with mental illness

Abstract

BACKGROUND: The objective was to compare patterns of site-specific cancer mortality in a population of individuals with and without mental illness. METHODS: This was a cross-sectional, population-based study using a linked data set comprised of death certificate data for the state of Ohio for the years 2004-2007 and data from the publicly funded mental health system in Ohio. Decedents with mental illness were those identified concomitantly in both data sets. We used age-adjusted standardized mortality ratios (SMRs) in race- and sex-specific person-year strata to estimate excess deaths for each of the anatomic cancer sites. RESULTS: Overall, there was excess mortality from cancer associated with having mental illness in all the race/sex strata: SMR, 2.16 (95% CI, 1.85-2.50) for black men; 2.63 (2.31-2.98) for black women; 3.89 (3.61-4.19) for nonblack men; and 3.34 (3.13-3.57) for nonblack women. In all the race/sex strata except for black women, the highest SMR was observed for laryngeal cancer, 3.94 (1.45-8.75) in black men and 6.51 (3.86-10.35) and 6.87 (3.01-13.60) in nonblack men and women, respectively. The next highest SMRs were noted for hepatobiliary cancer and cancer of the urinary tract in all race/sex strata, except for black men. CONCLUSIONS: Compared with the general population in Ohio, individuals with mental illness experienced excess mortality from most cancers, possibly explained by a higher prevalence of smoking, substance abuse, and chronic hepatitis B or C infections in individuals with mental illness. Excess mortality could also reflect late-stage diagnosis and receipt of inadequate treatment.