Cigarette smoking and mortality risk in people with schizophrenia

Abstract

This study examined effects of cigarette smoking on mortality risk in 1213 persons aged 19-69 years with schizophrenia-related psychotic disorders admitted to State of Maryland Hospitals between 1994 and 2000. Inpatient medical records from 7 hospitals were reviewed to obtain demographic information, diagnosis, medication use, as well as smoking and other substance use. Social Security Death Index data were used to identify deaths in the study group between 1994 and 2004. Death records were reviewed to obtain manner of death and underlying disorders. Of the 1213, 55% were smokers and 71% abused substances. There was an age × smoking interaction (χ(2) = 14.6, df = 1, P = .0001) for mortality, with estimated hazard ratios (HRs) for smokers vs nonsmokers of 2.1 among 35- to 54-year olds and HR of 0.7 among those aged 55-69 years. Five- and 10-year mortality rates for smokers aged 35-54 years were 7.0% and 14.2%, compared with 3.3% and 10.0% for nonsmokers, respectively (χ(2) = 5.53, df = 1, P = .019). Cardiac causes were identified in 43% of deaths in smokers but only 19% of deaths in nonsmokers (P < .006). For those aged 35-54 years, the odds of cardiac related death was increased by 12 fold in smokers relative to nonsmokers (HR = 12.4, χ(2) = 12.0, df = 1, P = .0005). Among people aged 35-54 years, those smoking greater than one pack daily have a significantly increased total mortality risk (HR = 2.7) vs nonsmokers. Cigarette smoking, particularly in people aged 35-54 years, contributes to an increased risk of death. Greater smoking severity significantly increases this risk. Smoking cessation in people with schizophrenia deserves significant attention.

Fig. 1.

Time to Death in Smokers Vs Nonsmokers by Age Group. Kaplan-Meier Estimates of Cumulative Probability of All-Cause Death by Years of Follow-up, Age, and Smoking Status. Tests of mortality difference from the Cox proportional hazards model—smoking (age < 35 y): hazard ratio (95% confidence interval [CI]) = 1.24 (0.57–2.70), P = .590; smoking (age 35–54 y): hazard ratio (95% CI) = 2.06 (1.37–3.10), P = .0006; smoking (age ≥55 y): hazard ratio (95% CI) = 0.65 (0.42–0.99), P = .047; difference in hazard ratio age <35 y vs age 35–54 y: P =.258; difference in hazard ratio age 35–54 y vs age≥55 y: P = .0001.