Smoking rates among schizophrenia patients in Japan

According to the meta-analysis performed by de Leon and Diaz, the smoking rate was higher among schizophrenia patients than in the general population with the exception of the populations of Japan and Colombia. The purpose of this study was to reexamine the association between schizophrenia and smoking among Japanese schizophrenia patients using objective measures. The sample comprised 172 schizophrenia inpatients (mean age: 54 years; 55% male). Participants were asked by a psychiatrist whether they currently smoked, and their answers were confirmed by the Fagerstrom Test for Nicotine Dependence and a measurement of the carbon monoxide level in expired air. Data on 7496 Japanese people obtained from the national survey of health were used as the control group. Seventy schizophrenia patients (40.7%) were identified as smokers; the smoking rate was higher among men in their 50 s (66.7%) and among women in their 40s (54.6%). The smoking rate was 24.2% in the control group, and multiple logistic regression analysis showed that this percentage was significantly higher in the schizophrenia than in the control group (odds ratio: 2.17), adjusting for sex and age. The association between smoking rate and schizophrenia is consistent across countries, including Japan. (C) 2010 Published by Elsevier Ireland Ltd.