Population attributable numbers and fractions of deaths due to smoking: a pooled analysis of 180,000 Japanese

Objective: Age- and sex-specific population attributable fraction (PAF) and premature deaths attributable to smoking were estimated from a pooled analysis of cohort studies in Japan.

Methods: A pooled analysis of individual participant data from 13 well-qualified cohort studies throughout Japan (a total of 183,251 Japanese aged 40-89, 69,502 men and 113,749 women; the baseline years between 1987 and 1995 with average 10 years of follow-up) was performed. Poison regression model was used to estimate age- and sex-specific hazard ratios, and their PAFs of all-cause deaths and number of annual premature deaths attributable to smoking were estimated.

Results: Overall PAF attributable to smoking was 24.6% in men and 6.0% in women. The estimated number of annual premature deaths due to smoking was 121,854 (men: 109,998; women: 11,856) in Japan. The age-specific PAF was largest in men aged 60-69 (47.7%) and in women aged 50-59 (12.2%). In the older group aged 70-79 and 80-89, PAF was 15.4% and 8.0% in men and 3.5% and 1.5% in women, respectively.

Conclusions: Age-specific PAFs attributable to smoking in Japanese men are much larger than that reported from other Asian countries.