Smoking and Risk of Premature Death among Middle‐aged Japanese: Ten‐year Follow‐up of the Japan Public Health Center‐based Prospective Study on Cancer and Cardiovascular Diseases (JPHC Study) Cohort I

Abstract

To update the evidence on the association between smoking and mortality, we analyzed data from a population-based prospective study in Japan. In total, 19 950 men and 21 534 women aged 40-59 who reported their smoking history and had no serious disease at baseline survey were followed. During 1990-1999, 1014 men and 500 women died. Smokers were associated with an unhealthy lifestyle. Relative risks (RRs) for selected cause of death due to smoking were slightly attenuated by adjusting for possible confounding factors. Age-and area-adjusted RRs of male current smokers compared with never smokers were 1.66 (95% confidence intervals (CI Twenty-two percent of death from all causes, 25% of all cancer, and 17% of all circulatory system disease deaths, could be attributed to cigarette smoking in males, and 5%, 4%, and 11% in females, respectively. Cumulative dose as indicated by pack-years was clearly associated with cancer death. These findings provided information as to the quantitative risk for premature death due to smoking among middle-aged Japanese men and women, and showed that the elevated risk was not explained by the unhealthy lifestyle of smokers.Key words: Smoking -Mortality -Prospective study Cigarette smoking is an important and well-established risk factor of mortality and incidence of many cancers and cardiovascular disease.1-13) Prevalence of current cigarette smoking in Japan is higher than in the US and European countries, while relative risks (RRs) due to smoking and population attributable fraction (PAF) are lower in Japan. In the Cancer Prevention Study (CPS) II (1982-86), RRs due to smoking for all causes of death were reported 2.3 and 1.9 for men and women, respectively, and PAF% could be calculated 33% and 14% for men and women, respectively. 14) In Japan, RRs were reported to be 1.3 for either sex, while the PAF% was reported 18% and 4% for men and women, respectively, in a six-prefecture cohort study . 8)Because smokers are considered to have an unhealthy lifestyle, [15][16][17] smoking-related mortality has been considered to be affected by factors other than smoking itself, such as diet, alcohol, physical activity, and educational level. 13,[18][19][20][21][22] In the US, RRs of smoking for death were slightly altered by adjustment for other exposures in a recent study. 21) In Japan, Hirayama et al. conducted a sixprefecture cohort study , and established the risk of smoking, 8) although they calculated RRs while adjusting only for age. Since then, there have been no recent updates and no reports which analyzed RRs for death associated with tobacco smoking adjusted for other lifestyle-related factors from such a large cohort.Premature death represents a serious cost to society, and death at younger ages is one of the most important targets for future prevention of diseases. It is therefore of interest to study the etiological fraction of smoking in such premature death in the current Japanese population. In this study, we update the potential health hazards of cigarette smoking adjusted for ...

Smoking and Risk of All-cause Mortality: The Jichi Medical School (JMS) Cohort Study

“…The six-prefecture cohort study 29 The Miyagi Cohort Study 31 The Japan Public Health Center-based Prospective Study 30 The Jichi Medical School Cohort Study 33 were higher than those of the present study. Other reports showed that the RRs of current smokers were higher than our results.…”

“…30 The Miyagi Cohort Study (MCS) followed up 36,052 subjects aged 40-64 years during an 11-year period, 31 and the multivariate-adjusted RRs were 1.71 in males and 1.44 in females. The results of these two studies for males approximated ours and a comparison was reasonable because their research was similar to ours in terms of subjects, observation time, and period of observation.…”

Cigarette Smoking and Mortality in Japan: The Miyagi Cohort Study

“…[9][10][11] All of them demonstrated that smoking habit was harmful. However, there has been only one study in Japan that analyzed the RR for all-cause mortality associated with cigarette smoking with extensive adjustment for possible confounders.…”

“…[9][10][11] Since smoking habit often accompanies with unhealthy lifestyle, appropriate control for confounding factors is necessary to estimate the hazard of cigarette smoking.12-14 However, there have been only one Japanese study that analyzed the relative risk (RR) for all-cause mortality associated with cigarette smoking adjusted for possible confounders.9 Therefore, we conducted a prospective study among Japanese men and women to examine the association between cigarette smoking and all-cause mortality. The objective of this study was (1) to clarify the association between smoking habit and the other risk factors, (2) to investigate the association between smoking habit and all-cause mortality, (3) to examine the proportion of premature death from all causes attributable to cigarette smoking, and (4) to examine the effect of duration of smoking cessation on all-cause mortality.…”

“…[9][10][11] Since smoking habit often accompanies with unhealthy lifestyle, appropriate control for confounding factors is necessary to estimate the hazard of cigarette smoking.…”