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

Projecting the impact of implementation of WHO MPOWER measures on smoking prevalence and mortality in Japan

OBJECTIVE

This study aimed to quantify the long-term impact of implementing the WHO Framework Convention on Tobacco Control (FCTC) compliant tobacco control measures, MPOWER, on smoking prevalence and mortality in men and women aged ≥20 years in Japan.

DESIGN

A Stock-and-Flow simulation model was used to project smoking prevalence and mortality from 2018 to 2050 under eight different scenarios: (1) maintaining the 2018 status quo, (2) implementation of smoke-free policies, (3) tobacco use cessation programmes, (4-5) health warning about the dangers of tobacco (labels, mass media), (6) enforcement of tobacco advertising bans or (7) tobacco taxation at the highest recommended level and (8) all these interventions combined.

RESULTS

Under the status quo, the smoking prevalence in Japan will decrease from 29.6% to 15.5% in men and 8.3% to 4.7% in women by 2050. Full implementation of MPOWER will accelerate this trend, dropping the prevalence to 10.6% in men and 3.2% in women, and save nearly a quarter million deaths by 2050. This reduction implies that Japan will only attain the current national target of 12% overall smoking prevalence in 2033, 8 years earlier than it would with the status quo (in 2041), a significant delay from the national government's 2022 deadline.

CONCLUSIONS

To bring forward the elimination of tobacco smoking and substantially reduce smoking-related deaths, the government of Japan should fulfil its commitment to the FCTC and adopt stringent tobacco control measures delineated by MPOWER and beyond.

Construct validity of the Questionnaire for Older Senior Citizens based on a confirmatory factor analysis: A study during the period of self-restraint to prevent the spread of coronavirus disease 2019

Aim

This study aims to clarify the construct and criterion‐related validity of the Questionnaire for Older Senior Citizens (QO) during the COVID‐19 pandemic.

Methods

This cross‐sectional study was conducted in Japan between November 11, 2020 and January 10, 2021. Of the 1645 (63.5%) older adults who responded, data from 900 participants were analyzed. First, we conducted an exploratory factor analysis (EFA) among older‐older adults (aged ≥75 years) and extracted the factors. Next, we conducted a confirmatory factor analysis (CFA) using structural equation modeling. We also conducted this analysis among younger‐older adults (aged ≥65 and <75 years) using the same model. Moreover, we compared each item of the QO with frailty status.

Results

Results of the EFA revealed six factors: social conditions and lifestyle, subjective conditions, cognitive functions, physical activity, oral functions, and physical functions. The results of the CFA were as follows: comparative fit index (CFI) = 0.971, adjusted goodness of fit index (AGFI) = 0.978, root mean square error of approximation (RMSEA) = 0.018, and standardized root mean square residual (SRMR) = 0.030. The results among the younger‐older adults were as follows: CFI = 0.880, AGFI = 0.940, RMSEA = 0.037, and SRMR = 0.048. Many QO items were significantly associated with frailty (P < 0.05).

Conclusions

Among the older‐older adults group, the model used for the QO has sufficient suitability and construct validity; among the younger‐older adults group, there also is sufficient questionnaire suitability. Moreover, the QO has criterion related validity with frailty. Geriatr Gerontol Int 2021; 21: 1018–1025.

Exposures to Potentially Psychologically Traumatic Events Among Nurses in Canada

BACKGROUND

Nurses are regularly exposed to diverse potentially psychologically traumatic events (PPTEs) as a function of their work. Cumulative exposure to PPTEs can lead to clinically significant symptoms of mental disorders.

PURPOSE

We designed the current study to investigate the prevalence of different PPTEs among Canadian nurses and estimate the associations between diverse exposures and several mental disorders.

METHODS

Canadian nurses (i.e., registered nurses, registered psychiatric nurses, licensed practical nurses, nurse practitioners) completed an online, self-reported survey. In total, 4067 participants (94.8% women) completed all relevant survey measures.

RESULTS

Nurses reported exposures to several PPTE categories including severe human suffering, life threatening illness or injury, and physical assault, often 11 or more times. There were significant (p<.05) associations between diverse traumatic events and all mental disorders (i.e., Posttraumatic Stress Disorder, Major Depressive Disorder, Generalized Anxiety Disorder, Panic Disorder) except Alcohol Use Disorder.

CONCLUSIONS

The current findings suggest that Canadian nurses are substantially exposed to traumatic events, which vary by several sociodemographic categories. PPTE exposures were significantly associated with mental disorders; that is, if PPTEs were eliminated among Canadian nurses in the sample, symptoms would be reduced between 42.0% and 58.0%.

Heated Tobacco Products Have Reached Younger or More Affluent People in Japan

Background

The trend of the diffusion of heated tobacco products (HTPs) is a great concern because HTPs have become available worldwide. This study examined the sociodemographic characteristics of HTPs users in Japan, where HTPs were first launched.

Methods

This cross-sectional study used data from an online survey conducted in 2017. A total of 4,926 participants, aged 20–69 years, were included. The dependent variable was the type of tobacco products used. The independent variables were age and equivalent income. Two analyses estimated the odds ratios (ORs) for 1) being smokers compared to “non-smokers,” and 2) being “HTP smokers” compared to “only combustible cigarette smokers.” Analyses were stratified by sex. Educational attainment and occupation were also used in the sensitivity analyses.

Results

The percentages of “non-smokers,” “only combustible cigarette smokers,” and “HTP smokers” were 82.8%, 14.2%, and 3.0%, respectively. When compared to the oldest participants (aged 60–69), the youngest participants (aged 20–29) tended to be “HTP smokers” (OR 7.90; 95% confidence interval [CI], 3.09–20.22 for men and OR 9.28; 95% CI, 2.14–40.28 for women). Compared to participants with the lowest incomes (<2 million), those with the highest incomes (≥4 million) tended to use HTPs (OR 2.93; 95% CI, 1.56–5.49 in men and OR 1.82; 95% CI, 0.73–4.54 in women). These trends were consistent when analyses included only smokers. There were consistent results in other SES measurements, including educational attainment and occupation.

Conclusions

Younger or more affluent people tended to use HTPs, although smoking rates among these populations were generally lower. New tobacco control efforts are required.

Effectiveness of Text-Only Cigarette Health Warnings in Japan: Findings from the 2018 International Tobacco Control (ITC) Japan Survey

Health warnings are an effective strategy for communicating the health harms of smoking, encouraging quitting, and preventing smoking initiation. This study examines the effectiveness of existing text-only health warnings, identifies key predictors of warning effectiveness, and assesses support for pictorial warnings in Japan. Data are from the 2018 International Tobacco Control (ITC) Japan Survey, a cohort survey of adult cigarette smokers (n = 3306), dual users of cigarettes and heated tobacco products (n = 555), and non-cigarette smokers (n = 823). Weighted multivariable logistic regression models were used to assess predictors of warning effectiveness and support for pictorial warnings. Overall, 15.6% of respondents noticed warnings, and 7.9% read or looked closely at warnings. Overall, 10.3% of smokers and dual users said the warnings stopped them from having a cigarette, and 7.2% avoided warnings. Overall, 27.5% of respondents said the warnings made them think about health risks of smoking, but only 2.7% of smokers and dual users said the warnings made them more likely to quit. Overall, 57.6% of respondents supported pictorial warnings. The weak effectiveness of Japan's text-only warnings is consistent with that in other countries with similar warnings. There is majority support for pictorial warnings in Japan, although the level of support is lower than in other countries.

Changes in Smoking Status and Mortality From All Causes and Lung Cancer: A Longitudinal Analysis of a Population-based Study in Japan

BACKGROUND

To update the findings of relative risk associated with smoking for all-cause mortality and that for lung cancer by considering longitudinal changes in smoking status during follow-up.

METHODS

Data from the JPHC study of 98,747 middle-aged Japanese adults, which started in 1990-1993, were analyzed. The information on smoking status was obtained from three questionnaire surveys (baseline, the 5th year, and the 10th year after the start of follow-up). A Poisson regression model was used to investigate the impact of smoking on mortality from all causes and lung cancer using two approaches. Model 1 used information only from baseline, while model 2 used the updated smoking status from all three surveys.

RESULTS

During the 15-year follow-up, 10,702 all-cause deaths (including 870 lung cancer cases) were identified. We compared the results obtained from two models. The relative risks associated with former smokers versus never smokers were 1.42 (95% confidence interval [CI], 1.31-1.54) among men and 1.46 (95% CI, 1.23-1.73) among women for all-cause mortality and 2.98 (95% CI, 2.09-4.24) among men and 1.83 (95% CI, 0.92-3.64) among women for lung cancer mortality, as determined using model 2. All of these were higher than the relative risks obtained from model 1. In addition, former smokers who had quit smoking due to disease during follow-up had a higher mortality risk than continuous smokers did in this study.

CONCLUSIONS

The relative risks of all-cause mortality and mortality due to lung cancer among former smokers be higher than previously documented based on updated smoking status data from repeated surveys.

Association Between Body Mass Index and All-Cause Death in Japanese Population: Pooled Individual Participant Data Analysis of 13 Cohort Studies

BACKGROUND

We sought to investigate the optimal values of BMI for the lowest risk of all-cause death and whether the optimal BMI differs according to smoking status in large-scale pooled analysis of 13 Japanese cohorts.

METHODS

Data from 179,987 participants of 13 well-qualified cohort studies conducted throughout Japan were used for our analysis. A cohort-stratified Cox proportional hazard model was used. P values for interactions were calculated based on the cross product of BMI and age, sex, or smoking status.

RESULTS

In the entire study population, all-cause mortality risk was lowest when the BMI was 22.0-24.9 kg/m². This was also the case for selected healthy participants (never smoked, baseline total cholesterol level ≥4.1 mmol/L; the first 5 years of follow-up data were excluded). No effect modification of age, sex, or smoking status was observed. Regardless of their BMI, never smokers always had a lower all-cause mortality risk than did current smokers even with an ideal BMI in terms of mortality risk.

CONCLUSION

A BMI of 22-24.9 kg/m² correlated with the lowest risk of mortality, regardless of whether all participants or selected healthy participants were analyzed. The fact that smoking was more strongly associated with mortality than obesity emphasizes the urgency for effective anti-smoking programs.

Social and Behavioural Determinants of the Difference in Survival among Older Adults in Japan and England

BACKGROUND

A rapidly ageing population presents major challenges to health and social care services. Cross-country comparative studies on survival among older adults are limited. In addition, Japan, the country with the longest life expectancy, is rarely included in these cross-country comparisons.

OBJECTIVE

We examined the relative contributions of social and behavioural factors on the differences in survival among older people in Japan and England.

METHODS

We used data from the Japan Gerontological Evaluation Study (JAGES; n = 13,176) and the English Longitudinal Study of Ageing (ELSA; n = 5,551) to analyse all-cause mortality up to 9.4 years from the baseline. Applying Laplace regression models, the 15th survival percentile difference was estimated.

RESULTS

During the follow-up, 31.3% of women and 38.6% of men in the ELSA died, whereas 19.3% of women and 31.3% of men in the JAGES died. After adjusting for age and baseline health status, JAGES participants had longer survival than ELSA participants by 318.8 days for women and by 131.6 days for men. Family-based social relationships contributed to 105.4 days longer survival in JAGES than ELSA men. Fewer friendship-based social relationships shortened the JAGES men's survival by 45.4 days compared to ELSA men. Currently not being a smoker contributed to longer survival for JAGES women (197.7 days) and ELSA men (46.6 days), and having lower BMI reduced the survival of JAGES participants by 129.0 days for women and by 212.2 days for men.

CONCLUSION

Compared to participants in England, Japanese older people lived longer mainly because of non-smoking for women and family-based social relationships for men. In contrast, a lower rate of underweight, men's better friendship-based social relationships, and a lower smoking rate contributed to survival among participants in England.

Smoking cessation and subsequent risk of cancer: A pooled analysis of eight population-based cohort studies in Japan

BACKGROUND

Although East Asia is one of the largest tobacco-epidemic regions in the world, only a few prospective studies from Asia have investigated the impact of smoking and cessation of smoking on cancer. We aimed to assess the effect of cessation of smoking on the risk of cancer using eight population-based cohort studies in Japan.

METHODS

We analyzed pooled data from eight population-based prospective cohort studies in Japan with more than 320,000 participants to assess the effect of smoking cessation on the risk of total cancers and smoking-related cancers.

RESULTS

After adjustment for potential confounders, cancer risks in men with >21years of smoking cessation before baseline were found to decrease to the same level as never smokers for total cancer (never smokers: reference; former smokers with ≥21 years since smoking cessation: HR, 1.01; 95%CI: 0.91, 1.11). Even men who are heavy smokers (more than 20 pack-years) reported a reduced risk of total cancer (never smokers: reference; former smokers with ≥21 years since smoking cessation: HR, 1.06; 95%CI: 0.92, 1.23). In women, the risk of total cancer did not differ from that of never smokers after 11 years of smoking cessation before baseline (never smokers: reference; former smokers with ≥11 years since smoking cessation: HR, 0.96; 95%CI: 0.74, 1.23).

CONCLUSIONS

Our study suggests that longer duration of smoking cessation may attenuate the risk of cancer in both men and women, and that even heavy smokers (more than 20 pack-years) were found to benefit from quitting smoking.

Age-specific impact of diabetes mellitus on the risk of cardiovascular mortality: An overview from the evidence for Cardiovascular Prevention from Observational Cohorts in the Japan Research Group (EPOCH-JAPAN)

Background

Diabetes mellitus is a strong risk factor for cardiovascular disease. However, the age-specific association of diabetes with cardiovascular risk, especially in the elderly, remains unclear in non-Western populations.

Methods

A pooled analysis was conducted using 8 cohort studies (mean follow-up period, 10.3 years) in Japan, combining the data from 38,854 individual participants without history of cardiovascular disease. In all, 1867 of the participants had diabetes, defined based on the 1998 World Health Organization criteria. The association between diabetes and the risk of death from cardiovascular disease, coronary heart disease (CHD), and stroke was estimated using a stratified Cox model, accounting for variability of baseline hazard functions among cohorts.

Results

During the follow-up, 1376 subjects died of cardiovascular disease (including 268 of coronary heart disease and 621 of stroke). Diabetes was associated with an increased risk of cardiovascular death after multivariable adjustment (hazard ratio [HR] 1.62; 95% confidence interval [CI], 1.35–1.94). Similarly, diabetes was a risk factor for CHD (HR 2.13; 95% CI, 1.47–3.09) and stroke (HR 1.40; 95% CI, 1.05–1.85). In the age-stratified analysis of the risk of cardiovascular death, the relative effects of diabetes were consistent across age groups (p for heterogeneity = 0.18), whereas the excess absolute risks of diabetes were greater in participants in their 70s and 80s than in younger subjects.

Conclusions

The management of diabetes is important to reduce the risk of death from cardiovascular disease, not only in midlife but also in late life, in the Japanese population.

•

We conducted meta-analysis of individual data from 8 Japanese cohorts (n = 38,854).

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Diabetes raised cardiovascular mortality in Japan.

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Impact of diabetes on cardiovascular death was similar across 10-year age groups.

Serum Uric Acid and Mortality Form Cardiovascular Disease: EPOCH-JAPAN Study

AIM

To investigate the relationship between serum uric acid levels and cardiovascular disease in Asians.

METHODS

We examined the above relationship using the data of Evidence for Cardiovascular Prevention from Observational Cohorts in Japan (EPOCH-JAPAN Study). The data of 36,313 subjects (15,628 men and 20,685 women aged 35-89 years without histories of stroke, coronary heart disease, or cancer at baseline) were used for the analyses. Sex-specific hazard ratios (HRs) of mortality from cardiovascular disease were estimated according to the quintiles of serum uric acid using Cox hazard models stratified by cohorts.

RESULTS

During 441,771 person-years of follow-up, we documented 1,288 cardiovascular deaths. A J- or U-shaped relationship between serum uric acid level and cardiovascular disease mortality was observed. Compared with the lowest quintile of serum uric acid levels, the highest quintile was associated with an increased cardiovascular disease mortality in men [HR: 1.28; 95% confidence interval (CI): 1.01-1.63] and women (HR: 1.51; 95% CI: 1.14-1.99). However, there was no significant association with mortality from stroke, coronary heart disease or heart failure in both men and women.

CONCLUSION

This large pooled analysis in Japan suggested a J- or U-shaped relationship between serum uric acid levels and cardiovascular mortality. The highest quintile of serum uric acid levels was associated with increased cardiovascular disease mortality in both Japanese men and women.

Serum γ-glutamyltransferase and Mortality due to Cardiovascular Disease in Japanese Men and Women

AIM

Whether the association between serum γ-glutamyltransferase (γ-GTP) levels and total cardiovascular disease (CVD) mortality is independent of alcohol drinking in East Asian populations is not well known. We conducted a pooled analysis of Japanese men and women that enabled an analysis restricted to never-drinkers.

METHODS

A total of 15,987 men and 25,053 women aged 40-79 years, pooled from seven cohort studies throughout Japan, were followed-up to examine sex-specific relationship between serum γ-GTP levels and total CVD mortality. Cox regression model was used that was adjusted for age, smoking status, body mass index, and systolic blood pressure and serum triglyceride, total cholesterol, aspartate aminotransferase, and alanine aminotransferase levels.

RESULTS

During an average follow-up of 8.7 years, we documented 361 and 340 deaths from total CVD, 146 and 168 from stroke, and 101 and 53 from coronary heart disease (CHD) for men and women, respectively. Among the never-drinkers, hazard ratios (HRs) for mortality for one standard deviation of log-γ-GTP for men were 1.89 (1.00-3.58) for stroke, 1.04 (0.57-1.90) for CHD, and 1.43 (1.04-1.96) for total CVD. For women, HRs were 1.28 (1.06-1.54), 1.81 (1.34-2.44), and 1.30 (1.14-1.49), respectively.

CONCLUSION

γ-GTP may be a risk factor for total CVD mortality independent of alcohol drinking status in Japanese men and women.

Comparison of Prevalence- and Smoking Impact Ratio-Based Methods of Estimating Smoking-Attributable Fractions of Deaths

Background

Smoking is a major modifiable risk factor for premature mortality. Estimating the smoking-attributable burden is important for public health policy. Typically, prevalence- or smoking impact ratio (SIR)-based methods are used to derive estimates, but there is controversy over which method is more appropriate for country-specific estimates. We compared smoking-attributable fractions (SAFs) of deaths estimated by these two methods.

Methods

To estimate SAFs in 2012, we used several different prevalence-based approaches using no lag and 10- and 20-year lags. For the SIR-based method, we obtained lung cancer mortality rates from the Korean Cancer Prevention Study (KCPS) and from the United States-based Cancer Prevention Study-II (CPS-II). The relative risks for the diseases associated with smoking were also obtained from these cohort studies.

Results

For males, SAFs obtained using KCPS-derived SIRs were similar to those obtained using prevalence-based methods. For females, SAFs obtained using KCPS-derived SIRs were markedly greater than all prevalence-based SAFs. Differences in prevalence-based SAFs by time-lag period were minimal among males, but SAFs obtained using longer-lagged prevalence periods were significantly larger among females. SAFs obtained using CPS-II-based SIRs were lower than KCPS-based SAFs by >15 percentage points for most diseases, with the exceptions of lung cancer and chronic obstructive pulmonary disease.

Conclusions

SAFs obtained using prevalence- and SIR-based methods were similar for males. However, neither prevalence-based nor SIR-based methods resulted in precise SAFs among females. The characteristics of the study population should be carefully considered when choosing a method to estimate SAF.

Calibration between the Estimated Probability of the Risk Assessment Chart of Japan Atherosclerosis Society and Actual Mortality Using External Population: Evidence for Cardiovascular Prevention from Observational Cohorts in Japan (EPOCH-JAPAN)

AIM

In Japan Atherosclerosis Society guidelines for the prevention of atherosclerotic cardiovascular diseases 2012 (JAS2012), NIPPON DATA80 risk assessment chart (ND80RAC) was adopted to estimate the 10-year probability of coronary artery disease (CAD) mortality. However, there was no comparison between the estimated mortality calculated by ND80RAC and actual mortality in external populations. Accordingly, we used the large pooled database of cohorts in Japan, EPOCH-JAPAN, as an external population.

METHODS

The participants of EPOCH-JAPAN without a history of cardiovascular disease (15,091 men and 18,589 women aged 40-74 years) were analyzed based on sex. The probability of a 10-year risk of CAD/stroke mortality was estimated by ND80RAC. The participants were divided into both decile of their estimated mortality and three categories according to JAS2012. The calibration between the mean estimated mortality and the actual mortality was performed by the Hosmer and Lemeshow (H-L) test.

RESULTS

In both sexes, the estimated CAD mortality was higher than the actual mortality, particularly in higher deciles of estimated mortality, and the estimated stroke mortality was almost concordant with the actual mortality in low/moderate deciles of estimated mortality. As for the categories according to JAS2012, the estimated CAD mortality was higher than the actual mortality in both sexes; actual mortality in Category III was lower than that in Category II in women. However, it increased in the ascending order of category when we excluded the presence of diabetes from Category III.

CONCLUSIONS

The estimated CAD mortality by ND80RAC tended to be higher than the actual mortality in the population in which the baseline survey was more recently performed.

[The need for tobacco control in Japan based on Articles 9 and 10 of the World Health Organization Framework Convention on Tobacco Control (WHO FCTC), regulation of the contents of tobacco products, and regulation of tobacco product disclosures]

In Japan, ultralow-nicotine cigarette brands with ventilation holes on the cigarette filters have been widely marketed to smokers. The use of these cigarette brands leads to compensation smoking. Menthol cigarette brands that have a cooling and numbing effect are also sold. In 2013, smokeless tobacco products similar to the Swedish snus, which is banned for sale in the European Union except in Sweden, were released in Japanese markets. These tobacco products have "toxicity," have a "ventilation filter," are "attractive," and promote "dependence." Tobacco smoke and smokeless tobacco are classified into "Group 1: Carcinogenic to humans" by the International Agency for Research on Cancer (IARC). The purpose of Articles 9 and 10 of the World Health Organization Framework Convention on Tobacco Control (WHO FCTC) is to regulate the contents of tobacco products as well as to regulate tobacco product disclosures. The implementation of some other articles has gradually advanced in Japan. However, that of Articles 9 and 10 is late. Japanese governmental authorities are being urged to immediately implement Articles 9 and 10.

Burden of total and cause-specific mortality related to tobacco smoking among adults aged ≥ 45 years in Asia: a pooled analysis of 21 cohorts

BACKGROUND

Tobacco smoking is a major risk factor for many diseases. We sought to quantify the burden of tobacco-smoking-related deaths in Asia, in parts of which men's smoking prevalence is among the world's highest.

METHODS AND FINDINGS

We performed pooled analyses of data from 1,049,929 participants in 21 cohorts in Asia to quantify the risks of total and cause-specific mortality associated with tobacco smoking using adjusted hazard ratios and their 95% confidence intervals. We then estimated smoking-related deaths among adults aged ≥45 y in 2004 in Bangladesh, India, mainland China, Japan, Republic of Korea, Singapore, and Taiwan-accounting for ∼71% of Asia's total population. An approximately 1.44-fold (95% CI = 1.37-1.51) and 1.48-fold (1.38-1.58) elevated risk of death from any cause was found in male and female ever-smokers, respectively. In 2004, active tobacco smoking accounted for approximately 15.8% (95% CI = 14.3%-17.2%) and 3.3% (2.6%-4.0%) of deaths, respectively, in men and women aged ≥45 y in the seven countries/regions combined, with a total number of estimated deaths of ∼1,575,500 (95% CI = 1,398,000-1,744,700). Among men, approximately 11.4%, 30.5%, and 19.8% of deaths due to cardiovascular diseases, cancer, and respiratory diseases, respectively, were attributable to tobacco smoking. Corresponding proportions for East Asian women were 3.7%, 4.6%, and 1.7%, respectively. The strongest association with tobacco smoking was found for lung cancer: a 3- to 4-fold elevated risk, accounting for 60.5% and 16.7% of lung cancer deaths, respectively, in Asian men and East Asian women aged ≥45 y.

CONCLUSIONS

Tobacco smoking is associated with a substantially elevated risk of mortality, accounting for approximately 2 million deaths in adults aged ≥45 y throughout Asia in 2004. It is likely that smoking-related deaths in Asia will continue to rise over the next few decades if no effective smoking control programs are implemented. Please see later in the article for the Editors' Summary.

Meta-analyses using individual participant data from cardiovascular cohort studies in Japan: current status and future directions

Meta-analysis of individual participant data (IPD meta-analysis) has several advantages over meta-analysis using aggregated published data, including the possibility of using statistical methods such as a fine stratification analysis, interaction analysis between 2 risk factors, and absolute risk estimation. The Evidence for Cardiovascular Prevention from Observational Cohorts in Japan Study (EPOCH-JAPAN), which was initiated in 2005, is a collaborative research project for IPD meta-analysis and includes 13 participating cohort studies in Japan. We generated 2 pooled databases with data on all-cause mortality (n = 199 047) and cardiovascular outcomes (n = 90 528) and applied a stratified Cox model to account for the different baseline hazards between cohorts. The results of our analyses show the age- and sex-specific associations between all-cause and cardiovascular disease mortality and established cardiovascular risk factors (blood pressure, smoking, total cholesterol, proteinuria, and kidney function). During the 9 years of its existence, the results generated by EPOCH-JAPAN have had important implications for clinical medicine and public health policy in Japan. The project is expected to draw upon new analytical methods such as interaction analysis and absolute risk evaluation in the near future. We believe that, over the next decade, this project will continue to provide new insights that can be applied to research on other Asian populations.

Percentage of deaths attributable to poor cardiovascular health lifestyle factors: Findings from the Aerobics Center Longitudinal Study

PURPOSE

We assessed the effects of the four newly defined American Heart Association (AHA) lifestyle factors on mortality by examining the associated population attributable fractions (PAFs) of these factors.

METHODS

Slightly modified AHA cardiovascular health factors (smoking, BMI, cardiorespiratory fitness, and diet) were measured among 11,240 (24% women) participants from the Aerobics Center Longitudinal Study between 1987 and 1999. The cohort was followed to December 31, 2003 or death. PAFs were calculated as the proportionate reduction in death attributable to identified risk factors.

RESULTS

During an average 12 years of follow-up, 268 deaths occurred. Low fitness had the highest PAFs at the 5^th, 10^th, and 15^th year of follow-up, respectively: 6.6%, 6.4%, and 5.5%. Current smokers had the second highest PAFs at the 5^th, 10^th, and 15^th year of follow-up, respectively: 5.4%, 5.2%, and 5.0%. Additional adjusting for other confounders in the model did not change the above associations. The PAFs for overweight or obesity and unhealthy diet were not significant in the current analyses.

CONCLUSIONS

Assuming a causal relationship between smoking, low fitness and mortality, avoidance of both would have prevented 13% of the deaths in the current population. Preventive interventions to increase physical activity and stop smoking would most likely promote longevity.

Prediction of cardiovascular disease mortality by proteinuria and reduced kidney function: pooled analysis of 39,000 individuals from 7 cohort studies in Japan

There are limited studies addressing whether proteinuria and estimated glomerular filtration rate (eGFR) are independently associated with cardiovascular disease in Asia. Using data from 7 prospective cohorts recruited between 1980 and 1994 in Japan, we assessed the influence of proteinuria (≥1+ on dipstick) and reduced eGFR on the risk of cardiovascular disease mortality in 39,405 participants (40-89 years) without kidney failure. During a 10.1-year follow-up, 1,927 subjects died from cardiovascular disease. Proteinuria was associated with a 1.75-fold (95% confidence interval (CI): 1.44, 2.11) increased risk of cardiovascular disease mortality after adjustment for potential confounding factors. Additionally, the multivariate-adjusted hazard ratio of cardiovascular disease mortality increased linearly with lower eGFR levels (P(trend) < 0.001): Subjects with eGFR of <45 mL/minute/1.73 m² had a 2.22-fold (95% CI: 1.60, 3.07) greater risk of cardiovascular disease mortality than those with eGFR of ≥90 mL/minute/1.73 m². Subjects with both proteinuria and eGFR of <45 mL/minute/1.73 m² had a 4.05-fold (95% CI: 2.55, 6.43) higher risk of cardiovascular disease mortality compared with those with neither of these risk factors. There was no evidence of interaction in the relationship between proteinuria and lower eGFR (P(interaction) = 0.77). The present results suggest that proteinuria and lower eGFR are independent risk factors for cardiovascular disease mortality in the Japanese population.

Direct estimation of death attributable to smoking in Switzerland based on record linkage of routine and observational data

INTRODUCTION

In Switzerland, estimations of smoking-attributable deaths were based on age- and sex-adjusted hazard ratios (HRs) from foreign cohorts, precluding consideration of country-specific properties and adjustment for confounding. In order to overcome this, we analyzed recently available individual data from Switzerland.

METHODS

We included 17,861 individuals aged ≥16 years who participated between 1977-1993 in health studies and were anonymously linked with the Swiss National Cohort. Adjusted Cox regression was used to calculate mortality HRs. Smoking status at baseline was categorized into never-smokers, former smokers, and current light or heavy smokers (<20 or ≥20 cigarettes/day). As covariates, we selected education, marital status, lifestyle, alcohol consumption, and body mass index. We differentiated between cardiovascular disease (CVD), cancer, and noncancer-non-CVD deaths. Smoking-attributable deaths were estimated with a HR-based approach and with age-specific prevalence rates and mortality estimates from 2007.

RESULTS

Smoking men and women not only had an increased risk for all-cause (HR and 95% confidence interval vs. never-smokers: 1.71 [1.53-1.90]; 1.54 [1.36-1.75]), CVD (1.72 [1.43-2.06]; 1.50 [1.19-1.90]) and cancer (1.87 [1.56-2.25]; 1.58 [1.30-1.93]), but also for noncancer-non-CVD death (1.57 [1.29-1.89]; 1.58 [1.30-1.93]). Former smoking men had an increased risk for all-cause (1.16 [1.03-1.31]) and cancer death (1.35 [1.10-1.65]). Multivariate adjustment only slightly modified the association between smoking and mortality. Overall, 7,153 deaths per year could be attributed to smoking.

CONCLUSIONS

Smoking is an important avoidable health burden in Switzerland, and its consequences may persist for decades after quitting. This stresses the need for putting more efforts in strategies aimed at preventing the onset of smoking.

Smoking and mortality among persons aged 75-94

OBJECTIVES

Examine the effect of current level of smoking and lifetime tobacco consumption on mortality in persons 75-94 years of age.

METHODS

Data were from a representative sample of older Jewish persons in Israel, which included 1,200 self-respondent participants aged 75-94 (Mean=83.1, SD=5.3) from the Cross-Sectional and Longitudinal Aging Study (CALAS). Data collection took place during 1989-1992. Mortality data on 95.1% of the sample at 20-year follow up were recorded from the Israeli National Population Registry.

RESULTS

The following variables adversely affected mortality for the whole sample: Smoking 11-20 cigarettes daily (HR=1.276, p<.05), smoking over 20 cigarettes daily (HR=1.328, p<.05), total tobacco consumption (HR=1.002, p<.01), and heavy lifetime tobacco consumption (HR=1.270, p<.01). Results were similar for persons aged 75-84, but the effect of smoking seems to decrease or disappear for ages 85 and above.

CONCLUSION

This is the first report of all-cause mortality risk in both genders of a representative population aged 75 and over. Increased mortality risk is related to high daily quantity of current smoking, and to cumulative amount of lifetime smoking. The effect of smoking may disappear for ages 85 and above, and should be studied in larger oldest-old samples.

Impact of smoking on mortality and life expectancy in Japanese smokers: a prospective cohort study

OBJECTIVE

To investigate the impact of smoking on overall mortality and life expectancy in a large Japanese population, including some who smoked throughout adult life.

DESIGN

The Life Span Study, a population-based prospective study, initiated in 1950.

SETTING

Hiroshima and Nagasaki, Japan.

PARTICIPANTS

Smoking status for 27,311 men and 40,662 women was obtained during 1963-92. Mortality from one year after first ascertainment of smoking status until 1 January 2008 has been analysed.

MAIN OUTCOME MEASURES

Mortality from all causes in current, former, and never smokers.

RESULTS

Smokers born in later decades tended to smoke more cigarettes per day than those born earlier, and to have started smoking at a younger age. Among those born during 1920-45 (median 1933) and who started smoking before age 20 years, men smoked on average 23 cigarettes/day, while women smoked 17 cigarettes/day, and, for those who continued smoking, overall mortality was more than doubled in both sexes (rate ratios versus never smokers: men 2.21 (95% confidence interval 1.97 to 2.48), women 2.61 (1.98 to 3.44)) and life expectancy was reduced by almost a decade (8 years for men, 10 years for women). Those who stopped smoking before age 35 avoided almost all of the excess risk among continuing smokers, while those who stopped smoking before age 45 avoided most of it.

CONCLUSIONS

The lower smoking related hazards reported previously in Japan may have been due to earlier birth cohorts starting to smoke when older and smoking fewer cigarettes per day. In Japan, as elsewhere, those who start smoking in early adult life and continue smoking lose on average about a decade of life. Much of the risk can, however, be avoided by giving up smoking before age 35, and preferably well before age 35.

Relation between serum total cholesterol level and cardiovascular disease stratified by sex and age group: a pooled analysis of 65 594 individuals from 10 cohort studies in Japan

BACKGROUND

The relation between serum total cholesterol (TC) and cardiovascular disease in women and in the elderly is unclear, especially in Asian populations.

METHODS AND RESULTS

We examined this relation in the largest-scale pooled analysis of the Japanese population, the Evidence for Cardiovascular Prevention from Observational Cohorts in Japan (EPOCH-JAPAN) study. A total of 65 594 participants who were 40 to 89 years of age and did not have a past history of cardiovascular disease were examined. Cox proportional-hazards models were used to estimate hazard ratios for death from total stroke, cerebral infarction, intracranial cerebral hemorrhage, or coronary heart disease. The mean follow-up period was 10.1 years, with the number of deaths from total stroke, cerebral infarction, cerebral hemorrhage, and coronary heart disease being 875, 457, 212, and 374, respectively. The participants were divided into 2 age groups: middle-aged (40 to 69 years; mean age 55 years) and elderly (70 to 89 years; mean age 75 years). In men, the multivariate-adjusted hazard ratios for coronary heart disease in the highest TC category (≥6.21 mmol/L) compared with the lowest category (<4.14 mmol/L) were 2.52 (95% confidence interval: 1.15-5.07) in middle-aged participants and 2.77 (1.09-7.03) in elderly participants. In women, the hazard ratios of the highest TC category (≥6.72 mmol/L) compared with the lowest category (<4.66 mmol/L) were 3.20 (1.44-7.09) in middle-aged participants and 1.02 (0.42-2.49) in elderly participants. TC levels were not associated with cerebral infarction in any age or sex group and were associated negatively with total stroke and cerebral hemorrhage.

CONCLUSION

High serum TC levels are associated with coronary heart disease in middle-aged Japanese men and women, but evidence in elderly Japanese individuals is still limited.

Blood pressure categories and long-term risk of cardiovascular disease according to age group in Japanese men and women

Blood pressure (BP) categories defined by systolic BP (SBP) and diastolic BP (DBP) are commonly used. However, the BP category-specific risk of cardiovascular disease (CVD) has not been thoroughly investigated in different age groups. The aim of this study was to assess long-term CVD risk and its impact according to BP categories and age group. Pooling individual data from 10 cohorts, we studied 67 309 Japanese individuals (40-89 years old) who were free of CVD at baseline: we categorized them as belonging to three age groups: 'middle-aged' (40-64 years), 'elderly' (65-74 years) and 'very elderly' (75-89 years). BP was classified according to the 2009 Japanese Society of Hypertension Guidelines. Cox models were used to estimate adjusted hazard ratios for CVD deaths. We observed 1944 CVD deaths over a mean follow-up of 10.2 years. In all age groups, the overall relationship between BP category and CVD risk was positive, with a greater strength observed for younger age groups. We observed a trend of increased risk from SBP/DBP ≥ 130/85 mm Hg in the very elderly, and a significant increase from SBP/DBP ≥ 120/80 mm Hg in the other age groups. The population attributable fractions (PAFs) of CVD death in reference to the SBP/DBP<120/80 mm Hg category ranged from 23.4% in the very elderly to 60.3% in the middle-aged. We found an overall graded increase in CVD risk with higher BP category in the very elderly. The PAFs suggest that keeping BP levels low is an important strategy for primary CVD prevention, even in an elderly population.

Influence of smoking combined with another risk factor on the risk of mortality from coronary heart disease and stroke: pooled analysis of 10 Japanese cohort studies

BACKGROUND

In spite of the importance of a multifactorial approach to preventing cardiovascular disease in smokers, most information on the combined adverse effects of smoking and hypertension or high serum cholesterol on cardiovascular disease has been derived from Western populations, and coronary heart disease was often used as the only endpoint. Therefore, the present large-scale pooled analysis attempted to provide reliable information on the adverse effects of the coexistence of smoking and hypertension or high serum cholesterol on the risk of mortality from coronary heart disease and stroke in both, individuals and the entire population in Japan.

METHODS

A total of 27,385 male and 39,207 female participants aged 40-89 years were enrolled from 10 well-qualified Japanese cohort studies with a mean follow-up of 10.1 years. Hazard ratios and their corresponding 95% confidence intervals in smokers who had hypertension or high serum cholesterol were estimated for men and women separately using a Cox proportional hazards regression model that included age, body mass index, cohort and either serum total cholesterol or systolic blood pressure as covariates. Fractions of deaths attributable to the coexistence of these risk factors were also calculated.

RESULTS

The multivariate-adjusted hazard ratios in male and female current smokers with hypertension, compared with those with neither factor were 2.57 (95% confidence intervals, 1.51-4.38) and 6.14 (3.49-10.79) for coronary heart disease, and 3.28 (1.89-5.71) and 1.61 (0.81-3.18) for cerebral infarction, respectively. The fractions of deaths attributable to the coexistence of current smoking and hypertension in men and women were 24.6 and 9.6% for coronary heart disease and 28.1 and 2.0% for cerebral infarction, respectively. Smokers with high serum cholesterol were broadly comparable to hypertensive smokers only with respect to coronary mortality risk; the hazard ratios, compared with those with neither factor were 4.19 (2.33-7.53) for men and 3.90 (1.57-9.67) for women. The fraction of coronary deaths attributable to the coexistence of current smoking and high serum cholesterol was 6.3% in men and 2.2% in women. There was no interaction between smoking habit and blood pressure or serum total cholesterol for these two subtypes in both men and women.

CONCLUSIONS

Particular attention should be given to smokers who have concomitant hypertension or high serum cholesterol for preventing deaths due to cardiovascular disease. From a public health perspective in Japan, priority should be given to hypertensive smokers, since this group makes a large contribution to the burden of both coronary and cerebral infarction deaths.

Adult mortality attributable to preventable risk factors for non-communicable diseases and injuries in Japan: a comparative risk assessment

BACKGROUND

The population of Japan has achieved the longest life expectancy in the world. To further improve population health, consistent and comparative evidence on mortality attributable to preventable risk factors is necessary for setting priorities for health policies and programs. Although several past studies have quantified the impact of individual risk factors in Japan, to our knowledge no study has assessed and compared the effects of multiple modifiable risk factors for non-communicable diseases and injuries using a standard framework. We estimated the effects of 16 risk factors on cause-specific deaths and life expectancy in Japan.

METHODS AND FINDINGS

We obtained data on risk factor exposures from the National Health and Nutrition Survey and epidemiological studies, data on the number of cause-specific deaths from vital records adjusted for ill-defined codes, and data on relative risks from epidemiological studies and meta-analyses. We applied a comparative risk assessment framework to estimate effects of excess risks on deaths and life expectancy at age 40 y. In 2007, tobacco smoking and high blood pressure accounted for 129,000 deaths (95% CI: 115,000-154,000) and 104,000 deaths (95% CI: 86,000-119,000), respectively, followed by physical inactivity (52,000 deaths, 95% CI: 47,000-58,000), high blood glucose (34,000 deaths, 95% CI: 26,000-43,000), high dietary salt intake (34,000 deaths, 95% CI: 27,000-39,000), and alcohol use (31,000 deaths, 95% CI: 28,000-35,000). In recent decades, cancer mortality attributable to tobacco smoking has increased in the elderly, while stroke mortality attributable to high blood pressure has declined. Life expectancy at age 40 y in 2007 would have been extended by 1.4 y for both sexes (men, 95% CI: 1.3-1.6; women, 95% CI: 1.2-1.7) if exposures to multiple cardiovascular risk factors had been reduced to their optimal levels as determined by a theoretical-minimum-risk exposure distribution.

CONCLUSIONS

Tobacco smoking and high blood pressure are the two major risk factors for adult mortality from non-communicable diseases and injuries in Japan. There is a large potential population health gain if multiple risk factors are jointly controlled.

What has made the population of Japan healthy?

People in Japan have the longest life expectancy at birth in the world. Here, we compile the best available evidence about population health in Japan to investigate what has made the Japanese people healthy in the past 50 years. The Japanese population achieved longevity in a fairly short time through a rapid reduction in mortality rates for communicable diseases from the 1950s to the early 1960s, followed by a large reduction in stroke mortality rates. Japan had moderate mortality rates for non-communicable diseases, with the exception of stroke, in the 1950s. The improvement in population health continued after the mid-1960s through the implementation of primary and secondary preventive community public health measures for adult mortality from non-communicable diseases and an increased use of advanced medical technologies through the universal insurance scheme. Reduction in health inequalities with improved average population health was partly attributable to equal educational opportunities and financial access to care. With the achievement of success during the health transition since World War 2, Japan now needs to tackle major health challenges that are emanating from a rapidly ageing population, causes that are not amenable to health technologies, and the effects of increasing social disparities to sustain the improvement in population health.