Association between reproductive factors with lung cancer incidence and mortality: A pooled analysis of over 308,000 females in the Asia cohort consortium

Previous studies have investigated the association between reproductive factors and lung cancer risk; however, findings have been inconsistent. In order to assess this association among Asian women, a total of 308,949 female participants from 11 prospective cohorts and four Asian countries (Japan, Korea, China, and Singapore) were included. Cox proportional hazards regression models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CIs). A total of 3,119 primary lung cancer cases and 2247 lung cancer deaths were identified with a mean follow-up of 16.4 years. Parous women had a lower risk of lung cancer incidence and mortality as compared with nulliparous women, with HRs of 0.82 (95% CI = 0.70-0.96) and 0.78 (95% CI = 0.65-0.94). The protective association of parity and lung cancer incidence was greater among ever-smokers (HR = 0.66, 95% CI = 0.49-0.87) than in never-smokers (HR = 0.90, 95% CI = 0.74-1.09) (P-interaction = 0.029). Compared with age at first delivery ≤20 years, older age at first delivery (21-25, ≥26 years) was associated with a lower risk of lung cancer incidence and mortality. Women who ever used hormone replacements had a higher likelihood of developing non-small cell lung cancer (HR = 1.31, 95% CI = 1.02-1.68), compared to those who never used hormone replacements. Future studies are needed to assess the underlying mechanisms, the relationships within these female reproductive factors, and the potential changes in smoking habits over time.

Diabetes is associated with increased liver cancer incidence and mortality in adults: A report from Asia Cohort Consortium

There has been growing evidence suggesting that diabetes may be associated with increased liver cancer risk. However, studies conducted in Asian countries are limited. This project considered data of 968,738 adults pooled from 20 cohort studies of Asia Cohort Consortium to examine the association between baseline diabetes and liver cancer incidence and mortality. Cox proportional hazard model and competing risk approach was used for pooled data. Two-stage meta-analysis across studies was also done. There were 839,194 subjects with valid data regarding liver cancer incidence (5654 liver cancer cases [48.29/100,000 person-years]), follow-up time and baseline diabetes (44,781 with diabetes [5.3%]). There were 747,198 subjects with valid data regarding liver cancer mortality (5020 liver cancer deaths [44.03/100,000 person-years]), follow-up time and baseline diabetes (43,243 with diabetes [5.8%]). Hazard ratio (HR) (95% confidence interval [95%CI]) of liver cancer diagnosis in those with vs. without baseline diabetes was 1.97 (1.79, 2.16) (p < .0001) after adjusting for baseline age, gender, body mass index, tobacco smoking, alcohol use, and heterogeneity across studies (n = 586,072; events = 4620). Baseline diabetes was associated with increased cumulative incidence of death due to liver cancer (adjusted HR (95%CI) = 1.97 (1.79, 2.18); p < .0001) (n = 595,193; events = 4110). A two-stage meta-analytic approach showed similar results. This paper adds important population-based evidence to current literature regarding the increased incidence and mortality of liver cancer in adults with diabetes. The analysis of data pooled from 20 studies of different Asian countries and the meta-analysis across studies with large number of subjects makes the results robust.

Active and passive smoking and breast cancer in Japan: a pooled analysis of nine population-based cohort studies

BACKGROUND

Epidemiological studies have shown inconsistent results regarding the link between smoking and breast cancer risk, despite the biological plausibility of a positive association.

METHODS

Participants were 166 611 women from nine prospective cohort studies in Japan which launched in 1984-1994 and followed for 8-22 years. Information on smoking and secondhand smoke was obtained through self-administered baseline questionnaires. Breast cancer was defined as code C50 according to the International Classification of Diseases for Oncology, 3rd Edition or the International Classification of Diseases, 10th Revision. After adjusting for several potential confounders, relative risks for breast cancer were calculated in the individual studies according to the current or previous status of active and passive smoking using Cox regression, followed by a summary estimate of hazard ratios using random-effects meta-analyses.

RESULTS

Of the 60 441 participants who reported being premenopausal and 106 170 who reported being postmenopausal at baseline, 897 and 1168 developed breast cancer during follow-up, respectively. Compared with never smokers, current smokers had a higher risk of developing breast cancer before the age of 50 years. In addition, ever smokers who started smoking at 30 years of age or younger, or who started smoking before first childbirth, had a higher risk of developing breast cancer before the age of 50 years. No association between adulthood or childhood exposure to secondhand smoke and breast cancer was observed.

CONCLUSION

Smoking may increase the risk of premenopausal breast cancer, and smoking earlier in life might be especially harmful. The impact of secondhand smoke needs further investigation.

Obesity is associated with biliary tract cancer mortality and incidence: A pooled analysis of 21 cohort studies in the Asia Cohort Consortium

Body fatness is considered a probable risk factor for biliary tract cancer (BTC), whereas cholelithiasis is an established factor. Nevertheless, although obesity is an established risk factor for cholelithiasis, previous studies of the association of body mass index (BMI) and BTC did not take the effect of cholelithiasis fully into account. To better understand the effect of BMI on BTC, we conducted a pooled analysis using population-based cohort studies in Asians. In total, 905 530 subjects from 21 cohort studies participating in the Asia Cohort Consortium were included. BMI was categorized into four groups: underweight (<18.5 kg/m2 ); normal (18.5-22.9 kg/m2 ); overweight (23-24.9 kg/m2 ); and obese (25+ kg/m2 ). The association between BMI and BTC incidence and mortality was assessed using hazard ratios (HR) and 95% confidence intervals (CIs) by Cox regression models with shared frailty. Mediation analysis was used to decompose the association into a direct and an indirect (mediated) effect. Compared to normal BMI, high BMI was associated with BTC mortality (HR 1.19 [CI 1.02-1.38] for males, HR 1.30 [1.14-1.49] for females). Cholelithiasis had significant interaction with BMI on BTC risk. BMI was associated with BTC risk directly and through cholelithiasis in females, whereas the association was unclear in males. When cholelithiasis was present, BMI was not associated with BTC death in either males or females. BMI was associated with BTC death among females without cholelithiasis. This study suggests BMI is associated with BTC mortality in Asians. Cholelithiasis appears to contribute to the association; and moreover, obesity appears to increase BTC risk without cholelithiasis.

Body mass index and lung cancer risk: Pooled analysis of 10 prospective cohort studies in Japan

Mounting evidence suggests that body mass index (BMI) is inversely associated with the risk of lung cancer. However, relatively few studies have explored this association in Asian people, who have a much lower prevalence of obesity than Caucasians. We pooled data from 10 prospective cohort studies involving 444,143 Japanese men and women to address the association between BMI and the risk of lung cancer. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated in each cohort using the Cox proportional hazards model. A meta-analysis was undertaken by combining the results from each cohort. Heterogeneity across studies was evaluated using Cochran's Q and I2statistics. During 5,730,013 person-years of follow-up, 6454 incident lung cancer cases (4727 men and 1727 women) were identified. Baseline BMI was inversely associated with lung cancer risk in men and women combined. While leanness (BMI <18.5) was associated with a higher risk of lung cancer (HR 1.35; 95% CI, 1.16-1.57), overweight and obesity were associated with a lower risk, with HRs of 0.77 (95% CI, 0.71-0.84) and 0.69 (95% CI, 0.45-1.07), respectively. Every 5 kg/m2 increase in BMI was associated with a 21% lower risk of lung cancer (HR 0.79; 95% CI, 0.75-0.83; p < 0.0001). Our pooled analysis indicated that BMI is inversely associated with the risk of lung cancer in the Japanese population. This inverse association could be partly attributed to residual confounding by smoking, as it was more pronounced among male smokers.

Combined Fat Mass and Fat-free Mass Indices and Lung Function Among Japanese Population: The Tohoku Medical Megabank Community-based Cohort Study

BACKGROUND

Although fat mass index (FMI) and fat-free mass index (FFMI) affect lung function, FMI and FFMI are not independent of each other, since FMI and FFMI were calculated as fat mass and fat-free mass divided by height squared, respectively. We aimed to examine the association of combined FMI and FFMI with lung function.

METHODS

In this cross-sectional study, lung function was evaluated using forced expiratory volume at 1 s (FEV1) and forced vital capacity (FVC) measured using spirometry. Both FMI and FFMI were classified into sex-specific quartiles (16 groups). Analysis of covariance was used to assess the associations of combined FMI and FFMI with lung function. The trend test was conducted by stratifying the FMI and FFMI, scoring the categories from 1-4 (lowest-highest), and entering the number as a continuous term in the regression model.

RESULTS

This study included 3,736 men and 8,821 women aged ≥20 years living in Miyagi Prefecture, Japan. The mean FEV1 was 3.0 (standard deviation [SD], 0.7) L for men and 2.3 (SD, 0.5) L for women. The mean FVC was 3.8 (SD, 0.7) L for men and 2.8 (SD, 0.5) L for women. FMI was inversely associated with lung function among all FFMI subgroups in both sexes. Conversely, FFMI was positively associated with lung function in all FMI subgroups in both sexes.

CONCLUSION

Higher FMI was associated with lower lung function independent of FFMI; higher FFMI was associated with higher lung function independent of FMI. Reducing FMI and maintaining FFMI might be important for respiratory health.

Lung Cancer Risk Prediction Models for Asian Ever-Smokers

INTRODUCTION

Although lung cancer prediction models are widely used to support risk-based screening, their performance outside Western populations remains uncertain. This study aims to evaluate the performance of 11 existing risk prediction models in multiple Asian populations and to refit prediction models for Asians.

METHODS

In a pooled analysis of 186,458 Asian ever-smokers from 19 prospective cohorts, we assessed calibration (expected-to-observed ratio) and discrimination (area under the receiver operating characteristic curve [AUC]) for each model. In addition, we developed the "Shanghai models" to better refine risk models for Asians on the basis of two well-characterized population-based prospective cohorts and externally validated them in other Asian cohorts.

RESULTS

Among the 11 models, the Lung Cancer Death Risk Assessment Tool yielded the highest AUC (AUC [95% confidence interval (CI)] = 0.71 [0.67-0.74] for lung cancer death and 0.69 [0.67-0.72] for lung cancer incidence) and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial Model had good calibration overall (expected-to-observed ratio [95% CI] = 1.06 [0.90-1.25]). Nevertheless, these models substantially underestimated lung cancer risk among Asians who reported less than 10 smoking pack-years or stopped smoking more than or equal to 20 years ago. The Shanghai models were found to have marginal improvement overall in discrimination (AUC [95% CI] = 0.72 [0.69-0.74] for lung cancer death and 0.70 [0.67-0.72] for lung cancer incidence) but consistently outperformed the selected Western models among low-intensity smokers and long-term quitters.

CONCLUSIONS

The Shanghai models had comparable performance overall to the best existing models, but they improved much in predicting the lung cancer risk of low-intensity smokers and long-term quitters in Asia.

Adult Height and Risk of Colorectal Cancer: A Pooled Analysis of 10 Population-based Cohort Studies in Japan

BACKGROUND

While tall stature has been linked to an increase in the risk of colorectal cancer (CRC), its association with cancer in the colorectum and its subsites remains unclear among Asians.

METHODS

We conducted a pooled analysis of 10 population-based cohort studies among adults in Japan. Each study estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC incidence associated with adult height were estimated using Cox proportional hazards regression with adjustment of the same set of covariates were then pooled to estimate summary HRs incidence using random-effect models.

RESULTS

We identified 9,470 CRC incidences among 390,063 participants during 5,672,930 person-years of follow-up. Men and women with tall stature had a higher risk of CRC and colon cancer. HRs for CRC, colon cancer, and distal colon cancer for the highest versus lowest height categories were 1.23 (95% CI, 1.07-1.40), 1.22 (95% CI, 1.09-1.36), and 1.27 (95% CI, 1.08-1.49), respectively, in men and 1.21 (95% CI, 1.09-1.35), 1.23 (95% CI, 1.08-1.40), and 1.35 (95% CI, 1.003-1.81), respectively, in women. The association with proximal colon cancer and rectal cancer was less evident in both sexes.

CONCLUSION

This pooled analysis confirms the link between tall stature and a higher risk of CRC and colon cancer (especially distal colon) among the Japanese and adds evidence to support the use of adult height to identify those at a higher risk of CRC.

Association between Social Isolation and the Risk of Incident Functional Disability in Elderly Survivors after the Great East Japan Earthquake

Social isolation is frequently observed among survivors of disaster. However, there is limited evidence regarding the association between social isolation and adverse health outcomes among survivors of disaster. The purpose of this study was to investigate the association between social isolation and the risk of incident functional disability (IFD) among survivors of the 2011 Great East Japan Earthquake (GEJE). We conducted a prospective cohort study of 1,039 residents aged ≥ 65 years who lived in four areas affected by the GEJE. Information regarding social isolation and other lifestyle factors was collected between June and November 2011 via a self-reported questionnaire. Social isolation was assessed using the Lubben Social Network Scale-6 (LSNS-6). Data regarding the incidence of functional disability were retrieved from the Long-term Care Insurance database. The Cox model was used to calculate multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) for IFD. During 7,030 person-years of follow-up, 300 cases of IFD were certified (42.7disability events per 1,000 person-years). Social isolation was associated with increased risk of IFD in disaster survivors (HR = 1.32, 95% CI = 0.98-1.76). In addition, this association tended to be more remarkable among men and those whose houses were completely/seriously damaged. The present results suggest us that it would be possible to identify those who are more likely to be affected by social isolation after disaster. This finding would be useful in screening and supporting high risk group right after the occurrence of disaster.

Association of Central Blood Pressure and Carotid Intima Media Thickness with New-Onset Hypertension in People with High Normal Blood Pressure

AIM

People with high normal blood pressure (BP) have a higher risk of cardiovascular events than those with normal BP; therefore, progression to hypertension (HT) should be prevented. We aimed to assess the HT risk using central BP and carotid intima media thickness (CIMT) in people with high normal BP.

METHODS

This prospective cohort study used the Tohoku Medical Megabank Community-Based Project Cohort Study (conducted from 2013 in Miyagi Prefecture in Japan). The participants had a high normal BP, defined as a systolic BP of 120-139 mmHg and diastolic BP ＜90 mmHg using brachial BP measurement during the baseline survey. The outcome was new-onset HT during the secondary survey, conducted four years after the baseline survey.

RESULTS

Overall, 4,021 participants with high normal BP during the baseline survey, with an average age of 58.7 years, were included; 1,030 (26%) were diagnosed with new-onset HT during the secondary survey, 3.5±0.7 years after the baseline survey. The multivariable odds ratio (95% confidence interval) for HT in the highest versus lowest quartile of central BP was 1.7 (1.2-2.4, p=0.0030), and that of CIMT was 1.8 (1.4-2.4, p＜0.001). Subgroup analysis according to age (＜60 and ≥ 60 years) and sex revealed that the central BP was influential in groups with younger age and female individuals; CIMT was influential in all groups.

CONCLUSIONS

Higher central BP and thicker CIMT at the baseline were correlated with new-onset HT in individuals with high normal BP, independent of brachial systolic BP and other cardiovascular risk factors.

Influence of Diabetes Family History on the Associations of Combined Genetic and Lifestyle Risks with Diabetes in the Tohoku Medical Megabank Community-Based Cohort Study

AIM

The influence of family history of diabetes, probably reflecting genetic and lifestyle factors, on the association of combined genetic and lifestyle risks with diabetes is unknown. We examined these associations.

METHODS

This cross-sectional study included 9,681 participants in the Tohoku Medical Megabank Community-based Cohort Study. A lifestyle score, which was categorized into ideal, intermediate, and poor lifestyles, was given. Family history was obtained through a self-reported questionnaire. A polygenic risk score (PRS) was constructed in the target data (n=1,936) using publicly available genome-wide association study summary statistics from BioBank Japan. For test data (n=7,745), we evaluated PRS performance and examined the associations of combined family history and genetic and lifestyle risks with diabetes. Diabetes was defined as non-fasting blood glucose ≥ 200 mmHg, HbA1c ≥ 6.5%, and/or self-reported diabetes treatment.

RESULTS

In test data, 467 (6.0%) participants had diabetes. Compared with a low genetic risk and an ideal lifestyle without a family history, the odds ratio (OR) was 3.73 (95% confidence interval [CI], 1.92-7.00) for a lower genetic risk and a poor lifestyle without a family history. Family history was significantly associated with diabetes (OR, 3.58 [95% CI, 1.73-6.98]), even in those with a low genetic risk and an ideal lifestyle. Even among participants who had an ideal lifestyle without a family history, a high genetic risk was associated with diabetes (OR, 2.49 [95% CI, 1.65-3.85]). Adding PRS to family history and conventional lifestyle risk factors improved the prediction ability for diabetes.

CONCLUSIONS

Our findings support the notion that a healthy lifestyle is important to prevent diabetes regardless of genetic risk.

Cigarette Smoking, Smoking Cessation, and Bladder Cancer Risk: A Pooled Analysis of 10 Cohort Studies in Japan

BACKGROUND

Although cigarette smoking is an established risk factor for bladder cancer, assessment of smoking impact on bladder cancer in Asian populations has been hindered by few cohort studies conducted in Asian populations. Therefore, we investigated the risk of bladder cancer associated with smoking status, cumulative smoking intensity, and smoking cessation in Japan.

METHODS

We analyzed data for 157,295 men and 183,202 women in 10 population-based cohort studies in Japan. The risk associated with smoking behaviors was estimated using Cox regression models within each study, and pooled hazard ratios (HRs) and their 95% confidence intervals (CIs) for the incidence of bladder cancer were calculated.

RESULTS

During 4,729,073 person-years of follow-up, 936 men and 325 women developed bladder cancer. In men, former smokers (HR 1.47; 95% CI, 1.18-1.82) and current smokers (HR 1.96; 95% CI, 1.62-2.38) had higher risk than never smokers. In women, current smokers had higher risk than never smokers (HR 2.35; 95% CI, 1.67-3.32). HRs in men linearly increased with increasing pack-years. Risk decreased with increasing years of smoking cessation in men, with a significant dose-response trend. Former smokers with a duration of more than 10 years after smoking cessation had no significantly increased risk compared with never smokers (HR 1.26; 95% CI, 0.97-1.63).

CONCLUSION

Data from a pooled analysis of 10 population-based cohort studies in Japan clearly show an association between cigarette smoking and bladder cancer risk. The risk of smokers may approximate that of never smokers following cessation for many years.

Carotid Intima Media Thickness and Risk Factor for Atherosclerosis: Tohoku Medical Megabank Community-Based Cohort Study

AIM

We examined the association between the carotid intima medica thickness (cIMT) and risk factors for atherosclerosis based on the Japan Atherosclerosis Society 2022 Atherosclerosis Prevention Guideline.

METHODS

Using data from the Tohoku Medical Megabank Community-based Cohort Study, we performed a cross-sectional study that enrolled 13,366 participants (age ≥ 20 years) with an analysis of covariance to assess associations between cIMT and risk factors for atherosclerosis. The maximum common carotid artery was measured using high-resolution B-mode ultrasound. Analysis was conducted in the model adjusted for age, sex, smoking status, drinking status, body mass index (BMI), systolic blood pressure (SBP), glycated hemoglobin (HbA1c), high-density lipoprotein-cholesterol (HDL-C), non-high-density lipoprotein-cholesterol (non-HDL-C), and height.

RESULTS

In this study cohort, the average age and cIMT were 57.3 (13.8) years and 0.61 (0.13) mm, respectively, which included 3,988 males (29.8%). Males had a higher cIMT than did the females. Age, height, BMI, SBP, HbA1c, and non-HDL-C were positively associated with cIMT. HDL-C was inversely associated with cIMT. Compared with never drinkers, current drinkers (≥ 46.0 g/day) had a significantly decreased cIMT.

CONCLUSIONS

The cIMT was associated with atherosclerosis risk factors including age, sex, BMI, SBP, HbA1c, non-HDL-C, and HDL-C, and adequate control of risks in high-risk individuals might be required to prevent atherosclerotic cardiovascular diseases.

Association between dairy intake and risk of incident dementia: the Ohsaki Cohort 2006 Study

PURPOSE

To investigate the association between dairy intake and risk of incident dementia in older adults.

METHODS

A longitudinal analysis of dairy intake with incident dementia was conducted using a cohort study of 11,637 non-disabled Japanese older adults aged ≥ 65 years followed-up for up to 5.7 years (mean: 5.0 years). Data on milk, yogurt, and cheese intake were collected using a validated food frequency questionnaire. Total dairy intake was calculated as the sum of the daily intake of milk, yogurt, and cheese, which was sex-specifically categorized in quintiles. Dementia cases were retrieved from the public long-term care insurance database. Cox proportional hazards model was used to estimate multivariable hazard ratios (HRs) and 95% confidence intervals (95% CIs) for incident dementia.

RESULTS

During 58,013 person-years of follow-up, 946 persons developed dementia. In the primary analysis, compare to the lowest quintile of total dairy intake, Q2 showed a slightly decreased incident dementia risk (HR for Q2 vs Q1: 0.90, 95% CI: 0.73-1.10) after fully adjusted for demographic, lifestyle, psychological, and nutritional factors, and diseases history. Compared to non-consumers of milk, those consuming for 1-2 times/month showed a lower risk of incident dementia (fully-adjusted HR: 0.76, 95% CI: 0.57-1.02). Daily yogurt consumers also had a reduced risk (fully-adjusted HR: 0.89, 95% CI: 0.74-1.09). But daily cheese consumers showed an increased risk of dementia (fully-adjusted HR: 1.28, 95% CI: 0.91-1.79). In the sensitivity analysis where we excluded dementia cases ascertained in the first 2 years, results were consistent with those from the primary analysis and we further found that yogurt intake might be inversely associated with dementia risk (p for trend = 0.025).

CONCLUSION

Low total dairy intake or low milk intake frequency might be associated with lower incident dementia risk, however daily cheese consumers seemed to have an increased risk. Our study also suggested a possible inverse dose-response association between yogurt consumption and dementia risk, but further studies are needed to confirm whether this benefit was from yogurt intake itself or as a part of a healthy dietary pattern.

Sleep duration and the risk of endometrial cancer incidence among Japanese women: A pooled analysis of the Miyagi Cohort Study and the Ohsaki Cohort Study

OBJECTIVE

Endometrial cancer has been increasing worldwide, and is one of the most common female hormone-related cancers. The purpose of this study was to examine the association between sleep duration and risk of endometrial cancer among Japanese women.

METHODS

We conducted a pooled analysis of two prospective studies conducted among residents of Miyagi Prefecture in rural northern Japan. A total of 36,537 women aged 40-79 years participated in the Miyagi Cohort Study in 1990 and in the Ohsaki Cohort Study in 1994. The participants responded to a self-administered questionnaire that including sleep duration. Sleep duration was assessed at the baseline using a self-administered questionnaire. The participants entered the mean integer number representing the hours of sleep taken per day during the previous year. We divided the participants into three groups (≤6 h, 7-8 h, or ≥9 h). Cox proportional hazards regression analysis was used to estimate the multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) for endometrial cancer incidence.

RESULTS

During 745,993 person-years of follow-up, we identified 146 incident cases of endometrial cancer. Compared with women who slept 7-8 h per day, the multivariate HR (95%CI) for endometrial cancer incidence was 1.07 (0.72-1.60) for those who slept 6 h or less, and 1.05 (0.57-1.93) for those who slept 9 h or longer (p-trend=0.57).

CONCLUSION

In analysis of two population -based prospective cohort studies conducted among Japanese women, we found no significant associations between sleep duration and the incidence of endometrial cancer.

Association between psychological distress and disability-free life expectancy in the older Japanese adults

BACKGROUND

Our study aimed to investigate the association between psychological distress and disability-free life expectancy (DFLE).

METHODS

In 2006, a cohort study was conducted of 12,365 Japanese individuals aged ≥65 years, who were followed-up for 13 years. Psychological distress was measured using the Kessler 6-item psychological distress scale and was categorized into no (0-4), mild (5-9), moderate (10-12), and serious distress (13-24). The number of participants was 1277 (22.4 %) for mild distress, 330 (5.8 %) for moderate, and 208 (3.6 %) for serious in men, and was 1635 (24.6 %), 467 (7.0 %), and 384 (5.8 %) in women. Sex-specific DFLE was defined as the mean years a person could expect to live without disability and calculated by Interpolated Markov Chain (IMaCh) software.

RESULTS

Compared to no distress, DFLE loss per person was 1.21, 2.61, and 4.43 years for mild, moderate, and serious distress respectively in men. At population level, DFEL loss (i.e., DFLE loss per person×number of participants) was 1545.17, 861.30, and 921.44 years for mild, moderate, and serious distress respectively in men. Accordingly, 46.4 % of the total DFLE loss was attributable to mild distress, 25.9 % to moderate, and 27.7 % to serious in men. Similarly, the results were 42.2 %, 25.4 %, and 32.4 % in women.

LIMITATIONS

Psychological distress was measured only once at baseline, and 2409 participants were excluded from the analysis because of missing data on exposure.

CONCLUSIONS

At population level, almost half of the total DFLE loss could be attributable to mild distress, underscoring the importance of population strategy for all levels of distress in promoting healthy aging.

Association between Low Back Pain and Neck Pain: A 3-Year Longitudinal Study Using the Data of the People after the Great East Japan Earthquake

Low back pain (LBP) and neck pain (NP) are common health problems worldwide. LBP often coexists with NP; however, the association between these pains remains unclear. The purpose of this study was to clarify the association between LBP and NP, focusing on dose-dependent effects. This study used a 3-year longitudinal cohort data of people living in disaster-stricken areas after the Great East Japan Earthquake (n = 2,118). LBP and NP were assessed at 4, 5, 6, and 7 years after the disaster. LBP was categorized according to its frequency. Multivariate logistic regression analyses were performed to assess the association between LBP and NP, and the effect of preceding LBP on the subsequent onset of NP, according to the frequency of LBP. LBP was significantly associated with NP, and the association was stronger with increased frequency of LBP. Adjusted odds ratios (95% confidence intervals) were 2.40 (1.71-3.37) for "1", 3.99 (2.82-5.66) for "2", and 6.08 (4.40-8.41) for "≥ 3" in frequency when the absence of LBP was used as a reference (p for trend < 0.001). Furthermore, preceding LBP was significantly associated with subsequent onset of NP, and the effect was stronger with increased frequency of LBP. Adjusted odds ratios (95% confidence intervals) were 2.44 (1.62-3.68) for "1" and 2.68 (1.77-4.05) for "≥ 2" in frequency when the absence of LBP was used as a reference (p for trend < 0.001). LBP is associated with NP in a dose-dependent manner. The association between LBP and NP should be considered to effectively treat these pains.

How Long Would You Like to Live? A 25-year Prospective Observation of the Association Between Desired Longevity and Mortality

BACKGROUND

Desired longevity represents how strongly people esteem possible extensions of their own lifetime. The association between desired longevity and mortality risk has been reported in only one prospective study, which examined a small sample of older participants. We aimed to examine the hypothesis that desired longevity at middle-age predicted long-term survival.

METHODS

In the prospective cohort study, residents aged 40-64 years were asked how long they would like to live and asked to choose one from three options: longer than, as long as, or shorter than the life expectancy. We used Cox proportional hazards model to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality according to the three groups for desired longevity, treating the "longer than" group as the reference. We conducted mediation analysis to investigate the mechanism for the association between desired longevity and mortality.

RESULTS

We recruited 39,902 residents to the study. Risk of all-cause mortality was significantly higher in the "shorter than" group (HR 1.12; 95% CI, 1.04-1.21). The association was independent of sex, age, marital status, education, medical history, and health status. Regarding cause of death, mortality risk of cancer (HR 1.14; 95% CI, 1.00-1.29) and suicide (HR 2.15; 95% CI, 1.37-3.38) were also higher in the "shorter than" group. The unhealthy lifestyle mediated this association with all-cause mortality by 30.4%.

CONCLUSION

Shorter desired longevity was significantly associated with an increased risk of all-cause mortality, and mortality from cancer and suicide. Lifestyle behaviors particularly mediated this association.

Reproductive Factors and Endometrial Cancer Risk Among Women

Importance

Despite evidence of an association between reproductive factors and endometrial cancer risk, prospective studies have been conducted mainly in non-Asian countries.

Objective

To assess the association between reproductive factors, such as number of deliveries, age at menarche, or menopause, and endometrial cancer risk.

Design, Setting, and Participants

This cohort study used pooled individual data from 13 prospective cohort studies conducted between 1963 and 2014 in the Asia Cohort Consortium. Participants were Asian women. Data analysis was conducted from September 2019 to April 2023.

Exposures

Reproductive factors were assessed using a questionnaire in each cohort.

Main Outcomes and Measures

The main outcome was time to incidence of endometrial cancer. A Cox proportional hazards model was used to calculate hazard ratios (HRs) and 95% CIs.

Results

A total of 1005 endometrial cancer cases were detected among 332 625 women (mean [SD] age, 54.3 [10.4] years) during a mean (SD) of 16.5 (6.4) years of follow-up. Increasing number of deliveries was associated with a decreased endometrial cancer risk in a dose-response manner (≥5 deliveries vs nulliparous [reference]: HR, 0.37; 95% CI, 0.26-0.53; P for trend < .001). Compared with menarche at younger than 13 years, menarche at 17 years or older had an HR of 0.64 (95% CI, 0.48-0.86; P for trend < .001). Late menopause (age ≥55 years) showed an HR of 2.84 (95% CI, 1.78-4.55; P for trend < .001) compared with the youngest age category for menopause (<45 years). Age at first delivery, hormone therapy, and breastfeeding were not associated with endometrial cancer risk.

Conclusions and Relevance

This large pooled study of individual participant data found that late menarche, early menopause, and a higher number of deliveries were significantly associated with a lower risk of endometrial cancer. These convincing results from Asian prospective studies add to the growing body of evidence for the association between reproductive factors and endometrial cancer.

Seaweed consumption and the risk of prostate cancer: the Miyagi cohort study

Some laboratory studies have shown that fucoidan, which is contained in seaweed extract, has inhibitory effects on the invasion and angiogenesis of tumor cells; however, the association between seaweed consumption and prostate cancer incidence remains unclear. The purpose of the present study was to examine the association between seaweed consumption and the risk of prostate cancer incidence in the Japanese population. Data from 19 311 men in the Miyagi Cohort Study who were 40-64 years old at baseline in 1990 were examined. Seaweed consumption was assessed at baseline using a self-administered food frequency questionnaire. The participants were divided into three categories based on seaweed consumption at baseline. During 24.5 years of follow-up, we identified 815 incident cases of prostate cancer. Multivariate analysis showed that seaweed consumption was not associated with prostate cancer incidence. The multivariate hazard ratios and 95% confidence intervals for prostate cancer incidence in the highest tertile versus the other tertiles were 0.76 (0.60-0.96) and 0.78 (0.61-0.99) ( P -trend = 0.15). Furthermore, the null association was independent of whether their clinical stage was localized or advanced. In this population-based prospective cohort study conducted in Japan, we found no significant association between seaweed consumption and the incidence of prostate cancer.

The Association of Lung Function and Carotid Intima-Media Thickness in a Japanese Population: The Tohoku Medical Megabank Community-Based Cohort Study

AIM

Impaired lung function is associated with atherosclerotic vascular events. Carotid intima-media thickness (cIMT) is a marker for subclinical atherosclerosis. However, few studies have examined the association between lung function and cIMT among never smokers or individuals stratified by age. We investigated the association between lung function and cIMT in the Japanese population.

METHODS

We conducted a cross-sectional study of 3,716 men and 8,765 women aged 20 years or older living in Miyagi Prefecture, Japan. Lung function was evaluated using forced expiratory volume at 1 s (FEV1) and forced vital capacity (FVC) was measured using spirometry. The maximum common carotid artery was measured using high-resolution B-mode ultrasound. An analysis of covariance was used to assess associations between lung function and cIMT and adjusted for potential confounders. A linear trend test was conducted by scoring the categories from 1 (lowest) to 4 (highest) and entering the score as a continuous term in the regression model.

RESULTS

After adjusting for potential confounders including passive smoking, lower FEV1 and FVC were associated with higher cIMT in both men and women (P＜0.001 for linear trend). This association was confirmed even when we restricted our study to never smokers. Furthermore, even when we stratified by age, an inverse association between lung function and cIMT was confirmed in middle-aged (40-64 years) and elderly participants (65-74 years).

CONCLUSIONS

Lower lung function was associated with higher cIMT in the Japanese population independent of age and smoking. Assessment of atherosclerosis or lung function may be required for individuals with lower lung function or atherosclerosis.

Effect of the decreased frequency of going out on the association between anxiety and sleep disorder during the COVID-19 pandemic: a mediation analysis

PURPOSE

The objective of the present study was to examine the relationship between anxiety and sleep disorder during the COVID-19 pandemic and to evaluate whether sleep disorder is mediated by the decreased frequency of going out.

METHODS

The data of a total of 1976 residents aged 18 years and over who had responded to a self-reported questionnaires at a health survey in 2020 were analyzed. The subjects were divided into four groups based on their response to the questionnaire on anxiety about the COVID-19 pandemic. Sleep disorder was measured using the Athens Insomnia Scale (AIS). A cross-sectional analysis was performed to examine the association between anxiety about the COVID-19 pandemic and AIS scores. Mediation analysis was used to calculate the association between anxiety and AIS scores during the COVID-19 pandemic, with decreased frequency of going out as a potential mediating variable.

RESULTS

In the cross-sectional study, the level of anxiety about the COVID-19 pandemic was significantly associated with the AIS score (p < 0.001). On mediation analysis, the direct effect of the relationship showed that anxiety positively influenced AIS scores (β = 0.283, p < 0.01). The indirect effect of the relationship showed that the decreased frequency of going out positively mediated the relationship between anxiety and AIS scores (β = 0.342, p < 0.05). The decreased frequency of going out accounted for almost 10% of the AIS score.

CONCLUSION

The present study found that anxiety about the COVID-19 pandemic was significantly associated with sleep disorder, with the decreased frequency of going out mediating this association.

Evacuation at Home Delayed the First Medical Intervention in Minamisanriku Town after the 2011 Great East Japan Earthquake

INTRODUCTION

In Japan, evacuation at home is expected to increase in the future as a post-disaster evacuation type due to the pandemic, aging, and diverse disabilities of the population. However, more disaster-related indirect deaths occurred in homes than in evacuation centers after the 2011 Great East Japan Earthquake (GEJE). The health risks faced by evacuees at home have not been adequately discussed.

STUDY OBJECTIVE

This study aimed to clarify the gap in disaster health management for evacuees at home compared to the evacuees at the evacuation centers in Minamisanriku Town, which lost all health care facilities after the 2011 GEJE.

METHODS

This was a retrospective cross-sectional and quasi-experimental study based on the anonymized disaster medical records (DMRs) of patients from March 11 through April 10, 2011, that compared the evacuation-at-home and evacuation-center groups focusing on the day of the first medical intervention after the onset. Multivariable Cox regression analysis and propensity score (PS)-matching analysis were performed to identify the risk factors and causal relationship between the evacuation type and the delay of medical intervention.

RESULTS

Of the 2,838 eligible patients, 460 and 2,378 were in the evacuation-at-home and evacuation-center groups, respectively. In the month after the onset, the evacuation-at-home group had significantly lower rates of respiratory and mental health diseases than the evacuation-center group. However, the mean time to the first medical intervention was significantly delayed in the evacuation-at-home group (19.3 [SD = 6.1] days) compared to that in the evacuation-center group (14.1 [SD = 6.3] days); P <.001). In the multivariable Cox regression analysis, the hazard ratio (HR) of delayed medical intervention for evacuation-at-home was 2.31 with a 95% confident interval of 2.07-2.59. The PS-matching analysis of the adjusted 459 patients in each group confirmed that evacuation at home was significantly associated with delays in the first medical intervention (P <.001).

CONCLUSION

This study suggested, for the first time, the causal relationship between evacuation at home and delay in the first medical intervention by PS-matching analysis. Although evacuation at home had several advantages in reducing the frequencies of some diseases, the delay in medical intervention could exacerbate the symptoms and be a cause of indirect death. As more evacuees are likely to remain in their homes in the future, this study recommends earlier surveillance and health care provision to the home evacuees.

Psychological distress in later life and incident dementia: The Ohsaki Cohort 2006 Study

BACKGROUND

The role of reverse causation in the association between psychological distress and incident dementia remains unclear. We investigated whether psychological distress is a risk factor for, or prodromal symptom of, dementia.

METHODS

A longitudinal analysis of psychological distress with incident dementia was conducted among 12,076 Japanese individuals (age ≥65 years) followed for 5.7 years. Psychological distress was measured using the Kessler 6-item psychological distress scale (0-24 points) at baseline, with participants categorized into four psychological distress groups: no (0-4), mild (5-9), moderate (10-12), and serious (13-24). Dementia cases were retrieved from the public Long-term Care Insurance database. Cox proportional hazards model was used to estimate the multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (95%CIs) for incident dementia. Stratified analysis was conducted by cognitive function (higher or lower) at baseline.

RESULTS

During 60,240 person-years of follow-up, 997 individuals developed dementia. A dose-response association was found between psychological distress and dementia; however, the stratified analysis indicated that this association depended on cognitive function at baseline. Among those with higher cognitive function at baseline, a significantly elevated dementia risk was observed only for serious psychological distress (HR: 2.04, 95%CI: 1.24-3.36). Among those with lower cognitive function, both moderate (HR: 1.30, 95%CI: 1.00-1.68) and serious (HR: 1.79, 95%CI: 1.37-2.34) psychological distress showed an increased dementia risk.

CONCLUSION

The association between late-life psychological distress and incident dementia is partly explained by reserve causation, whereby mild and moderate distress could be a prodromal symptom of dementia.

Body mass index and esophageal and gastric cancer: a pooled analysis of ten population-based cohort studies in Japan

The effect of body mass index (BMI) on esophageal and gastric carcinogenesis might be heterogeneous, depending on subtype or subsite. However, findings from prospective evaluations of BMI associated with these cancers among Asian populations have been inconsistent and limited, especially for esophageal adenocarcinoma and gastric cardia cancer. We performed a pooled analysis of ten population-based cohort studies to examine this association in 394,247 Japanese individuals. We used Cox proportional hazards regression to estimate study-specific hazard ratios (HRs) and 95% confidence intervals (CIs), then pooled these estimates to calculate summary HRs with a random effects model. During 5,750,107 person-years of follow-up, 1,569 esophageal cancer (1,038 squamous cell carcinoma and 86 adenocarcinoma) and 11,095 gastric (728 cardia and 5,620 non-cardia) cancer incident cases were identified. An inverse association was observed between BMI and esophageal squamous cell carcinoma (HR per 5-kg/m² increase, 0.57; 95% CI, 0.50-0.65), whereas a positive association was seen in gastric cardia cancer (HR, 1.15; 95% CI, 1.00-1.32). A non-significant and significant positive association for overweight or obese (BMI ≥25 kg/m² ) relative to BMI <25 kg/m² was observed with esophageal adenocarcinoma (HR, 1.32; 95% CI, 0.80-2.17) and gastric cardia cancer (HR, 1.24; 95% CI, 1.05-1.46), respectively. No clear association with BMI was found for gastric non-cardia cancer. This prospective study - the largest in an Asian country - provides a comprehensive quantitative estimate of the association of BMI with upper gastrointestinal cancer, and confirms the subtype- or subsite-specific carcinogenic impact of BMI in a Japanese population.

Associations between the Combined Fat Mass Index and Fat-Free Mass Index with Carotid Intima-Media Thickness in a Japanese Population: The Tohoku Medical Megabank Community-Based Cohort Study

AIM

Although many epidemiological studies have shown that obesity assessed by body mass index is associated with carotid intima-media thickness (cIMT), few studies have evaluated fat-free mass, which is a component of body composition. We investigated the associations between the combined fat mass index (FMI) and fat-free mass index (FFMI) with cIMT.

METHODS

We conducted a cross-sectional study of 3,873 men and 9,112 women aged 20 years or older who lived in Miyagi prefecture, Japan. The FMI and FFMI were calculated as fat mass and fat-free mass divided by height squared, respectively. The indices were classified into sex-specific quartiles and were combined into 16 groups. The maximum common carotid artery was measured using high-resolution B-mode ultrasound. An analysis of covariance was used to assess associations between the combined FMI and FFMI with cIMT adjusted for age and smoking status. The linear trend test was conducted by stratifying the FMI and FFMI, scoring the categories from 1 (lowest) to 4 (highest), and entering the number as a continuous term in the regression model.

RESULTS

In multivariable models, a higher FMI was not related to higher cIMT in men and women in most FFMI subgroups. Conversely, a higher FFMI was related to higher cIMT in all FMI subgroups (p＜0.001 for linear trend).

CONCLUSIONS

FMI was not associated with cIMT in most FFMI subgroups. Conversely, FFMI was positively associated with cIMT independently of FMI.

Association between lung function and hypertension and home hypertension in a Japanese population: the Tohoku Medical Megabank Community-Based Cohort Study

BACKGROUND

Although several studies have shown an inverse association between lung function and hypertension, few studies have examined the association between lung function and hypertension among never-smokers, and no study has investigated the association between lung function and home hypertension. We investigated the associations between lung function and hypertension in a Japanese population.

INDIVIDUALS AND METHODS

We conducted a cross-sectional study of 3728 men and 8795 women aged 20 years or older living in Miyagi Prefecture, Japan. Lung function was assessed using forced expiratory volume at 1 s (FEV 1 ) and forced vital capacity (FVC), measured by spirometry. Hypertension was defined as a casual blood pressure at least 140/90 mmHg and/or self-reported treatment for hypertension. Home hypertension was defined as morning home blood pressure at least 135/85 mmHg and/or self-reported treatment for hypertension. Multivariate logistic regression models adjusted for potential confounders were used to assess the association between lung function and hypertension.

RESULTS

The mean ages (±SD) of men and women were 60.1 (±14.0) years and 56.2 (±13.4) years, respectively, and 1994 (53.5%) men and 2992 (34.0%) women had hypertension. In the multivariable models, FEV 1 and FVC were inversely associated with hypertension. Inverse associations between lung function and hypertension were observed even among never-smokers. Furthermore, reduced lung function was associated with higher prevalence of home hypertension in men and women.

CONCLUSION

Reduced lung function was associated with higher prevalence of hypertension, independent of smoking status. Assessment of the lung function or blood pressure may be required in individuals with reduced lung function or hypertension.

Association between personality and the risk of ischemic heart disease mortality before and after the Great East Japan Earthquake: Data from the Miyagi Cohort Study

BACKGROUND

The purpose of the present study was to investigate the association between personality and the risk of IHD mortality among Great East Japan Earthquake (GEJE) survivors, and to investigate whether personality traits affected the increase in IHD mortality observed after the GEJE.

METHODS

We analyzed data for 29,065 men and women in the Miyagi Cohort Study who were 40-64 years old at baseline. We divided the participants into quartiles based on scores for each of the four personality subscales (extraversion, neuroticism, psychoticism, and lie), using the Japanese version of the Eysenck Personality Questionnaire-Revised Short Form. We divided the eight years before and after the GEJE event (11 March 2011) into two period, and examined the relationship between personality traits and the risk of IHD mortality. Cox proportional hazards analysis was used to estimate the multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of IHD mortality according to each personality subscale category.

RESULTS

In the four years before the GEJE, neuroticism was significantly associated with an increased risk of IHD mortality. Compared with the lowest category for neuroticism, the multivariate-adjusted HR (95% CI) for IHD mortality in the highest category was 2.19 (1.03-4.67) (p-trend = 0.12). In contrast, no statistically significant association between neuroticism and IHD mortality was observed in the four years after the GEJE.

CONCLUSION

This finding suggests that the observed increase in IHD mortality after the GEJE can be attributed to risk factors other than personality.

Low back pain is associated with sleep disturbance: a 3-year longitudinal study after the Great East Japan Earthquake

BACKGROUND

Low back pain and sleep disturbance are common health problems worldwide which are also commonly observed among people after natural disasters. These symptoms are well known to coexist, and recent reports have indicated that sleep disturbance is a risk factor for low back pain. However, the influence of low back pain on sleep disturbance has rarely been assessed; therefore, this study aimed to clarify the association of low back pain with sleep disturbance, especially focusing on the frequency of low back pain, using 3-year cohort data after the Great East Japan Earthquake.

METHODS

This study used the data obtained from people living in the disaster-affected areas after the Great East Japan Earthquake (n = 2,097). Low back pain and sleep disturbance were assessed at 4, 5, 6, and 7 years after the disaster. The frequency of low back pain was defined as the number of low back pain episodes at and before the evaluation time point and categorized into five groups such as absence, 1, 2, 3, and 4 at the fourth time point and four groups such as absence, 1, 2, and 3 at the third time point. Multivariate logistic regression analyses were conducted to assess the association of low back pain with sleep disturbance.

RESULTS

Low back pain was significantly associated with sleep disturbance, and the association was stronger in participants with more frequent low back pain (adjusted odds ratios [95% confidence intervals],1.46 [1.10-1.95] in "1"; 2.02 [1.49-2.74] in "2"; 2.38 [1.67-3.40] in "3"; and 4.08 [2.74-6.06] in "4" in the frequency of low back pain) (P for trend < 0.001). Furthermore, antecedent low back pain was significantly associated with new-onset sleep disturbance, and the association was robust in more frequent low back pain (adjusted odds ratios [95% confidence intervals],1.60 [1.05-2.44] in "1"; 1.96 [1.20-3.21] in "2"; and 2.17 [1.14-4.14] in "3" in the frequency of low back pain) (P for trend = 0.007).

CONCLUSION

Our study showed that low back pain is strongly associated with sleep disturbance. Attention should be paid to low back pain to prevent and treat sleep disturbance, especially focusing on chronicity of low back pain.

Association between low back pain and functional disability in the elderly people: a 4-year longitudinal study after the great East Japan earthquake

BACKGROUND

Functional disability is a major health issue in an aging population. Low back pain (LBP) is a common health concern that can lead to functional disability in the elderly; nonetheless, their association has not yet been clarified. This study aimed to examine the association between LBP and functional disability in the elderly, with a focus on its dose-dependent effects.

METHODS

This study used the 4-year longitudinal data of people living in disaster-affected areas after the Great East Japan Earthquake (aged ≧65, n = 914). LBP and physical function were assessed at 2, 4, and 6 years after the disaster. Multivariate logistic regression analyses were performed to assess the association between LBP and low physical function, as well as the effect of preceding LBP on the onset of low physical function.

RESULTS

LBP was significantly associated with low physical function, and the association became stronger as the duration of LBP increased. Adjusted odds ratios (95% confidence intervals) were 1.27 (0.79-2.06) in "< 2 years," 1.95 (1.01-3.77) in "≥2 years and <4 years," and 2.34 (1.35-4.06) in "≥4 years" (p for trend = 0.009). Additionally, preceding LBP was significantly associated with the onset of low physical function, and the effect became prominent as the duration of LBP increased. Adjusted odds ratios (95% confidence intervals) were 2.28 (1.19-4.37) in "< 2 years" and 2.82 (1.35-5.90) in "≥2 years" (p for trend = 0.003).

CONCLUSIONS

LBP is associated with physical disability among the elderly in a dose-dependent manner. Therefore, prevention and treatment of LBP are important for preventing functional disability.

Association between the number of remaining teeth and disability-free life expectancy, and the impact of oral self-care in older Japanese adults: a prospective cohort study

Background

Tooth loss has been reportedly associated with shorter disability-free life expectancy (DFLE). However, no study has explored whether oral self-care offsets reduction in DFLE. The present study aimed to assess the association between oral self-care and DFLE in older individuals with tooth loss.

Methods

Data on the 13-year follow-up from a cohort study of 14,206 older Japanese adults aged ≥ 65 years in 2006 were analyzed. Information on the number of remaining teeth was collected using a questionnaire, and the participants were then categorized into three groups (0–9, 10–19, and ≥ 20 teeth). Additionally, “0–9” and “10–19” groups were divided into two subgroups based on whether they practiced oral self-care. DFLE was defined as the average number of years a person could expect to live without disability, and was calculated by the multistate life table method based on a Markov model.

Results

DFLE (95% confidence interval) was 19.0 years (18.7–19.4) for 0–9 teeth, 20.1 (19.7–20.5) for 10–19 teeth, and 21.6 (21.2–21.9) for ≥ 20 teeth for men. For women, DFLE was 22.6 (22.3–22.9), 23.5 (23.1–23.8), and 24.7 (24.3–25.1), respectively. Practicing oral self-care was associated with longer DFLE, by 1.6–1.9 years with brushing ≥ 2 times a day in people with 0–9 and 10–19 teeth, and by 3.0–3.1 years with the use of dentures in those with 0–9 teeth.

Conclusions

Practicing oral self-care is associated with an increase in DFLE in older people with tooth loss.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03541-2.

Changes in time spent walking and disability-free life expectancy in Japanese older people: The Ohsaki Cohort 2006 Study

An increase in time spent walking is significantly associated with lower risks of mortality and disability. This study aimed to investigate the association between changes in time spent walking and disability-free life expectancy (DFLE) in community-dwelling older people. Thirteen-year follow-up data from a cohort study of 7105 Japanese older adults (age ≥ 65 years) in 2006 were analyzed. Information on time spent walking was collected using questionnaires at two time points (1994 and 2006). Based on this information, the participants were categorized into four groups according to changes in time spent walking: remained inactive, became inactive, became active, and remained active. DFLE was defined as the average number of years a person could expect to live without disability. The multistate life table method using a Markov model was used to calculate DFLE. Of those who were inactive in 1994, DFLE of those who became active in 2006 (20.30 years in men; 24.06 years in women) was longer by about 2 years than of those who remained inactive (17.96 years in men; 21.87 years in women), and it was as long as those who remained active (20.34 years in men; 24.16 years in women). The 2-year difference in DFLE did not change after the participants were stratified by body mass index, motor function, cognitive function, and history of diseases. Increase in time spent walking is associated with longer DFLE in Japanese older people. Encouraging simple physical activity such as walking at the population level could increase life-years lived in good health.

The associations of the national health and productivity management program with corporate profits in Japan

Objectives

Using a dataset from a survey on national health and productivity management, we identified health and productivity factors associated with organizational profitability.

Methods

The Ministry of Economy, Trade and Industry conducted an annual survey on Health and Productivity Management between 2014 and 2021. We assessed the associations of organizational health and productivity management using survey questions collected in 2017 and 2018, and the rate of change in profits from 2017 and 2018 to 2020. We identified factors associated with organizational profitability using eXtreme Gradient Boosting, and calculated SHapley Additive exPlanation (SHAP) values for each factor.

Results

Among 1,593 companies (n=4,359,834 employees), the mean age for employees at baseline was 40.3 years and the proportion of women was 25.8%. The confusion matrix for evaluating model performance had accuracy of 0.997, precision of 0.993, recall of 0.997; and area under the precision-recall curve of 0.999. The most important factors related to an increase in corporate profits were the percentage of current smokers (SHAP value 0.121), per-employee cost for health services (0.084) and medical services (0.050); the percentage of full-time employees working in sales departments (0.074), distribution or customer service departments (0.054); the percentage of employees who sleep well (0.055); and the percentage of employees who have a habit of regular exercise within a company (0.043).

Conclusion

The lifestyle health risk factors of employees and organizations' management systems were associated with organizational profitability. Lifestyle medicine professionals may demonstrate a significant return on investment by creating a healthier and more productive.

High Mortality in an Older Japanese Population with Low Forced Vital Capacity and Gender-Dependent Potential Impact of Muscle Strength: Longitudinal Cohort Study

Generally, weak muscle power is associated with high mortality. We aimed to evaluate the unknown association between % predicted value forced vital capacity (FVC% predicted) and mortality in asymptomatic older people, and the impact of muscle power on this association. We analyzed the Tsurugaya cohort that enrolled Japanese people aged ≥70 for 15 years with Cox proportional hazards model. Exposure variables were FVC% predicted and leg power. The outcome was all-cause mortality. The subjects were divided into quartiles by FVC% predicted or leg power, or into two groups by 80% for FVC% predicted or by the strongest 25% for leg power. Across 985 subjects, 262 died. The males with lower FVC% predicted exhibited higher mortality risks. The hazard ratio (HR) was 2.03 (95% CI 1.30−3.18) at the lowest relative to the highest groups. The addition of leg power reduced the HR to 1.78 (95% CI 1.12−2.80). In females, FVC% predicted under 80% was a risk factor and the HR was 1.67 (95% CI 1.05−2.64) without the effect of leg power. In FVC% predicted <80% males HRs were 2.44 (95% CI 1.48−4.02) in weak and 1.38 (95% CI 0.52−3.64) in strong leg power males, relative to ≥80% and strong leg power males. Low FVC% predicted was associated with high mortality with potential unfavorable effects of weak leg power in males.

Association between Body Mass Index and Risk of Gastric Cancer by Anatomic and Histologic Subtypes in Over 500,000 East and Southeast Asian Cohort Participants

BACKGROUND

This study was performed to investigate the association between body mass index (BMI) and gastric cancer in East and Southeast Asia where most of gastric cancer is non-cardia gastric cancer.

METHODS

On the basis of 8,997 gastric cancer cases among the Asia Cohort Consortium participants from China, Japan, Korea, and Singapore (N = 538,835), we assessed gastric cancer risk according to BMI by calculating hazard ratios (HR) and 95% confidence intervals (CI) using the Cox proportional hazard regression model.

RESULTS

A U-shaped associations between BMI and gastric cancer risk were observed. Gastric cancer risks in underweight group (&lt;18.5 kg/m2) and in obesity group (≥27.5 kg/m2) were higher than reference BMI group (23-24.9 kg/m2; HR, 1.15; 95% CI, 1.05-1.25 for underweight; HR, 1.12; 95% CI, 1.03-1.22 for obesity, respectively). The associations of underweight and obesity with gastric cancer risk were consistent in the analyses for non-cardia gastric cancer, intestinal-type gastric cancer, and late-onset gastric cancer. No significant association of underweight and obesity with the risk of cardia gastric cancer, diffuse-type gastric cancer, and early-onset gastric cancer was observed. In addition, we found that the U-shaped association between BMI and gastric cancer risk remained in nonsmokers, while only underweight was related to increased gastric cancer risk in smokers.

CONCLUSIONS

BMI has a U-shaped association with gastric cancer risk in East and Southeast Asian population, especially for the non-cardia gastric cancer, intestinal-type gastric cancer, and late-onset gastric cancer.

IMPACT

Future studies with consideration of anatomic location and histology of gastric cancer are needed to establish the association of underweight as well as obesity with gastric cancer risk.

How does social support modify the association between psychological distress and risk of suicide death?

BACKGROUND

Social support (SS) has been reported as a factor preventing suicide death, but whether this association is independent of mental status is unclear. The present study examined the effect modification of SS on the association between psychological distress status and risk of suicide death.

METHODS

Follow-up data for 43,015 subjects participating in a prospective cohort study were analyzed. At baseline, the subjects were asked about SS and mental status with the Kessler six-item Distress (K6) Scale. A Cox model was used to estimate the multivariate-adjusted hazard ratios (HRs) of suicide death according to two levels of psychological distress (K6 ≤ 4, K6 ≥ 5). The HRs in each SS subtype (emotional and instrumental) were also calculated.

RESULTS

There was a significant association between SS and a lower risk of suicide death in the stratum of K6 ≥ 5, with an HR of 0.58 (95% confidence interval, 0.35-0.96). On the other hand, the association with the K6 ≤ 4 strata was not significant.

CONCLUSION

SS appears to be associated with a lower risk of suicide death only among participants with moderate or severe psychological distress. These results imply that early detection of psychological distress and provision of SS is important for preventing suicide death.

Time spent walking and disability-free survival in older Japanese: The Ohsaki Cohort 2006 Study

The extent to which long disability-free survival (DFS) time can be extended according to the amount of time spent walking has not been investigated. The aim of this study was to examine the association between time spent walking per day and DFS time in older adults. We conducted a cohort study of 14 342 disability-free individuals (aged ≥ 65 years) living in Ohsaki City, Japan. The amount of time spent walking per day (<0.5 h, 0.5-1 h, ≥1 h) by each individual in 2006 was assessed by a self-reported questionnaire. Data on 11-year incident functional disability were retrieved from the public Long-Term Care Insurance database. After estimating the multivariable-adjusted hazard ratios (HRs) of the composite outcome (incident functional disability or death), the multivariable-adjusted 50th percentile differences (50th PDs; difference in the period until the first 50% of the composite outcome occurred) were estimated according to time spent walking. Among 114 764 person-years, the composite outcome occurred in 7761 persons (67.6 per 1000 person-years). The HRs (95% confidence intervals) of the composite outcome were 1.00 (reference) for <0.5 h, 0.84 (0.79, 0.88) for 0.5-1 h, and 0.78 (0.74, 0.83) for ≥1 h (p-trend < 0.001). The 50th PDs (95% confidence intervals) of DFS time were 238 (155, 322) days longer for 0.5-1 h and 360 (265, 454) days longer for ≥1 h, in comparison with <0.5 h. The results suggest that longer time spent walking per day contributes to longer DFS time.

Relationship between the housing coldness/warmth evaluation by CASBEE Housing Health Checklist and psychological distress based on TMM Community-Based Cohort Study: a cross-sectional analysis

OBJECTIVES

Previous studies have reported the relationship between housing environment and health, although due to cost and effort, it was difficult to conduct housing condition surveys on a large scale. The CASBEE Housing Health Checklist (the Checklist) made it possible to easily evaluate the housing condition from the resident's perspective. This study examined the relationship between housing coldness/warmth evaluation using the Checklist and psychological distress in a large-scale general Japanese population.

STUDY DESIGN

A cross-sectional study.

METHODS

We analysed data from 29,380 people aged ≥20 years who lived in Miyagi Prefecture, Japan. As an assessment of housing coldness/warmth, we used the Checklist. We classified participants' total scores on the Checklist related to coldness/warmth into quartiles. The Kessler 6 scale was used as an indicator of psychological distress. Multivariable logistic regression models were used to estimate the adjusted odds ratio (OR) and 95% confidence intervals (CIs). Adjusted OR and P-values for linear trends were calculated using the quartiles of the Checklists' score.

RESULTS

Among participants in Q1 (i.e., poorer subjective house condition), the percentage of people with psychological distress was high. Compared to the highest quartile, Q1 showed poorer evaluation of housing coldness/warmth, and higher OR for psychological distress. The OR (95% CI) of psychological distress for Q3, Q2, and Q1 compared with Q4 were 1.93 (1.74-2.14), 2.82 (2.55-3.12), and 5.78 (5.25-6.35), respectively.

CONCLUSIONS

Housing coldness/warmth evaluation was significantly related to psychological distress. This finding suggests that maintaining a comfortable thermal environment at home could be important for residents' mental health.

Sleep duration and risk of cancer incidence and mortality: a pooled analysis of six population-based cohorts in Japan

Sleep duration is emerging as an important modifiable risk factor for morbidity and mortality. We assessed the association between sleep duration and cancer incidence and mortality among Japanese adults using data from six population-based cohorts with 271 694 participants. During a total follow-up period of about 5.9 million person-years, we identified 40 751 incident cancer cases and 18 323 cancer deaths. We computed study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazards regression models and pooled the estimates using random-effects meta-analysis. Sleep duration of ≥ 10 h (vs. 7 h) was associated with increased risk of cancer incidence among women (HR 1.19, 95% CI 1.02-1.38), but not men, and increased risk of cancer mortality among men (HR 1.18, 95% CI 1.00-1.39) and women (HR 1.44, 95% CI 1.20-1.73). Sleep duration of ≤ 5 h (vs. 7 h) was not associated with cancer incidence and mortality. However, among post-menopausal women, sleep durations of both ≤ 5 h and ≥ 10 h (vs. 7 h) were associated with an increased risk of cancer mortality. Among Japanese adults, sleep duration of ≥ 10 h is associated with increased risk of cancer incidence and mortality among women and cancer mortality among men. This article is protected by copyright. All rights reserved.

Association between cognitive social capital and all-cause mortality in Great East Japan Earthquake survivors: a prospective cohort study

OBJECTIVES

Cognitive social capital (SC), such as attitude, trust, or norms, may help improve resilience among survivors, thus improving their health. However, the association between cognitive SC and the risk of all-cause mortality among survivors after the natural disaster has never been investigated. The purpose of the present study is to investigate the association between cognitive SC and the risk of all-cause mortality among survivors of the Great East Japan Earthquake (GEJE).

STUDY DESIGN

Prospective cohort study.

METHODS

We conducted a health survey on 1654 residents aged ≥18 years who lived in two areas affected by the GEJE. One year after the GEJE, between June and August 2012, cognitive SC (helping each other, trust, greeting, and solving problems together) was assessed using a self-administrated questionnaire. We divided the subjects into two groups based on response to questionnaire: "high" or "low." We obtained information on death and emigration from the Residential Registration Record and followed up on the participants from June 2012 to November 2020. The Cox proportional hazards regression analysis was used for estimating the multivariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of all-cause mortality according to each cognitive SC indicator.

RESULTS

During the 8.5 years of follow-up, 213 subjects died (12.9%). For greeting, compared with subjects who were "high," subjects who were "low" were significantly associated with the risk of all-cause mortality (HR: 2.92, 95% CI: 1.19-7.17). No statistically significant association was observed for helping each other, trust, and solving problems together.

CONCLUSION

Our findings suggest that perception of greeting may be associated with the risk of all-cause mortality in survivors after natural disasters.

Sleep disturbance is associated with neck pain: a 3-year longitudinal study after the Great East Japan Earthquake

Background

Neck pain is a common health problem in the general population as well as in people after natural disasters. Sleep disturbances are gaining attention as risk factors for musculoskeletal pain; however, the association between sleep disturbance and neck pain has not been clarified. The present study aimed to clarify the association between sleep disturbance and neck pain, especially focusing on the effect of the duration of sleep disturbance, after the Great East Japan Earthquake.

Methods

This study used 3-year longitudinal data obtained from individuals (n = 2,059) living in disaster-affected areas after the Great East Japan Earthquake. Sleep disturbance and neck pain were investigated at 4, 5, 6, and 7 years after the disaster. Multivariate logistic regression analyses were used for the assessment.

Results

Sleep disturbance was significantly associated with neck pain, and the association was stronger as the duration of sleep disturbance increased (adjusted odds ratios [95% confidence intervals]: 1.84 [1.23–2.75] for “ < 1 year”; 2.41 [1.53–3.81] for “ ≥ 1 year and < 2 years”; 2.80 [2.09–3.76] for “ ≥ 2 years”). Furthermore, preceding sleep disturbance was significantly associated with the onset of neck pain, and the association was stronger as the duration of sleep disturbance increased (adjusted odds ratios [95% confidence intervals]: 1.86 [1.08–3.20] for “ < 1 year”; 2.39 [1.22–4.70] for “ ≥ 1 year and < 2 years”; 3.00 [1.94–4.65] for “ ≥ 2 years”).

Conclusions

Sleep disturbance is associated with neck pain, and long-lasting sleep disturbance strengthens the association. Clinicians should consider this association to effectively treat patients with neck pain, especially those affected by natural disasters.

Japanese Diet and Mortality, Disability, and Dementia: Evidence from the Ohsaki Cohort Study

The Japanese dietary pattern has long been discussed as one of the factors behind the longevity of Japanese people. However, the health benefits of the Japanese dietary pattern have not been fully elucidated. We published the first report in the world regarding the relation between the Japanese dietary pattern and cardiovascular disease mortality in 2007 using cohort studies including Japanese residents of Ohsaki City, Miyagi Prefecture, Japan. Since then, we have developed the Japanese Diet Index (JDI) that was based on previous findings to assess the degree of the Japanese dietary pattern and to advance the evidence on the health effects of the Japanese dietary pattern. So far, we have explored the associations between the JDI score (in quartiles) and various outcomes. For all-cause mortality, in comparison to Q1 (the lowest), the multivariable hazard ratios (HRs) and 95% confidence intervals (95%CIs) were 0.92 (0.85–1.00) for Q2, 0.91 (0.83–0.99) for Q3, and 0.91 (0.83–0.99) for Q4 (the highest). For functional disability, the multivariable HRs (95%CIs) were 0.94 (0.81–1.09) for Q2, 0.90 (0.77–1.05) for Q3, and 0.79 (0.68–0.92) for Q4. For dementia, the multivariable HRs (95%CIs) were 0.88 (0.74–1.05) for Q2, 0.87 (0.73–1.04) for Q3, 0.79 (0.66–0.95) for Q4. In addition, people with higher adherence to the Japanese dietary pattern also showed decreases in disability and dementia risks. The purpose of this article was to review all six papers, summarize the health effects of the Japanese dietary pattern, and discuss implications for future research.

Association of Marital Status With Total and Cause-Specific Mortality in Asia

IMPORTANCE

Marital status has been shown to be associated with mortality, but evidence in Asian populations is limited.

OBJECTIVE

To examine the association of marital status with total and cause-specific mortality.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included individual participant data from 16 prospective studies in the Asia Cohort Consortium conducted between 1963 and 2015. Asian participants with complete information on marital and vital status were included. Study-specific hazard ratios (HRs) and 95% CIs were estimated using Cox proportional hazards model and then pooled using a random-effects meta-analysis. The analysis began in February 2021 and ended in August 2021.

EXPOSURES

Marital status.

MAIN OUTCOMES AND MEASURES

All-cause and cause-specific mortality.

RESULTS

Of 623 140 participants (326 397 women [52.4%] and 296 743 men [47.6%]; mean [SD] age, 53.7 [10.2] years; mean [SD] follow-up time, 15.5 [6.1] years), 123 264 deaths were ascertained. Compared with married individuals, those who were unmarried had pooled HRs of 1.15 (95% CI, 1.07-1.24) for total mortality, 1.12 (95% CI, 1.03-1.22) for cerebrovascular disease mortality, 1.20 (95% CI, 1.09-1.31) for coronary heart disease mortality, 1.17 (95% CI, 1.07-1.28) for circulatory system diseases mortality, 1.06 (95% CI, 1.01-1.11) for cancer mortality, 1.14 (95% CI, 1.05-1.23) for respiratory diseases mortality, and 1.19 (95% CI, 1.05-1.34) for external causes of death. Positive associations with total mortality were also observed for those who were single (HR, 1.62; 95% CI, 1.41-1.86), separated (HR, 1.35; 95% CI, 1.13-1.61), divorced (HR, 1.38; 95% CI, 1.13-1.69), and widowed (HR, 1.09; 95% CI, 1.04-1.13). In subgroup analyses, the positive association persisted across baseline health conditions, and the risk of death was more pronounced among men or people younger than 65 years.

CONCLUSIONS AND RELEVANCE

This large pooled cohort study of individual participant data provides strong evidence that being unmarried, as well as belonging to the unmarried subcategories, was positively associated with total and cause-specific mortality. Investment of targeted social support services might need to be considered in light of the mortality differences between married and unmarried individuals.

Association between fat mass index, fat-free mass index and hemoglobin A1c in a Japanese population: The Tohoku Medical Megabank Community-based Cohort Study

AIMS/INTRODUCTION

Fat mass and fat-free mass affect glycated hemoglobin A1c (HbA1c) levels and blood glucose levels, respectively. The aim of the present study was to examine the association between the fat mass index and fat-free mass index with HbA1c.

MATERIALS AND METHODS

We carried out a cross-sectional study that included 3,731 men and 9,191 women aged ≥20 years, living in Miyagi Prefecture, Japan, who were not treated for diabetes. The fat mass index and fat-free mass index were calculated as fat mass and fat-free mass divided by the height squared, respectively. The indices were classified into sex-specific quartiles and combined into 16 groups. An analysis of covariance was used to assess associations between the combined fat mass index and fat-free mass index with HbA1c adjusted for potential confounders. The linear trend test was carried out by stratifying the fat mass index and fat-free mass index, entering the number as a continuous term in the regression model.

RESULTS

In multivariable models, a higher fat mass index was related to higher HbA1c levels in men and women in all fat-free mass index subgroups (P < 0.001 for linear trend). When we excluded the participants who had been identified as having diabetes, the fat-free mass index was also related to higher HbA1c levels in most fat mass index subgroups (P < 0.05 for linear trend).

CONCLUSIONS

Fat mass index was positively related to HbA1c levels. The fat-free mass index was also related to HbA1c levels when we excluded participants who had been identified as having have diabetes.

Dairy intake and incident functional disability among older Japanese adults: the Ohsaki Cohort 2006 Study

PURPOSE

Previous studies have investigated the association between dairy intake and functional disability, but their results were inconsistent. Our study aimed to investigate whether dairy intake may protect against incident functional disability among Japanese older adults.

METHODS

We conducted a longitudinal analysis of dairy intake with incident functional disability in a prospective cohort study of 11,911 Japanese individuals aged ≥ 65 years who were followed up for 8.2 years on average. Data on milk, yogurt, and cheese intake were collected using a validated food frequency questionnaire. Total dairy intake was the sum of the daily intake of milk, yogurt, and cheese, which was sex-specifically categorized in quintiles. Data on functional disability were retrieved from the public Long-term Care Insurance database. The Cox proportional hazards model was used to estimate the multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (95%CIs) for incident functional disability.

RESULTS

During 97,234 person-years of follow-up, 4874 persons (40.9%) were ascertained as having functional disability. Our study suggested a null association between total dairy intake and incident risk of functional disability; compared to Q1 (the lowest quintile) group, the multivariable-adjusted HRs (95%CIs) were 0.96 (0.88-1.05) for Q2, 0.93 (0.85-1.02) for Q3, 0.93 (0.85-1.02) for Q4, and 1.01 (0.92-1.10) for Q5 (p-trend = 0.840). We did not find any associations between milk, yogurt, or cheese intake and incident risk of functional disability.

CONCLUSION

We found no evidence showing that dairy intake was associated with functional disability among Japanese older adults.

Body Mass Index and Thyroid Cancer Risk: A Pooled Analysis of Half a Million Men and Women in the Asia Cohort Consortium

Background: Although previous meta-analyses have suggested a dose-response relationship between body mass index (BMI) and thyroid cancer risk, limited evidence has been presented about Asian populations. To assess this association among Asian populations, where underweight is more prevalent than in other regions, a pooled analysis from the Asia Cohort Consortium was conducted. Methods: Baseline height and weight were measured in five cohorts and self-reported in eight cohorts. Thyroid cancer incidence was ascertained by linkage to local cancer registries. Cohorts were treated as a stratum in the Cox proportional hazard model to estimate the pooled hazard ratios (HRs) and corresponding confidence intervals (CIs) from the estimates for each cohort. All analyses were stratified by sex. Results: A total of 538,857 men and women from 13 cohorts from mainland China, Korea, Japan, and Singapore were included in the analysis. During a mean of 15.1 years of follow-up, 1132 thyroid cancer cases were ascertained. Using a BMI of 18.5-22.9 kg/m² as a reference, an elevated risk of thyroid cancer was observed for groups with a BMI between 25 and 29.9 kg/m² (HR: 1.31, [CI: 0.95-1.80]) and a BMI of 30 kg/m² and greater (HR: 1.84, [CI: 0.89-3.81]) in men. Thyroid cancer risk was elevated in women with a BMI of 23-24.9 kg/m² (HR: 1.26, [CI: 1.07-1.48]). The HRs for 5-U increment of BMI showed a linear association among men (HR: 1.25, [CI 1.10-1.55]) but not among women (HR: 1.07, [CI: 0.97-1.18]). Although the overall thyroid cancer risk was lower among underweight men and women, the papillary cancer risk may be elevated among underweight men (HR: 2.24, [CI: 0.75-6.66]). Conclusion: While higher BMI is associated with an elevated risk of thyroid cancer in both men and women, the association of underweight BMI may differ by sex and histological subtype.