Validity of claims-based definition of number of remaining teeth in Japan: Results from the Longevity Improvement and Fair Evidence Study.

BACKGROUND: Secondary healthcare data use has been increasing in the dental research field. The validity of the number of remaining teeth assessed from Japanese dental claims data has been reported in several studies, but has not been tested in the general population in Japan. OBJECTIVES: To evaluate the validity of the number of remaining teeth assessed from Japanese dental claims data and assess its predictability against subsequent health deterioration. METHODS: We used the claims data of residents of a municipality that implemented oral health screening programs. Using the number of teeth in the screening records as the reference standard, we assessed the validity of the claims-based number of teeth by calculating the mean differences. In addition, we assessed the association between the claims-based number of teeth and pneumococcal disease (PD) or Alzheimer's disease (AD) in adults aged ≥65 years using Cox proportional hazards analyses. RESULTS: Of the 10,154 participants, the mean number of teeth assessed from the claims data was 20.9, that in the screening records was 20.5, and their mean difference was 0.5. During the 3-year follow-up, PD or AD onset was observed in 10.4% (3,212/30,838) and 5.3% (1,589/30,207) of participants, respectively. Compared with participants with ≥20 teeth, those with 1-9 teeth had a 1.29 (95% confidence interval [CI]: 1.17-1.43) or 1.19 (95% CI: 1.04-1.36) times higher risk of developing PD or AD, respectively. CONCLUSION: High validity of the claims-based number of teeth was observed. In addition, the claims-based number of teeth was associated with the risk of PD and AD.

Association between consumption of small fish and all-cause mortality among Japanese: the Japan Multi-Institutional Collaborative Cohort Study.

OBJECTIVE: Although small fish are an important source of micronutrients, the relationship between their intake and mortality remains unclear. This study aimed to clarify the association between intake of small fish and all-cause and cause-specific mortality. DESIGN: We used the data from a cohort study in Japan. The frequency of the intake of small fish was assessed using a validated FFQ. The hazard ratio (HR) and 95 % confidence interval (CI) for all-cause and cause-specific mortality according to the frequency of the intake of small fish by sex were estimated using a Cox proportional hazard model with adjustments for covariates. SETTING: The Japan Multi-Institutional Collaborative Cohort Study. PARTICIPANTS: A total of 80 802 participants (34 555 males and 46 247 females), aged 35-69 years. RESULTS: During a mean follow-up of 9·0 years, we identified 2482 deaths including 1495 cancer-related deaths. The intake of small fish was statistically significantly and inversely associated with the risk of all-cause and cancer mortality in females. The multivariable-adjusted HR (95 % CI) in females for all-cause mortality according to the intake were 0·68 (0·55, 0·85) for intakes 1-3 times/month, 0·72 (0·57, 0·90) for 1-2 times/week and 0·69 (0·54, 0·88) for ≥ 3 times/week, compared with the rare intake. The corresponding HR (95 % CI) in females for cancer mortality were 0·72 (0·54, 0·96), 0·71 (0·53, 0·96) and 0·64 (0·46, 0·89), respectively. No statistically significant association was observed in males. CONCLUSIONS: Intake of small fish may reduce the risk of all-cause and cancer mortality in Japanese females.

Changes in the utilization of outpatient and visiting dental care and per-attendance care cost by age groups during COVID-19 pandemic waves in Japan: A time-series analysis from LIFE study.

BACKGROUND: The influence of the coronavirus disease (COVID-19) pandemic on dental care utilization may have differed according to individual characteristics or type of dental care provision. This study aimed to evaluate the changes in dental care utilization and per-attendance costs by age group and type of dental care during the COVID-19 pandemic in Japan. METHODS: This time-series study used healthcare insurance claims data from 01/07/2019 to 09/27/2021 (143 weeks) from nine municipalities in Japan. Dental care utilization rate per week and average dental care cost per attendance by age groups (0-19y/20-64y/65-74y/≥ 75y) and types of dental care (outpatient/visiting) were used as outcome variables. COVID-19 pandemic waves in Japan were used as predictors: 1st (03/23/2020-05/17/2020), 2nd (06/22/2020-09/27/2020), 3rd (10/26/2020-02/21/2021), 4th (02/22/2021-06/07/2021), and 5th (07/05/2021-09/13/2021) waves. Fixed effect models were employed to estimate the proportional changes. RESULTS: In the fixed effect model, we observed large declines in dental care utilization during the 1st (17.0-22.0%) and 2nd waves (3.0-13.0%) compared to the non-pandemic wave period in all age groups. In contrast, the average dental care cost per attendance increased in all age groups by 5.2-8.6% during the 1st wave. CONCLUSIONS: During the initial wave of the COVID-19 pandemic in Japan, dental care utilization decreased in all age groups, whereas the average dental care cost per attendance increased. The COVID-19 pandemic may have changed the dental care provision pattern towards less frequent and more concentrated dental care to avoid the risk of infection.

Social disconnection and suicide mortality among Japanese older adults: A seven-year follow-up study.

BACKGROUND: Few prospective studies have examined the association between social disconnection and late-life suicide. Therefore, we conducted a large-scale prospective study of older adults in Japan to examine differences in suicide mortality according to specific aspects of social disconnectedness. METHODS: We conducted a nationwide baseline survey of functionally independent older adults (age ≥65 years) from 12 municipalities in Japan from 2010 to 2011. We followed the participants (n = 46,144) for cause of death through December 2017 using vital statistics. Social disconnection was assessed based on the indicators of eating alone, a lack of instrumental/emotional support, no participation in community activities, and no contact with friends. We adopted Cox regression models with multiple imputation for missing values and calculated the population-attributable fraction (PAF). RESULTS: A total of 55 suicide deaths were recorded during an average follow-up of 7 years. Older adults with social disconnection had a marginally increased risk of suicide. The hazard ratio for eating alone vs. eating together was 2.81 (95% confidence interval [CI]: 1.47-5.37). The direction of these associations and point estimations did not largely change after controlling for depressive symptoms, an evident risk factor for suicidal behavior. The PAF indicated that eating alone was attributable to around 1800 (29%) of the suicide deaths among older adults annually in Japan. CONCLUSION: Avoidance of not only depressive symptoms, but also social disconnection including eating alone, is useful in suicide prevention among older adults.

Tooth loss mediates the association between smoking and an increased risk of dementia among older adults: The JAGES prospective cohort study.

AIM: Tooth loss has various causes; however, its cause-specific effects on health outcomes remain unclear. This study evaluated whether the association between past/current smoking and risk of dementia was mediated by tooth loss. MATERIALS AND METHODS: This 9-year-follow-up prospective cohort study targeted adults aged ≥65 years. Dementia incidence during 2013-2019, smoking status (never, past/current) in 2010 and the number of remaining teeth (≤19, ≥20) in 2013 were the outcome, exposure and mediator, respectively. We used causal mediation analysis to fit the Cox proportional hazards model and estimated the hazard ratio (HR) and 95% confidence interval (CI) of the natural indirect effect (NIE) of smoking on dementia incidence through tooth loss and their mediated proportions. RESULTS: Among 32,986 participants (mean age 72.6 years [1 SD = 5.4]; men 48.4%), the dementia incidence during follow-up was 2.11/100 person-years. Tooth loss significantly mediated the association between past/current smoking and dementia incidence; the NIE of fewer remaining teeth for past/current smokers compared to never smokers was HR = 1.03 (95% CI: 1.02-1.05), and the mediated proportion was 18.0%. CONCLUSIONS: Tooth loss significantly mediates the association between past/current smoking and an increased risk of dementia among older adults.

Bivalent mRNA vaccine effectiveness against COVID-19 among older adults in Japan: a test-negative study from the VENUS study.

BACKGROUND: Bivalent COVID-19 vaccines have been implemented worldwide since the booster vaccination campaigns of autumn of 2022, but little is known about their effectiveness. Thus, this study holistically evaluated the effectiveness of bivalent vaccines against infection in older adults in Japan. METHODS: We adopted the test-negative design using COVID-19 test data of individuals, aged ≥ 65 years, residing in three municipalities in Japan, who underwent tests in medical institutions between October 1 and December 30, 2022. Logistic regression analyses were conducted to estimate the odds of testing positive according to vaccination status. Vaccine effectiveness was defined as (1 - odds ratio) × 100%. RESULTS: A total of 3,908 positive and 16,090 negative results were included in the analyses. Receiving a bivalent dose in addition to ≥ 2 monovalent doses was 33.6% (95% confidence interval [CI]: 20.8, 44.3%) more effective than receiving no vaccination, and 18.2% (95% CI: 9.4, 26.0%) more effective than receiving ≥ 2 monovalent doses but not receiving a bivalent vaccination. In addition, the effectiveness peaked at 14-20 days after administration and then gradually declined over time. Furthermore, a bivalent booster dose provided 18.6% (95% CI: 9.9, 26.5%) additional protection among those vaccinated with ≥ 2 monovalent doses, in the absence of a previous infection history. However, we did not find sufficient evidence of effectiveness of bivalent vaccines among previously infected older adults. CONCLUSIONS: Bivalent vaccines are effective against COVID-19 infections among older adults without a history of infection.

Association between awareness of limiting food intake and all-cause mortality: A cohort study in Japan.

BACKGROUND: Improving diets requires an awareness of the need to limit foods for which excessive consumption is a health problem. Since there are limited reports on the link between this awareness and mortality risk, we examined the association between awareness of limiting food intake (energy, fat, and sweets) and all-cause mortality in a Japanese cohort study. METHODS: Participants comprised 58,772 residents (27,294 men; 31,478 women) aged 35-69 years who completed baseline surveys of the Japan Multi-Institutional Collaborative Cohort Study from 2004 to 2014. Hazard ratios (HRs) for all-cause mortality and 95% confidence intervals (CIs) were estimated by sex using a Cox proportional hazard model, with adjustment for related factors. Mediation analysis with fat intake as a mediator was also conducted. RESULTS: The mean follow-up period was 11 years and 2,516 people died. Estimated energy and fat intakes according to the Food Frequency Questionnaire were lower in those with awareness of limiting food intake than in those without this awareness. Women with awareness of limiting fat intake showed a significant decrease in mortality risk (HR=0.73; 95% CI, 0.55 to 0.94). Mediation analysis revealed that this association was due to the direct effect of the awareness of limiting fat intake and that the total effect was not mediated by actual fat intake. Awareness of limiting energy or sweets intake was not related to mortality risk reduction. CONCLUSION: Awareness of limiting food intake had a limited effect on reducing all-cause mortality risk.

Does online communication mitigate the association between a decrease in face-to-face communication and laughter during the COVID-19 pandemic? A cross-sectional study from JACSIS study.

Laughter has a protective effect on human health. The spread of coronavirus disease 2019 (COVID-19) has changed opportunities for face-to-face communication and might decrease opportunities for laughter. This cross-sectional study aimed to investigate whether the decrease in face-to-face communication during the COVID-19 pandemic is associated with a decrease in laughter. Additionally, we investigated whether an increase in online communication mitigates this association. Data from the "Japan COVID-19 and Society Internet Survey (JACSIS)," conducted between August and September 2020, were used. Participants aged 15-79 years were included in this study. The outcome was a decrease in laughter before the onset of the COVID-19 pandemic. The explanatory variables were decreased face-to-face communication with friends and increased online communication (text message, telephone, and video contact). Causal mediation analysis was used to calculate prevalence ratios (PRs) and 95 % confidence intervals (CIs) of the controlled direct effects of increased online communication. Furthermore, the proportions eliminated (PEs) by an increase in online communication were calculated. Among the 25,482 participants, 40.4 % had decreased face-to-face communication and 21.4 % had a decreased frequency of laughter. After adjusting for confounders, a decrease in face-to-face communication was significantly associated with a decrease in laughter (PR = 1.62, 95 %CI = 1.55-1.70). PEs for decrease in laughter were 27.2 % (95 %CI = -2.0 to 56.4) for text-based communication, 36.1 % (95 %CI = 12.3-59.8) for telephone-based communication, and 28.6 % (95 %CI = 0.6-56.6) for video-based communication. Although a decrease in face-to-face communication was associated with a decrease in laughter during the COVID-19 pandemic, online communication, particularly telephone-based communication, mitigated this association.

Reduced number of teeth with and without dental prostheses and low frequency of laughter in older adults: Mediation by poor oral function.

PURPOSE: Laughter is expected to have health-protective effects, but the potential link between tooth loss and laughter remains unclear. Therefore, this study aimed to examine the association between tooth loss and a low frequency of laughter among older adults in Japan, to elucidate whether this association could be mitigated by dental prostheses, and to evaluate the magnitude of the association mediated by poor oral function. METHODS: We used cross-sectional data from 157,708 functionally independent participants aged ≥65 years (46.3% male) from the Japan Gerontological Evaluation Study. A modified Poisson regression model was applied to examine the association between the number of remaining teeth (≥20/10-19/0-9), dental prostheses use, and infrequent laughter (i.e., laughing never or almost never). Causal mediation analysis was performed to assess whether the association was mediated by difficulties in eating hard foods, choking, or dry mouth. RESULTS: Among the participants, 9,129 reported infrequent laughter. Participants with ≤9 and 10-19 teeth who did not use dental prostheses had a 1.29 and 1.14 times higher likelihood of infrequent laughter than those with ≥20 teeth, respectively. Furthermore, difficulty eating hard foods, choking, and dry mouth mediated 22.8%, 0.4%, and 4.3% of the association between fewer remaining teeth and infrequent laughter, respectively. Meanwhile, we did not find evidence for the differences in infrequent laughter between participants with ≤19 teeth using dental prostheses and those with ≥20 teeth. CONCLUSIONS: Tooth loss among individuals without dental prostheses was associated with infrequent laughter, and this association was mediated by poor oral function.

Exploring the relationship between oral health and multiple health conditions: An outcome-wide approach.

PURPOSE: A growing body of evidence suggests that oral health is associated with a wide range of health outcomes; however, opinions tend to vary because of inconsistent findings. This study aimed to simultaneously examine the association between oral health status and multiple health and well-being indicators using outcome-wide epidemiology. METHODS: Data were obtained from the Japan Gerontological Evaluation Study. Oral health status was categorized as: ≥20 teeth, 10-19 teeth with dental prosthesis, 0-9 teeth with prosthesis, 10-19 teeth without prosthesis, and 0-9 teeth without prosthesis. We examined the associations between oral health status in 2013 and 35 health and well-being outcomes in 2019, including physical/cognitive health, psychological distress, subjective health, social well-being, prosocial/altruistic behaviors, and health behaviors, using two databases (n=32,827 and 15,905). RESULTS: Compared to individuals with ≥20 teeth, those with <20 teeth had a 10-33% higher risk of mortality and a 7-10% higher risk of functional disability six years later. Additionally, individuals with fewer than 20 teeth tended to go out less frequently and eat fewer vegetables and fruits. Furthermore, individuals with 0-9 teeth without a prosthesis were more likely to have severe functional disability (risk ratio (RR):1.17, 95% confidence interval (CI):1.05-1.31), engage in fewer intellectual activities (standardized difference: 0.17, 95% CI: 0.10-0.24), and feel more hopeless (RR: 1.21, 95% CI: 1.04-1.41). CONCLUSIONS: The prevention of tooth loss and prosthodontic treatment may be associated with reduced mortality and functional disability, as well as maintenance of intellectual ability, frequency of going out, and improvements in dietary lifestyle.

Compliance Trajectory and Patterns of COVID-19 Preventive Measures, Japan, 2020-2022.

COVID-19 remains a global health threat. Compliance with nonpharmaceutical interventions is essential because of limited effectiveness of COVID-19 vaccines, emergence of highly contagious variants, and declining COVID-19 antibody titers over time. We evaluated compliance with 14 nonpharmaceutical intervention-related COVID-19 preventive behaviors, including mask wearing, ventilation, and surface sanitation, in a longitudinal study in Japan using 4 waves of Internet survey data obtained during 2020-2022. Compliance with most preventive behaviors increased or remained stable during the 2-year period, except for surface sanitation and going out behaviors; compliance with ventilation behavior substantially decreased in winter. Compliance patterns identified from latent class analysis showed that the number of persons in the low compliance class decreased, whereas those in the personal hygiene class increased. Our findings reflect the relaxation of mobility restriction policy in Japan, where the COVID-19 pandemic continues. Policymakers should consider behavioral changes caused by new policies to improve COVID-19 prevention strategies.

Effectiveness of COVID-19 vaccines against infection in Japan: A test-negative study from the VENUS study.

BACKGROUND: Although the effectiveness of coronavirus disease 2019 (COVID-19) vaccines is a crucial public health concern, evidence from Western Pacific countries is limited, including Japan. This study aimed to estimate the COVID-19 vaccines effectiveness (VE) against infection during the Delta variant predominance (July-September 2021) in Japan. METHODS: We performed a test-negative study using COVID-19 test data of ≥20-year-old residents in four municipalities who were tested in medical institutions between July 1 and September 30, 2021. We extracted COVID-19 test data from healthcare claims data, and the vaccination status at the testing date was ascertained using the Vaccination Record System data. Confirmed positive cases were identified using data from the national system for COVID-19, Health Center Real-time Information-sharing System on COVID-19. Logistic regression analyses were conducted to estimate the odds of testing positive according to vaccination status. VE was calculated as (1 - odds ratio) × 100%. RESULTS: This study included 530 positive and 15,650 negative results. Adjusted manufacturer-unspecified VE was 4.1% (95% confidence interval [CI], -36.5-32.6) at 0-13 days after the first dose, 45.2% (95% CI, 13.4-65.3) at ≥14 days after the first dose, 85.2% (95% CI, 69.9-92.7) at 0-13 days after the second dose, and 79.6% (95% CI, 72.6-84.8) at ≥14 days after the second dose. In addition, the VE after the second dose was highest at 14-34 days after the dose (VE, 89.1%; 95% CI, 80.5-93.9). CONCLUSIONS: High real-world effectiveness of COVID-19 vaccines, especially two doses, against infection during the Delta variant predominance in Japan was confirmed.

Dietary Carbohydrate and Fat Intakes and Risk of Mortality in the Japanese Population: the Japan Multi-Institutional Collaborative Cohort Study.

BACKGROUND: Previous cohort studies have yielded contradictory findings regarding the associations of dietary carbohydrate and fat intakes with risks of mortality. OBJECTIVES: We examined long-term associations of carbohydrate and fat intakes with mortality. METHODS: In this cohort study, 34,893 men and 46,440 women aged 35-69 y (mean body mass index of 23.7 and 22.2 kg/m2, respectively) were followed up from the baseline survey (2004-2014) to the end of 2017 or 2018. Intakes of carbohydrate, fat, and total energy were estimated using a food frequency questionnaire. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for all-cause and cause-specific mortality according to percentage of energy intakes of carbohydrate and fat. RESULTS: During a mean 8.9-y follow-up, we identified 2783 deaths (1838 men and 945 women). Compared with men who consumed 50% to <55% of energy from carbohydrate, those who consumed <40% carbohydrate energy experienced a significantly higher risk of all-cause mortality (the multivariable-adjusted HR: 1.59; 95% CI: 1.19-2.12; P-trend = 0.002). Among women with 5 y or longer of follow-up, women with high-carbohydrate intake recorded a higher risk of all-cause mortality; the multivariable-adjusted HR (95% CI) was 1.71 (0.93-3.13) for ≥65% of energy from carbohydrate compared with that for 50% to <55% (P-trend = 0.005). Men with high fat intake had a higher risk of cancer-related mortality; the multivariable-adjusted HR (95% CI) for ≥35% was 1.79 (1.11-2.90) compared with that for 20% to <25%. Fat intake was marginally inversely associated with risk of all-cause and cancer-related mortality in women (P-trend = 0.054 and 0.058, respectively). CONCLUSIONS: An unfavorable association with mortality is observed for low-carbohydrate intake in men and for high-carbohydrate intake in women. High fat intake can be associated with a lower mortality risk in women among Japanese adults with a relatively high-carbohydrate intake.

Oral status and incident functional disability: A 9-year prospective cohort study from the JAGES.

INTRODUCTION: The population-attributable risk of oral status for incident functional disability remains unknown. We investigated the impact of a range of oral statuses (number of remaining teeth, chewing difficulty, dry mouth, and choking) on incident functional disability. METHODS: Participants (n = 44,083) aged ≥ 65 years from the Japan Gerontological Evaluation Study were evaluated. The outcome variable was incident functional disability, and the explanatory variables were four select oral statuses. The possible confounders were included as covariates. Using the Cox proportional hazards model, we calculated hazard ratios (HRs), 95% confidence intervals (CIs), and their population-attributable fractions (PAFs). RESULTS: The mean age of the participants was 73.7 (standard deviation=6.0) years at baseline, and 53.2% were women. A total of 8,091 participants (18.4%) developed functional disabilities during the follow-up period. Among the four oral statuses, the incidence rate of functional disability was the highest in those with chewing difficulty (3.27/100 person-years), followed by those with dry mouth (3.20/100 person-years), choking (3.10/100 person-years), and ≤19 remaining teeth (2.89/100 person-years). After adjusting for all covariates, chewing difficulty showed the highest risk of functional disability (HR=1.22, 95%CI=1.16-1.28), followed by ≤19 remaining teeth (HR=1.18, 95%CI=1.12-1.25), dry mouth (HR=1.18, 95%CI=1.12-1.24), and choking (HR=1.10, 95%CI=1.04-1.17). Regarding PAF, ≤19 remaining teeth (12.0%) were the largest, followed by chewing difficulty (7.2%), dry mouth (4.6%), and choking (1.9%). CONCLUSIONS: Maintaining a good oral status may reduce the risk of functional disability later in life. Given its population contribution, tooth loss had the largest impact among the four oral conditions.

Sex-specific Relationship Between Stress Coping Strategies and All-cause Mortality: Japan Multi-Institutional Collaborative Cohort Study.

BACKGROUND: Stress coping strategies are related to health outcomes. However, there is no clear evidence for sex differences between stress-coping strategies and mortality. We investigated the relationship between all-cause mortality and stress-coping strategies, focusing on sex differences among Japanese adults. METHODS: A total of 79,580 individuals aged 35-69 years participated in the Japan Multi-Institutional Collaborative Cohort Study between 2004 and 2014 and were followed up for mortality. The frequency of use of the five coping strategies was assessed using a questionnaire. Sex-specific, multivariable-adjusted hazard ratios (HRs) for using each coping strategy ("sometimes," and "often/very often" use versus "very few" use) were computed for all-cause mortality. Furthermore, relationships were analyzed in specific follow-up periods when the proportion assumption was violated. RESULTS: During the follow-up (median: 8.5 years), 1,861 mortalities were recorded. In women, three coping strategies were related to lower total mortality. The HRs for "sometimes" were 0.81 (95% confidence interval [CI], 0.67-0.97) for emotional expression, 0.79 (95% CI, 0.66-0.95) for emotional support-seeking, and 0.80 (95% CI, 0.66-0.98) for disengagement. Men who "sometimes" used emotional expression and sometimes or often used problem-solving and positive reappraisal had a 15-41% lower HRs for all-cause mortality. However, those relationships were dependent on the follow-up period. There was evidence that sex modified the relationships between emotional support-seeking and all-cause mortality (P for interaction = 0.03). CONCLUSION: In a large Japanese sample, selected coping strategies were associated with all-cause mortality. The relationship of emotional support-seeking was different between men and women.

Secondhand Aerosol Exposure From Heated Tobacco Products and Its Socioeconomic Inequalities in Japan: The JASTIS Study 2017-2020.

INTRODUCTION: The growing use of heated tobacco products (HTPs) has raised concerns about secondhand aerosol (SHA) from HTPs, but few studies have been reported on it. This study aimed to investigate the trends in SHA exposure and their socioeconomic inequalities in Japan. METHODS: The prevalence of SHA exposure from 2017 to 2020 was estimated using longitudinal internet survey data of 5221 participants, aged 20-69 years in 2017 (baseline), with adjustments using inverse probability weighting for "being a participant in an internet survey". Multivariable modified Poisson regression models were applied to examine the association between socioeconomic status (ie, educational attainment and equivalent income) at baseline and SHA exposure in 2020 with adjustments for sex and age. RESULTS: The estimated prevalence of SHA exposure has consistently increased from 4.5% in 2017 to 10.8% in 2020. Lower educational attainment was associated with a higher risk of SHA exposure (p for trend = 0.010). The covariate-adjusted risks of SHA exposure in participants with a low-education and middle-education level were 1.57 and 1.34 times higher, respectively, than in those with a high-education level. However, significant differences in risks of SHA exposure between participants with low-, middle-, and high-income levels were not observed. Meanwhile, participants with a low-education and middle-education level also had 1.87 and 1.61 times higher risks of secondhand smoke (SHS) exposure from combustible cigarettes than those with a high-education level, respectively. CONCLUSIONS: Our study revealed a rapid increase in SHA exposure and the existence of educational inequalities in both SHA and SHS exposure. IMPLICATIONS: Using longitudinal internet cohort survey data, we found that the prevalence of exposure to secondhand aerosol (SHA) from heated tobacco products (HTPs) rapidly increased to 10.8% in 2020 in Japan. Furthermore, people with lower educational attainment were at higher risk of SHA exposure, suggesting that extensive educational interventions may be necessary to inform the public that although emissions from HTPs contain significantly lesser amounts of harmful and potentially harmful constituents and these compounds than cigarette smoke, they are not harmless and still entail risks, and its long-term effects are unknown. Therefore, future extensive monitoring of SHA exposure is needed.

Occasions for laughter and dementia risk: Findings from a six-year cohort study.

AIM: Currently, there is little evidence on the relationship between laughter and the risk of dementia, and since laughter is mainly a social behavior, we aimed to examine the association between various occasions for laughter and the risk of dementia in Japanese older adults. METHODS: We draw upon 6-year follow-up data from the Japan Gerontological Evaluation Study, including 12 165 independent older adults aged 65 years or over. Occasions for laughter were assessed using a questionnaire, while dementia was diagnosed using the standardized dementia scale of the long-term care insurance system in Japan. Cox proportional hazards models were estimated, yielding hazard ratios and 95% confidence intervals (CIs). RESULTS: The multivariable hazard ratio of dementia incidence for all participants in the groups for high versus low variety of occasions for laughter was 0.84 (95% CI: 0.72-0.98, P for trend <0.001). A greater variety of occasions for laughter was associated with a lower risk of dementia 0.78 (95% CI: 0.63-0.96, P for trend <0.001) among women, but was less pronounced for men, with significant associations only for the medium group. Laughing during conversations with friends, communicating with children or grandchildren, and listening to the radio were primarily associated with decreased risk. CONCLUSION: A greater variety of laughter occasions in individual and social settings was associated with a reduced risk of dementia. Geriatr Gerontol Int 2022; 22: 392-398.

Effect of the interaction between physical activity and estimated macronutrient intake on HbA1c: population-based cross-sectional and longitudinal studies.

INTRODUCTION: Healthy diet and physical activity (PA) are essential for preventing type 2 diabetes, particularly, a combination of diet and PA. However, reports on interaction between PA and diet, especially from large epidemiological studies, are limited. We investigated the effect of interaction between PA and macronutrient intake on hemoglobin A1c (HbA1c) levels in the general population. RESEARCH DESIGN AND METHODS: We conducted a cross-sectional study of 55 469 men and women without diabetes who participated in the baseline survey of the Japan Multi-Institutional Collaborative Cohort Study. A self-administered questionnaire ascertained PA and macronutrient intake (carbohydrate, fat, and protein). Multiple linear regression analyses were performed to adjust for confounding variables and examine the interactions. In addition, we conducted a longitudinal study during a 5-year period within a subcohort (n=6881) with accelerometer-assessed PA data. RESULTS: Overall, PA had a weak inverse association (ß=-0.00033, p=0.049) and carbohydrate intake had a strong positive association (ß=0.00393, p<0.001) with HbA1c. We observed a tendency of interactions between PA and carbohydrate or fat intake, but not protein intake, on HbA1c levels after adjusting for age, sex, study area, total energy intake, alcohol consumption, smoking, and medication for hypertension or hypercholesterolemia (Pinteraction=0.054, 0.006, and 0.156, respectively). The inverse associations between PA and HbA1c level were more evident in participants with high-carbohydrate (or low-fat) intake than in participants with low-carbohydrate (or high-fat) intake. Although further adjustment for body mass index slightly attenuated the above interactions (Pinteraction=0.098 for carbohydrate and 0.068 for fat), the associations between PA and HbA1c level in stratified analyses remained unchanged. Similar associations and interactions were reproduced in the longitudinal study. CONCLUSIONS: The present results suggest that the effect of PA on HbA1c levels is modified by intake of macronutrient composition.

Does laughing with others lower the risk of functional disability among older Japanese adults? The JAGES prospective cohort study.

While laughter is evoked mainly in social contexts, the potential link between laughter in daily life and health benefits is unclear. This study aimed to examine the association between laughter in daily life and the onset of functional disability among older adults in Japan. Data were obtained from a 6-year follow-up cohort of 12,571 participants (46.1% male) in the Japan Gerontological Evaluation Study, aged ≥65 years, who could independently perform daily activities. We evaluated their laughter in daily life from three perspectives: the types of situations in which people laugh, the number of situations in which people laugh with others, and the persons with whom people laugh. Using the Cox proportional hazards model, the risk of functional disability was estimated. A total of 1420 functional disabilities were observed during follow-up. After adjusting for potential confounders, participants who laughed with others (e.g., during conversations with friends) were at a reduced risk of functional disability (hazard ratio, 0.77; 95% confidence interval, 0.65-0.92) than those who laughed alone (e.g., during watching television). Similarly, the number of situations to laugh with others was inversely associated with the risk of functional disability (Ptrend < 0.001). Laughing in a conversation with friends reduced the risk of functional disability by approximately 30% compared to laughing alone. Overall, laughing with others was associated with a reduced risk of functional disability. Having more situations to laugh with others or at least the situation to laugh with friends might contribute to reducing the risk of functional disability later in life.

Prolonged sedentary time under the state of emergency during the first wave of coronavirus disease 2019: Assessing the impact of work environment in Japan.

OBJECTIVES: The coronavirus disease 2019 (COVID-19) outbreak and the resulting state of emergency have restricted work environments, which may contribute to increased duration of sedentary behaviors. This study investigated the self-reported sedentary time of Japanese workers during and after the first state of emergency (April 7 to May 25, 2020) and examined differences in sedentary time after starting work from home and according to job type. METHODS: We used cross-sectional data from the Japan COVID-19 and Society Internet Survey, a web-based questionnaire survey conducted from August to September 2020 (n = 11,623; age range 15-79 years; 63.6% male). Prolonged sedentary time was calculated by subtracting the sedentary time after the state of emergency (defined as the normal sedentary time) from that during the emergency, with adjustments using inverse probability weighting for being a respondent in an internet survey. RESULTS: An increase in sedentary time of at least 2 hours was reported by 12.8% of respondents who started working from home during the state of emergency, including 9.7% of salespersons and 7.7% of desk workers. After adjusting for potential confounders, the multivariate-adjusted odds ratios (ORs) for a prolonged sedentary time ≥2 hours was significantly higher in respondents who started to work from home (OR: 2.14, 95% confidence interval: 1.78-2.57), and certain job types (desk workers; OR: 1.56, 95% CI: 1.27-1.91, salespersons; OR: 2.03, 95% CI: 1.64-2.51). CONCLUSIONS: Working from home and non-physical work environments might be important predictors of prolonged sedentary time.