Background While laughter is broadly recognized as a good medicine, a potential preventive effect of laughter on disability and death is still being debated. Accordingly, we investigated the association between the frequency of laughter and onset of functional disability and all-cause mortality among the older adults in Japan. Methods The data for a 3-year follow-up cohort including 14,233 individuals (50.3% men) aged ≥65 years who could independently perform the activities of daily living and participated in the Japan Gerontological Evaluation Study were analyzed. The participants were classified into four categories according to their frequency of laughter (almost every day, 1–5 days/week, 1–3 days/month, and never or almost never). We estimated the risks of functional disability and all-cause mortality in each category using a Cox proportional hazards model. Results During follow-up, 605 (4.3%) individuals developed functional disability, identified by new certification for the requirement of Long-Term Care Insurance, and 659 (4.6%) deaths were noted. After adjusting for the potential confounders, the multivariate-adjusted hazard ratio of functional disability increased with a decrease in the frequency of laughter ( P for trend = 0.04). The risk of functional disability was 1.42 times higher for individuals who laughed never or almost never than for those who laughed almost every day. No such association was observed with the risk of all-cause mortality ( P for trend = 0.39). Conclusions Low frequency of laughter is associated with increased risks of functional disability. Laughter may be an early predictor of functional disability later on in life.

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.

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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.