Association between Japanese Diet Adherence and Muscle Weakness in Japanese Adults Aged ≥50 Years: Findings from the JSTAR Cohort Study.

Japanese diet adherence has been inversely correlated with muscle weakness. In this study, we aimed to validate that association. Longitudinal data from 1699 individuals aged ≥50 years (mean age 62.5 ± 6.9 years, 50.4% female) at two time points (2007 and 2011) were used. Participants without muscle weakness from several regions in Japan were included. The 12-component revised Japanese Diet Index (rJDI12) classified by tertiles assessed adherence to the Japanese dietary pattern. Muscle weakness was defined as a handgrip strength of ˂18 kg for females and ˂28 kg for males based on the Asian Working Group for Sarcopenia criteria 2019. A multivariate logistic approach was used to determine the relationship between rJDI12 tertile and the occurrence of muscle weakness by calculating the odds ratio (OR) and its 95% confidence interval (95% CI) throughout the observation period. Muscle weakness was negatively correlated with the highest rJDI12 tertile (OR [95% CI] 0.891 [0.814, 0.973] for T3). This association was consistent in sensitivity analyses with multiple imputations of missing values. Closely following the Japanese dietary pattern appears to reduce the occurrence of muscle weakness among the aging population in this study, suggesting it may prevent frailty and sarcopenia in the aging population.

Trimethylamine N-oxide and risk of inflammatory bowel disease: A Mendelian randomization study.

A previous study suggested that inflammatory bowel disease (IBD) patients have low plasma levels of trimethylamine N-oxide (TMAO). In the present study, we examined this hypothesis using Mendelian randomization analysis. We used summary statistics data for single-nucleotide polymorphisms associated with plasma levels of TMAO, and the corresponding data for IBD from a genome-wide association meta-analysis of 59,957 individuals (25,042 diagnosed IBD cases, 34,915 controls). The association between genetically predicted plasma TMAO levels and IBD showed odds ratios (95% confidence interval [CI]) per 1 interquartile range increment (per 2.4 µmol/L) in TMAO levels were 0.91 (0.81-1.01, P = .084) for IBD, 0.88 (0.76-1.02, P = .089) for ulcerative colitis, 0.91 (0.79-1.05, P = .210) for Crohn disease. There was no evidence for pleiotropy based on the Mendelian randomization-Egger regression analyses (P-intercept = 0.669 for IBD). Further investigations would be needed to understand the causal relationship between TMAO and IBD.

Impact of Household Economic and Mothers' Time Affluence on Obesity in Japanese Preschool Children: A Cross-sectional Study.

Although the association between household economic affluence and children's obesity has been reported, the association between mothers' time affluence and obesity remains unclear. We conducted a cross-sectional study using Japanese national survey data (2015). The target population was 2-6-year-old preschool children and their mothers. Subjective household economic affluence and mothers' time affluence were divided into "affluent," "neither," "less affluent," and "non-affluent" groups. Obesity was defined based on the International Obesity Task Force. A logistic regression model was conducted to examine the association between household economic affluence, mothers' time affluence, and children's obesity. A total of 2254 respondents were included in the present analysis. The lower household economic affluence was not significantly associated with higher rates of children's obesity (odds ratio (OR) for the "non-affluent" compared with the "affluent" group was 1.68 (95% CI, 0.93-3.03)). A lower mothers' time affluence was not significantly associated with higher rates of children's obesity (OR for the "non-affluent" compared with the "affluent" group was 1.67 (95% CI, 0.92-3.03)). The prevalence of obesity was not synergistically higher when lower household economic affluence and lower mothers' time affluence were combined.

Polyunsaturated fatty acids and risk of anorexia nervosa: A Mendelian randomization study.

PURPOSE: Observational studies have suggested that polyunsaturated fatty acids (PUFAs) decrease the risk of anorexia nervosa (AN). In the present study, we examined this hypothesis using a Mendelian randomization analysis. METHODS: We used summary statistics for single-nucleotide polymorphisms associated with plasma levels of n-6 (linoleic acid and arachidonic acid) and n-3 PUFAs (alpha-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid) and the corresponding data for AN from a genome-wide association meta-analysis of 72,517 individuals (16,992 diagnosed AN cases and 55,525 controls). RESULTS: None of the genetically predicted PUFAs were significantly associated with the risk of AN; odds ratios (95 % confidence interval) per 1 standard deviation increase in PUFA levels were 1.03 (0.98, 1.08) for linoleic acid, 0.99 (0.96, 1.03) for arachidonic acid, 1.03 (0.94, 1.12) for alpha-linolenic acid, 0.98 (0.90, 1.08) for eicosapentaenoic acid, 0.96 (0.91, 1.02) for docosapentaenoic acid, and 1.01 (0.90, 1.36) for docosahexaenoic acid. LIMITATION: Only two types of fatty acids (LA and DPA) can be used for pleiotropy tests using the MR-Egger intercept test. CONCLUSION: This study does not support the hypothesis that PUFAs decrease the risk of AN.

Association of Japanese and Mediterranean Dietary Patterns with Muscle Weakness in Japanese Community-Dwelling Middle-Aged and Older Adults: Post Hoc Cross-Sectional Analysis.

The association of Japanese and Mediterranean dietary patterns with muscle weakness in middle-aged and older Japanese individuals is unclear. This cross-sectional study investigated the association between Japanese and Mediterranean dietary patterns and muscle weakness in community-dwelling, middle-aged, and older Japanese individuals (enrolled from 2007 to 2011). Based on the dietary consumption information obtained from the brief self-administered diet history questionnaire, we assessed adherence to the Japanese (12-component revised Japanese diet index (rJDI12)) and Mediterranean (alternate Mediterranean diet (aMed) score) dietary patterns. Muscle weakness was defined as handgrip strength <28 and <18 kg for men and women, respectively. Logistic regression was used to ascertain the relationship between dietary pattern and muscle weakness. In our study, with 6031 participants, the Japanese, but not Mediterranean, dietary pattern was inversely associated with muscle weakness (p for trend = 0.031 and 0.242, respectively). In the model adjusted for confounders, including energy intake, the highest quartile of rJDI12 scores (9-12 points), and the rJDI12 scores, entered as continuous variables, showed an independent association (odds ratio (95% CI), 0.703 (0.507-0.974), and 0.933 (0.891-0.977), respectively). Our findings showed that adherence to the Japanese dietary pattern is associated with a low prevalence of muscle weakness.

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.

Did Children in Single-Parent Households Have a Higher Probability of Emotional Instability during the COVID-19 Pandemic? A Nationwide Cross-Sectional Study in Japan.

The influence of public health measures against COVID-19 in Japan on child mental health by household type is unknown. This study aimed to investigate whether COVID-19 and the declaration of a state of emergency in Japan affected children's mental health between single-parent and two-parent households disproportionately. A large cross-sectional online survey was conducted from August to September 2020. The study included 3365 parents with children aged 0-14 years old who reported their children's mental status during the declared state of emergency. Emotional instability was reported dichotomously by parents. As the primary result, the probability of emotional instability was higher in single-parent households compared with that in two-parent households after adjustments for potential covariates; the adjusted prevalence ratio (95% CI) was 1.26 (1.07-1.49). Our findings suggest a disproportionate impact on children's mental health due to the pandemic.

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.

Reduction in total and major cause-specific mortality from tobacco smoking cessation: a pooled analysis of 16 population-based cohort studies in Asia.

BACKGROUND: Little is known about the time course of mortality reduction following smoking cessation in Asians who have smoking behaviours distinct from their Western counterparts. We evaluated the level of reduction in all-cause, cardiovascular disease (CVD) and lung cancer mortality by years since quitting smoking, in Asia. METHODS: Using Cox regression, we analysed individual participant data (n = 709 151) from 16 prospective cohorts conducted in China, Japan, Korea/Singapore, and India/Bangladesh, separately by cohorts. Cohort-specific hazard ratios (HRs) were combined using a random-effects meta-analysis. RESULTS: During a mean follow-up of 12.0 years, 108 287 deaths were ascertained-35 658 from CVD and 7546 from lung cancer. Among Asian men, a dose-response relationship of risk reduction in deaths from all causes, CVD and lung cancer was observed with an increase in years after smoking cessation. Compared with never smokers, however, all-cause and CVD mortality among former smokers remained elevated 10-14 years after quitting [multivariable-adjusted HR (95% confidence interval (CI) = 1.25 (1.13-1.37) and 1.20 (1.02-1.41), respectively]. Lung cancer mortality stayed almost 2-fold higher than among never smokers 15-19 years after smoking cessation [1.97 (1.41-2.73)], particularly among former heavy smokers [2.62 (1.71-4.00)]. Women who quitted for ≥5 years retained a significantly elevated mortality from all causes, CVD and lung cancer. Overall patterns of the cessation-mortality associations were similar across countries. CONCLUSIONS: Our findings suggest that adverse effects of tobacco smoking persist for an extended time period, even for more than two decades, which is beyond the time windows defined in current clinical guidelines for risk assessment of lung cancer and CVD.

Association between RNF213 c.14576G>A Variant (rs112735431) and Peripheral Pulmonary Artery Stenosis in Moyamoya Disease.

BACKGROUND: Moyamoya disease (MMD) and peripheral pulmonary artery stenosis (PPAS) are relatively rare and demonstrate steno-occlusive vascular lesions in different organs. Genetic studies identified RNF213 polymorphism c.14576G>A (rs112735431) as a susceptibility variant for East Asian MMD. RNF213 polymorphism c.14576G>A is further associated with various vascular lesions of other organs. In this study, we aimed to clarify the incidence and clinical manifestations of PPAS in MMD patients and analyze the correlation between RNF213 genotype and PPAS. METHODS: This retrospective case-control study investigated the association between RNF213 polymorphism and PPAS in 306 MMD/quasi-MMD patients, reviewing the medical charts and imaging records of consecutive patients with MMD admitted from January 2015 to December 2020. RESULTS: PPAS was observed in 3 MMD/quasi-MMD patients (0.98%, 3/306). RNF213 polymorphism c.14576G>A was determined for all 306 MMD/quasi-MMD patients. The incidence of PPAS in RNF213-wildtype, RNF213-heterozygote, and RNF213-homozygote MMD/quasi-MMD patients was 0% (0/101), 0.5% (1/200), and 40% (2/5), respectively. The association between PPAS and homozygote polymorphism of RNF213 c.14576G>A was statistically significant in MMD/quasi-MMD patients (p = 0.0018). In all cases, pulmonary artery hypertension due to PPAS was evident during their childhood and young adolescent stages. Surgical indications for MMD were discouraged in 1 case due to her severe cardiopulmonary dysfunction. CONCLUSIONS: The homozygote variant of RNF213 polymorphism c.14576G>A can be a potential predisposing factor for PPAS in MMD/quasi-MMD patients. Despite the relatively rare entity, PPAS should be noted to determine surgical indications for MMD/quasi-MMD patients.

Protein Nutritional Status and Frailty: A Mendelian Randomization Study.

BACKGROUND: Observational studies have suggested that better protein nutritional status may contribute to prevention of frailty. OBJECTIVE: We sought to examine this hypothesis using a Mendelian randomization (MR) analysis. METHODS: We conducted a two-sample MR study using GWAS summary statistics data of the UK Biobank. We applied genetically predicted serum albumin as a primary exposure measure and serum total protein as a secondary exposure measure. The outcome measure was the Rockwood frailty index (FI) based on 49 deficits from 356,432 individuals (53.3% of them were women, with a mean ± SD age of 56.7 ± 8.0 y. The association between serum protein measures and FI was mainly analyzed by use of the inverse variance weighted method. RESULTS: A genetically predicted serum albumin concentration was not statistically significantly associated with FI in the full sample. However, in women, we observed a preventive association between genetically predicted serum albumin and FI (ß = -0.172 per g/L; 95% CI: -0.336, -0.007; P = 0.041). In the full sample, genetically predicted serum total protein was inversely associated with FI (ß: -0.153 per g/L; 95% CI: -0.251, -0.056; P = 0.002). In both women and men, higher serum total protein was significantly inversely associated with FI; regression coefficients were -0.148 per g/L (95% CI: -0.287, -0.009; P = 0.037) for women, -0.154 per g/L (95% CI: -0.290, -0.018; P = 0.027) for men. CONCLUSIONS: The present MR study implies that better protein nutritional status modestly contributes to reducing the risk of frailty.

Coffee and tea consumption and mortality from all causes, cardiovascular disease and cancer: a pooled analysis of prospective studies from the Asia Cohort Consortium.

BACKGROUND: Accumulating evidence suggests that consuming coffee may lower the risk of death, but evidence regarding tea consumption in Asians is limited. We examined the association between coffee and tea consumption and mortality in Asian populations. METHODS: We used data from 12 prospective cohort studies including 248 050 men and 280 454 women from the Asia Cohort Consortium conducted in China, Japan, Korea and Singapore. We estimated the study-specific association of coffee, green tea and black tea consumption with mortality using Cox proportional-hazards regression models and the pooled study-specific hazard ratios (HRs) using a random-effects model. RESULTS: In total, 94 744 deaths were identified during the follow-up, which ranged from an average of 6.5 to 22.7 years. Compared with coffee non-drinkers, men and women who drank at least five cups of coffee per day had a 24% [95% confidence interval (CI) 17%, 29%] and a 28% (95% CI 19%, 37%) lower risk of all-cause mortality, respectively. Similarly, we found inverse associations for coffee consumption with cardiovascular disease (CVD)-specific and cancer-specific mortality among both men and women. Green tea consumption was associated with lower risk of mortality from all causes, CVD and other causes but not from cancer. The association of drinking green tea with CVD-specific mortality was particularly strong, with HRs (95% CIs) of 0.79 (0.68, 0.91) for men and 0.78 (0.68, 0.90) for women who drank at least five cups per day of green tea compared with non-drinkers. The association between black tea consumption and mortality was weak, with no clear trends noted across the categories of consumption. CONCLUSIONS: In Asian populations, coffee consumption is associated with a lower risk of death overall and with lower risks of death from CVD and cancer. Green tea consumption is associated with lower risks of death from all causes and CVD.

Social Participation and Healthy Aging Among the Older Japanese: The Ohsaki Cohort 2006 Study.

BACKGROUND: Our study examined the association between social participation and healthy aging using a community-based cohort study among Japanese older adults. METHODS: This prospective study was conducted in Ohsaki City, Japan, and included 7226 participants aged ≥65 years at the baseline survey in 2006. We obtained information on frequency of participation in 3 types of community activities (ie, neighborhood activities, hobbies, and volunteer activities) at baseline. Exposure was measured by the number of types of community activities participated in and participants were categorized into 4 groups (ie, none, 1 type, 2 types, and 3 types). The primary outcome was healthy aging as assessed by a questionnaire survey conducted in 2017, and was defined as meeting the following 4 criteria: free of disability, free of depression, high health-related quality of life, and high life satisfaction. We used multiple logistic regression models to calculate the corresponding odds ratios and 95% confidence intervals. RESULTS: During 11 years of follow-up, 574 (7.9%) participants attained healthy aging. Compared with participants not participating in any activity, the multivariable-adjusted odds ratios (95% confidence intervals) were 1.90 (1.40, 2.59) for those participating in 1 type, 2.49 (1.84, 3.38) for 2 types, and 3.06 (2.30, 4.07) for 3 types (p for trend < .0001). Furthermore, for each type of community activity, a higher frequency of participation was related to higher probability of healthy aging. CONCLUSIONS: Our study suggests that social participation is associated with the promotion of healthy aging, and that the benefits were observed across different types of community activities.

Frailty and the risk of dementia: is the association explained by shared environmental and genetic factors?

BACKGROUND: Frailty has been identified as a risk factor for cognitive impairment and dementia. However, it is not known whether familial factors, such as genetics and shared environmental factors, underlie this association. We analyzed the association between frailty and the risk of dementia in a large twin cohort and examined the role of familial factors in the association. METHODS: The Rockwood frailty index (FI) based on 44 health deficits was used to assess frailty. The population-level association between FI and the risk of all-cause dementia was analyzed in 41,550 participants of the Screening Across the Lifespan Twin (SALT) study (full sample, aged 41-97 years at baseline), using Cox and competing risk models. A subsample of 10,487 SALT participants aged 65 and older who received a cognitive assessment (cognitive sample) was used in a sensitivity analysis to assess the effect of baseline cognitive level on the FI-dementia association. To analyze the influence of familial effects on the FI-dementia association, a within-pair analysis was performed. The within-pair model was also used to assess whether the risk conferred by frailty varies by age at FI assessment. RESULTS: A total of 3183 individuals were diagnosed with dementia during the 19-year follow-up. A 10% increase in FI was associated with an increased risk of dementia (hazard ratio [HR] 1.17 (95% confidence interval [CI] 1.07, 1.18)) in the full sample adjusted for age, sex, education, and tobacco use. A significant association was likewise found in the cognitive sample, with an HR of 1.13 (95% CI 1.09, 1.20), adjusted for age, sex, and cognitive level at baseline. The associations were not attenuated when adjusted for APOE ɛ4 carrier status or considering the competing risk of death. After adjusting for familial effects, we found no evidence for statistically significant attenuation of the effect. The risk conferred by higher FI on dementia was constant after age 50 until very old age. CONCLUSIONS: A higher level of frailty predicts the risk of dementia and the association appears independent of familial factors. Targeting frailty might thus contribute to preventing or delaying dementia.

Fatty Acids and Frailty: A Mendelian Randomization Study.

BACKGROUND: Observational studies have suggested that fatty acids such as higher levels of n-3 polyunsaturated fatty acids (PUFAs) may prevent frailty. By using Mendelian randomization analysis, we examined the relationship between fatty acids and frailty. METHODS: We used summary statistics data for single-nucleotide polymorphisms associated with plasma levels of saturated fatty acids (palmitic acid, stearic acid), mono-unsaturated fatty acids (MUFAs) (palmitoleic acid, oleic acid), n-6 PUFAs (linoleic acid, arachidonic acid), and n-3 PUFAs (alpha-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, docosahexaenoic acid), and the corresponding data for frailty index (FI) in 356,432 individuals in the UK Biobank. RESULTS: Although there were no robust associations on the MUFAs or the PUFAs, genetically predicted higher plasma stearic acid level (one of saturated fatty acids) was statistically significantly associated with higher FI (ß = 0.178; 95% confidence interval = -0.050 to 0.307; p = 0.007). Such a relationship was also observed in a multivariate MR (ß = 0.361; 95% confidence interval = 0.155 to 0.567; p = 0.001). Genetically predicted higher palmitic acid was also significantly associated with higher FI (ß = 0.288; 95% confidence interval = 0.128 to 0.447; p < 0.001) in the multivariate MR analysis. CONCLUSIONS: The present MR study implies that saturated fatty acids, especially stearic acid, is a risk factor of frailty.

Association between weight loss since the age of 20 years and the risk of suicide death: A population-based cohort study.

BACKGROUND: Past studies have demonstrated that body mass index (BMI) is inversely associated with the risk of suicide death. However, to our knowledge, no study has investigated the association between long-term weight change and the risk of suicide death. The purpose of this study was to investigate the association between weight change from the age of 20 years to middle or older age and the risk of suicide death in a population-based cohort. METHODS: We analyzed follow-up data for 41,746 participants aged ≥40 years and calculated percent weight change from age 20 years to that at the survey baseline (mean age: 61.2 years). A Cox model was used to estimate the multivariate-adjusted hazard ratios (HRs) for suicide death. RESULTS: The mean duration of follow up was 6.9 years, and suicide death was documented for 80 persons. Weight loss >5% (WL) was associated with a significantly higher risk of suicide death, with a multivariate-adjusted HR of 1.92 (95% confidence interval: 1.02-3.63). On the other hand, weight gain tended to be associated with a lower risk of suicide death. The significantly higher risk of suicide death observed among those showing WL did not change after excluding participants with a history of disease or psychological distress. LIMITATIONS: No information was given regarding the reasons for weight change and suicide death. CONCLUSIONS: The present results suggest that physicians should pay attention to individuals who lose weight from early adulthood because they could be at increased risk for suicide.

Association between participation in the government subsidy programme for domestic travel and symptoms indicative of COVID-19 infection in Japan: cross-sectional study.

OBJECTIVE: To investigate the association between participation in government subsidies for domestic travel (subsidise up to 50% of all travel expenses) introduced nationally in Japan on 22 July 2020 and the incidence of symptoms indicative of COVID-19 infections. DESIGN: Cross-sectional analysis of nationally representative survey data. SETTING: Internet survey conducted between 25 August and 30 September 2020 in Japan. Sampling weights were used to calculate national estimates. PARTICIPANTS: 25 482 survey respondents (50.3% (12 809) women; mean (SD) age, 48.8 (17.4) years). MAIN OUTCOME MEASURES: Incidence rate of five symptoms indicative of the COVID-19 infection (high fever, sore throat, cough, headache, and smell and taste disorder) within the past month of the survey, after adjustment for characteristics of individuals and prefecture fixed effects (effectively comparing individuals living in the same prefecture). RESULTS: At the time of the survey, 3289 (12.9%) participated in the subsidy programme. After adjusting for potential confounders, we found that participants in the subsidy programme exhibited higher incidence of high fever (adjusted rate, 4.7% for participants vs 3.7% for non-participants; adjusted OR (aOR) 1.83; 95% CI 1.34 to 2.48; p<0.001), sore throat (19.8% vs 11.3%; aOR 2.09; 95% CI 1.37 to 3.19; p=0.002), cough (19.0% vs 11.3%; aOR 1.96; 95% CI 1.26 to 3.01; p=0.008), headache (29.2% vs 25.5%; aOR 1.24; 95% CI 1.08 to 1.44; p=0.006) and smell and taste disorder (2.6% vs 1.8%; aOR 1.98; 95% CI 1.15 to 3.40; p=0.01) compared with non-participants. These findings remained qualitatively unaffected by additional adjustment for the use of 17 preventative measures (eg, social distancing, wearing masks and handwashing) and fear against the COVID-19 infection. CONCLUSIONS: The participation of the government subsidy programme for domestic travel was associated with a higher probability of exhibiting symptoms indicative of the COVID-19 infection.