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.

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.

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.

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.

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 (β = -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 (β: -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.

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.

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 (β = 0.178; 95% confidence interval = -0.050 to 0.307; p = 0.007). Such a relationship was also observed in a multivariate MR (β = 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 (β = 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.

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.

Associations of coffee and tea consumption with lung cancer risk

Associations of coffee and tea consumption with lung cancer risk have been inconsistent, and most lung cancer cases investigated were smokers. Included in this study were over 1.1 million participants from 17 prospective cohorts. Cox regression analyses were conducted to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Potential effect modifications by sex, smoking, race, cancer subtype and coffee type were assessed. After a median 8.6 years of follow-up, 20 280 incident lung cancer cases were identified. Compared with noncoffee and nontea consumption, HRs (95% CIs) associated with exclusive coffee drinkers (≥2 cups/d) among current, former and never smokers were 1.30 (1.15-1.47), 1.49 (1.27-1.74) and 1.35 (1.15-1.58), respectively. Corresponding HRs for exclusive tea drinkers (≥2 cups/d) were 1.16 (1.02-1.32), 1.10 (0.92-1.32) and 1.37 (1.17-1.61). In general, the coffee and tea associations did not differ significantly by sex, race or histologic subtype. Our findings suggest that higher consumption of coffee or tea is associated with increased lung cancer risk. However, these findings should not be assumed to be causal because of the likelihood of residual confounding by smoking, including passive smoking, and change of coffee and tea consumption after study enrolment.

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.

Social Participation and Healthy Aging among the Elderly 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 elderly.

METHODS

This prospective study was conducted in Ohsaki City, Japan, and included 7,226 subjects aged ≥65 years at the baseline survey in 2006. We obtained information on frequency of participation in three types of community activities (i.e. neighborhood activities, hobbies, and volunteer activities) at baseline. Exposure was measured by the number of types of community activities participated in and subjects were categorized into four groups (i.e. none, one type, two types, and three types). The primary outcome was healthy aging as assessed by a questionnaire survey conducted in 2017, and was defined as meeting the following four 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 (ORs) and 95% confidence intervals (95%CIs).

RESULTS

During 11 years of follow-up, 574 (7.9%) subjects attained healthy aging. Compared with subjects not participating in any activity, the multivariable-adjusted ORs (95%CIs) were 1.90 (1.40, 2.59) for those participating in one type, 2.49 (1.84, 3.38) for two types, and 3.06 (2.30, 4.07) for three 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.

Association between Participation in Government Subsidy Program for Domestic Travel and Symptoms Indicative of COVID-19 Infection

Importance

As countermeasures against the economic downturn caused by the coronavirus 2019 (COVID-19) pandemic, many countries have introduced or considering financial incentives for people to engage in economic activities such as travel and use restaurants. Japan has implemented a large-scale, nationwide government-funded program that subsidizes up to 50% of all travel expenses since July 2020 with the aim of reviving the travel industry. However, it remains unknown as to how such provision of government subsidies for travel impacted the COVID-19 pandemic.

Objective

To investigate the association between participation in government subsidies for domestic travel in Japan and the incidence of COVID-19 infections.

Design Setting and Participants

Using the data from a large internet survey conducted between August 25 and September 30, 2020, in Japan, we examined whether individuals who used subsidies experienced a higher likelihood of symptoms indicative of the COVID-19 infection.

Exposure

Participation in the government subsidy program for domestic travel.

Main Outcomes and Measures

Five symptoms indicative of the COVID-19 infection (high fever, sore throat, cough, headache, and smell and taste disorder) within the past one month of the survey.

Results

Of the 25,482 respondents (50.3% [12,809] women; mean [SD] age, 48.4 [17.4] years), 3,289 (12.9%) participated in the subsidy program at the time of survey. After adjusting for potential confounders, we found that participants in the subsidy program exhibited higher incidence of high fever (adjusted rate, 4.8% for participants vs. 3.7% for non-participants; adjusted odds ratio [aOR], 1.90; 95%CI, 1.42-2.54; p<0.001), sore throat (19.8% vs. 11.3%; aOR, 2.09; 95%CI, 1.37-3.20; p=0.002), cough (19.1% vs. 11.2%; aOR 1.96; 95%CI, 1.27-3.02; p=0.007), headache (29.1% vs. 25.5%; aOR, 1.24; 95%CI, 1.07-1.43; p=0.007), and smell and taste disorder (2.6% vs. 1.8%; aOR 1.98; 95%CI; 1.15-3.40; p=0.01) compared with non-participants.

Conclusion and Relevance

The participants of government subsidies for domestic travel experienced a higher incidence of symptoms indicative of the COVID-19 infection.

Effect of a financial incentive (shopping point) on increasing the number of daily walking steps among community-dwelling adults in Japan: a randomised controlled trial

OBJECTIVE

The aim of this study was to investigate the effect of a financial incentive on the number of daily walking steps among community-dwelling adults in Japan.

STUDY DESIGN

Two-arm, parallel-group randomised controlled trial.

SETTING/PARTICIPANTS

We recruited physically inactive community-dwelling adults from Sendai city, Japan. Eligible participants were randomly allocated to an intervention or a wait list control group. Pedometers were used to assess the mean number of daily steps in three periods: baseline (weeks 1-3), intervention (weeks 4-6) and follow-up (weeks 7-9).

INTERVENTION

The intervention group was offered a financial incentive (shopping points) to meet the target number of increased daily steps in the intervention period.

MAIN OUTCOME MEASURES

The primary outcome was an increase in the mean number of daily steps in the intervention and follow-up periods compared with baseline.

RESULTS

Seventy-two participants (69.4% women; mean age, 61.2±16.2 years; mean number of daily steps at baseline, 6364±2804) were randomised to the intervention (n=36) and control groups (n=36). During the intervention period, the increase in mean daily steps was significantly higher in the intervention group (1650, 95% CI=1182 to 2119) than in the control group (514, 95% CI=136 to 891; p<0.001). However, the difference between groups was not significant at follow-up after the incentives were removed (p=0.311). In addition, compared with controls, a significantly higher proportion of participants in the intervention group showed an increase in mean daily steps of ≥1000 (69.4% vs 30.6%, respectively; OR=5.17, 95% CI=1.89 to 14.08). There were no adverse effects from the intervention.

CONCLUSIONS

The present results suggest that financial incentives are effective in promoting short-term increases in physical activity.

TRIAL REGISTRATION NUMBER

UMIN000033276.

Prolonged/delayed cerebral hyperperfusion in adult patients with moyamoya disease with RNF213 gene polymorphism c.14576G>A (rs112735431) after superficial temporal artery-middle cerebral artery anastomosis

OBJECTIVE

Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis is the standard surgical management for moyamoya disease (MMD), whereas cerebral hyperperfusion (CHP) is one of the potential complications of this procedure that can result in delayed intracerebral hemorrhage and/or neurological deterioration. Recent advances in perioperative management in the early postoperative period have significantly reduced the risk of CHP syndrome, but delayed intracerebral hemorrhage and prolonged/delayed CHP are still major clinical issues. The clinical implication of RNF213 gene polymorphism c.14576G>A (rs112735431), a susceptibility variant for MMD, includes early disease onset and a more severe form of MMD, but its significance in perioperative pathology is unknown. Thus, the authors investigated the role of RNF213 polymorphism in perioperative hemodynamics after STA-MCA anastomosis for MMD.

METHODS

Among 96 consecutive adult patients with MMD comprising 105 hemispheres who underwent serial quantitative cerebral blood flow (CBF) analysis by N-isopropyl-p-[123I]iodoamphetamine SPECT after STA-MCA anastomosis, 66 patients consented to genetic analysis of RNF213. Patients were routinely maintained under strict blood pressure control during and after surgery. The local CBF values were quantified at the vascular territory supplied by the bypass on postoperative days (PODs) 1 and 7. The authors defined the radiological CHP phenomenon as a local CBF increase of more than 150% compared with the preoperative values, and then they investigated the correlation between RNF213 polymorphism and the development of CHP.

RESULTS

CHP at POD 1 was observed in 23 hemispheres (23/73 hemispheres [31.5%]), and its incidence was not statistically different between groups (15/41 [36.6%] in RNF213-mutant group vs 8/32 [25.0%] in RNF213-wild type (WT) group; p = 0.321). CHP on POD 7, which is a relatively late period of the CHP phenomenon in MMD, was evident in 9 patients (9/73 hemispheres [12.3%]) after STA-MCA anastomosis. This prolonged/delayed CHP was exclusively observed in the RNF213-mutant group (9/41 [22.0%] in the RNF213-mutant group vs 0/32 [0.0%] in the RNF213-WT group; p = 0.004). Multivariate analysis revealed that RNF213 polymorphism was significantly associated with CBF increase on POD 7 (OR 5.47, 95% CI 1.06-28.35; p = 0.043).

CONCLUSIONS

Prolonged/delayed CHP after revascularization surgery was exclusively found in the RNF213-mutant group. Although the exact mechanism underlying the contribution of RNF213 polymorphism to the prolonged/delayed CBF increase in patients with MMD is unclear, the current study suggests that genetic analysis of RNF213 is useful for predicting the perioperative pathology of patients with MMD.

Education Level, Monthly Per-Capita Expenditure, and Healthy Aging in the Older Indonesian Population: The Indonesia Family Life Survey 2007 and 2014

In developed countries, the relationship between education level, wealth, and healthy aging have been found to be mediated by modifiable risk factors, such as obesity, physical activities, and smoking status. The present study was to investigate the association between education level, monthly per-capita expenditure (PCE), and healthy aging in the older Indonesian population, and to clarify modifiable risk factors that mediate this association. A 7-year prospective longitudinal study (2007-2014) was conducted on 696 older Indonesian individuals (≥ 50 years) living in 13 different provinces in Indonesia during the survey periods. Data on educational level, PCE, and modifiable risk factors were collected in 2007. Information on healthy aging was obtained in both 2007 and 2014. A multivariate-adjusted logistic regression model was used to estimate the odds ratio (ORs) and 95% confidence intervals (CIs) for healthy aging by education level and PCE. The mediating effects were estimated using a four-way effect decomposition. Out of 696 eligible subjects, 206 (29.6%) were judged as healthy aging in 2014. The OR (95% CI) for healthy aging for participants with a higher education level was 1.81 (1.23-2.65) compared with those with a lower education level, and no significant association was observed between PCE and healthy aging. An association was thus observed between education level and healthy aging, but not PCE. Importantly, the association between education level, PCE, and healthy aging does not appear to be mediated by the modifiable risk factors. Priorities in making health policy would be different between developed countries and developing countries.

The impact of risk factors for dementia in China

BRIEF SUMMARY

We evaluated the impact of seven risk factors for dementia in China. Physical inactivity, midlife hypertension and low education are proposed to be the largest fraction contributors to dementia. 55% of dementia were attributable to one or more of the seven risk factors.

BACKGROUND

Previous studies have highlighted the impact of seven risk factors (midlife obesity, physical inactivity, smoking, low education, diabetes mellitus, midlife hypertension and depression) against dementia. However, the impact of these risk factors on dementia has not been evaluated among the Chinese population.

OBJECTIVE

To clarify the impact of seven major risk factors on the incidence of dementia in China.

DESIGN

The prevalence of risk factors was derived from the latest national surveys. Relative risks of corresponding risk factors were derived from the latest cohort or cross-sectional studies.

SETTING AND SUBJECTS

Three national surveys were included in the present study to obtain prevalence data of seven risk factors: the China Chronic Disease and Risk Factor Surveillance Survey (CCDRFSS) (2013), which covered about 170,000 adults (aged ≥18 years) from 31 provinces; (2) China National Survey of Chronic Kidney Disease (CNSCKD) (2010), which covered about 50,000 adults (aged ≥18 years) from 13 provinces; and (3) China Family Panel Studies Survey (CFPSS) (2012), which covered about 30,000 adults (aged ≥18 years) from 25 provinces.

METHODS

Levin's formula was used to calculate the population attributable fraction (PAF) for each risk factor for dementia. The combined PAF of the seven risk factors was calculated assuming the independence of each risk factor.

RESULTS

Physical inactivity (PAF, 24.3%), midlife hypertension (PAF, 22.1%) and low education (PAF: 11.9%) were the top three factors that contributed to dementia. The total PAF of the seven risk factors was 55% in the Chinese population.

CONCLUSIONS

promotion of physical activity, control of hypertension and improvement of nationwide educational level may be helpful public health strategies to decrease the incidence of dementia in China.

Joint impact of common risk factors on incident dementia: A cohort study of the Swedish Twin Registry

BACKGROUND

As common risk factors of dementia, nine factors (low education, hearing loss, obesity, hypertension, smoking, depression, physical inactivity, diabetes and social isolation) were proposed. However, the joint impact of these factors on incident dementia is still uncertain; hence, we aimed to examine this impact.

METHODS

We conducted a cohort study of 9017 cognitively intact individuals aged ≥ 65 years in the Swedish Twin Registry. The main exposure was the total number of reported risk factors (ranging from 0 to 9). Data on dementia diagnoses were based on clinical workup and national health registers. After estimating the adjusted hazard ratios of incident dementia, the population attributable fraction (PAF) was calculated. We then conducted additional analyses, including APOE ε4 status in a genotyped subsample (n = 2810) to check the relative impact of the main exposure and discordant twin pair (n = 1158) analysis to consider confounding by familial effects (shared genetic or familial environmental factors).

RESULTS

The number of dementia cases was 1950 (21.6%). A dose-response relationship between the number of risk factors and incident dementia was observed; hazard ratio (95% confidence interval) per one-unit increment in number of risk factors was 1.07 (1.03 to 1.11). The PAF for the combination of the nine risk factors was 10.4%. The PAF of all nine risk factors was smaller than that of APOE ε4 genotype (20.8%) in the subsample. Discordant pair analysis suggested that the observed association was not likely explained by familial effects.

CONCLUSION

The nine risk factors may have considerable impact as modifiable factors on incident dementia.

Social trust predicts sleep disorder at 6 years after the Great East Japan earthquake: data from a prospective cohort study

Background

The physical and psychological health impacts on victims of the Great East Japan Earthquake (GEJE) have lasted for a long time. Some cross-sectional studies have reported a relationship between social networks and/or social support and mental health among victims. Previous studies were cross-sectional observations at one time point after a disaster, it remains unclear whether the lack of social trust soon after the GEJE predicts long-term mental health outcomes among the victims. The objective of the present study was to examine prospectively the association between social trust soon after the GEJE and trends in sleep disorders up to 6 years after the GEJE.

Methods

We conducted a health survey on residents living in two areas affected by the GEJE. We analyzed data from 1293 adults (aged ≥18 years) who had participated in an initial health survey. The participants responded to a self-administrated questionnaire composed of items on health condition, mental health, including sleep disorders (based on the Athens Insomnia Scale [AIS]), and social trust. We classified the participants into two categories (high or low) based on the level of social trust at the first health survey. A linear mixed model was used to estimate trends in AIS scores in relation to social trust at the first health survey.

Results

The AIS scores of participants in the low social trust group were significantly higher than those in the high social trust group throughout the 6 years after the GEJE (P < 0.01). After adjusting for some covariates, the AIS score estimate for the participants who had low social trust was 1.30 point higher than those for the participants who had high social trust.

Conclusion

Social trust at 3 to 5 months after the GEJE predicted AIS scores at 6 years after the GEJE among victims. This finding suggests that it may be possible to identify people who have a lower potential for mental resilience from disaster damage over the long term. Further, health interventions for this high-risk group could help promote resilience after a disaster.

Quantifying the association of low-intensity and late initiation of tobacco smoking with total and cause-specific mortality in Asia

BACKGROUND

Little is known about the health harms associated with low-intensity smoking in Asians who, on average, smoke fewer cigarettes and start smoking at a later age than their Western counterparts.

METHODS

In this pooled analysis of 738 013 Asians from 16 prospective cohorts, we quantified the associations of low-intensity (<5 cigarettes/day) and late initiation (≥35 years) of smoking with mortality outcomes. HRs and 95% CIs were estimated for each cohort by Cox regression. Cohort-specific HRs were pooled using random-effects meta-analysis.

FINDINGS

During a mean follow-up of 11.3 years, 92 068 deaths were ascertained. Compared with never smokers, current smokers who consumed <5 cigarettes/day or started smoking after age 35 years had a 16%-41% increased risk of all-cause, cardiovascular disease (CVD), respiratory disease mortality and a >twofold risk of lung cancer mortality. Furthermore, current smokers who started smoking after age 35 and smoked <5 cigarettes/day had significantly elevated risks of all-cause (HRs (95% CIs)=1.14 (1.05 to 1.23)), CVD (1.27 (1.08 to 1.49)) and respiratory disease (1.54 (1.17 to 2.01)) mortality. Even smokers who smoked <5 cigarettes/day but quit smoking before the age of 45 years had a 16% elevated risk of all-cause mortality; however, the risk declined further with increasing duration of abstinence.

CONCLUSIONS

Our study showed that smokers who smoked a small number of cigarettes or started smoking later in life also experienced significantly elevated all-cause and major cause-specific mortality but benefited from cessation. There is no safe way to smoke-not smoking is always the best choice.

Association between Adult Height and Risk of Lung Cancer Incidence among Japanese Men: The Miyagi Cohort Study

It is already known that adult height is a factor associated with an increased risk of colon cancer and postmenopausal breast cancer, pancreatic cancer, premenopausal breast cancer, and ovarian cancer. However, the association between adult height and lung cancer incidence remains unclear. The purpose of the present study was to examine the association between adult height and the risk of lung cancer incidence in the Japanese population. We analyzed data for 43,743 men and women who were 40-64 years old at the baseline in 1990. We divided the participants into quintiles based on height at the baseline. Cox proportional hazards analysis was used to estimate the multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) for the incidence of lung cancer according to adult height, after adjustment for potential confounders. We identified 1,101 incident case of lung cancer during 24.5 years of follow-up. The multivariate HRs and 95% CIs for the highest category relative to the lowest were 1.48 (1.15-1.91) in men and 1.35 (0.91-1.99) in women. Furthermore, the association between adult height and the incidence of lung cancer was found the significant increased risk among ever smokers in men, but not never smokers. We also observed that adult height tend to be associated with an increased risk of small cell lung cancer and squamous cell carcinoma. This prospective cohort study has demonstrated a positive association between adult height and the risk of lung cancer incidence among men, especially those who have ever smoked.

Association of serum adiponectin levels and body mass index with worsening depressive symptoms in elderly individuals: a 10-year longitudinal study

Objectives: Data regarding the association between adiponectin levels and body mass index (BMI) and long-term changes in depressive symptoms are limited and inconsistent. Thus, we investigated whether circulating adiponectin levels and BMI were independently and combinedly correlated to longitudinal changes in depressive symptoms.Methods: This prospective cohort study evaluated 269 elderly Japanese individuals aged ≥70 years who participated in the Tsurugaya Project conducted between 2002 and 2012. A short form of the Geriatric Depression Scale (GDS) was used to assess depressive status. Serum adiponectin levels were measured using an enzyme-linked immunosorbent assay or a latex particle-enhanced turbidimetric immunoassay. BMI was calculated as body weight (kg)/height (m²).Results: Multiple linear regression analysis revealed that baseline serum adiponectin levels were positively associated with changes in GDS scores (β = 0.14, P = 0.035). However, no association was observed after adjusting for BMI (β = 0.09, P = 0.185). Low BMI was associated with increased GDS scores at the 10-year follow-up (β = -0.14, P = 0.033). Participants with a combination of high adiponectin levels and low BMI had a 3.3-fold higher risk of worsening depressive symptoms than those with low adiponectin levels and high BMI (odds ratio: 3.35, 95% confidence interval: 1.60-7.00; P = 0.001).Conclusions: This longitudinal study indicated that high serum adiponectin levels and low BMI were both associated with worsening depressive symptoms among older Japanese individuals. Furthermore, the combination of high adiponectin levels and low BMI was associated with worsening depressive symptoms.

Effect of choroidal collateral vessels on de novo hemorrhage in moyamoya disease: analysis of nonhemorrhagic hemispheres in the Japan Adult Moyamoya Trial

OBJECTIVE

Following hemorrhagic stroke in moyamoya disease, de novo intracranial hemorrhage can occur in the previously unaffected nonhemorrhagic hemisphere. In the present analysis the authors intended to determine whether the presence in the nonhemorrhagic hemisphere of choroidal collateral vessels, which have been the focus of attention as a source of bleeding, affects the risk of de novo hemorrhage.

METHODS

The subject of focus of the present cohort study was the nonhemorrhagic hemispheres of adult patients with hemorrhagic moyamoya disease enrolled in the Japan Adult Moyamoya Trial and allocated to the nonsurgical arm. The variable of interest was the presence of choroidal collaterals (also termed choroidal anastomoses), identified with baseline angiography and represented by a connection (anastomosis) between the anterior or posterior choroidal arteries and the medullary arteries. The outcome measure was de novo hemorrhage during the 5-year follow-up period, assessed in all nonhemorrhagic hemispheres. The incidence of de novo hemorrhage in the collateral-positive and -negative groups was compared.

RESULTS

Choroidal collaterals were present in 15 of 36 (41.7%) nonhemorrhagic hemispheres analyzed. The overall annual risk of de novo hemorrhage was 2.0%. Three de novo hemorrhages occurred in the collateral-positive group, whereas no hemorrhage occurred in the collateral-negative group. The annual risk of de novo hemorrhage was significantly higher in the collateral-positive group than in the collateral-negative group (5.8% per year vs 0% per year; p = 0.017). All hemorrhage sites corresponded to the distribution of choroidal collaterals.

CONCLUSIONS

The present preliminary results suggest that the presence of choroidal collaterals affects the risk of de novo hemorrhage in the nonhemorrhagic hemisphere, subject to verification in larger studies. Further studies are needed to determine the optimal treatment strategy for nonhemorrhagic hemispheres and asymptomatic patients.

Impact of cortical hemodynamic failure on both subsequent hemorrhagic stroke and effect of bypass surgery in hemorrhagic moyamoya disease: a supplementary analysis of the Japan Adult Moyamoya Trial

OBJECTIVE

Here, the authors aimed to determine whether the presence of cerebral hemodynamic failure predicts subsequent bleeding attacks and how it correlates with the effect of direct bypass surgery in hemorrhagic moyamoya disease.

METHODS

Data from the Japanese Adult Moyamoya (JAM) Trial were used in this study: 158 hemispheres in 79 patients. A newly formed expert panel evaluated the SPECT results submitted at trial enrollment and classified the cortical hemodynamic state of the middle cerebral artery territory of each hemisphere into one of the following three groups: SPECT stage (SS) 0 as normal, SS1 as decreased cerebrovascular reserve (CVR), and SS2 as decreased CVR with decreased baseline blood flow. In the nonsurgical cohort of the JAM Trial, the subsequent hemorrhage rate during the 5-year follow-up was compared between the SS0 (hemodynamic failure negative) and SS1+2 (hemodynamic failure positive) groups. The effect of direct or combined direct/indirect bypass surgery on hemorrhage prevention was examined in each subgroup.

RESULTS

The hemodynamic grade was SS0 in 59 (37.3%) hemispheres, SS1 in 87 (55.1%), and SS2 in 12 (7.6%). In the nonsurgical cohort, subsequent hemorrhage rates in the SS0 and SS1+2 groups were 12 cases per 1000 person-years and 67 cases per 1000 person-years, respectively. Kaplan-Meier analysis revealed that hemorrhagic events were significantly more common in the SS1+2 group (p = 0.019, log-rank test). Cox regression analysis showed that hemodynamic failure was an independent risk factor for subsequent hemorrhage (HR 5.37, 95% CI 1.07-27.02). In the SS1+2 subgroup, bypass surgery significantly suppressed hemorrhagic events during 5 years (p = 0.001, HR 0.16, 95% CI 0.04-0.57), with no significant effect in the SS0 group (p = 0.655, HR 1.56, 95% CI 0.22-11.10). Examination of effect modification revealed that the effect of surgery tended to differ nonsignificantly between these two subgroups (p = 0.056).

CONCLUSIONS

Hemodynamic failure is an independent risk factor for subsequent hemorrhage in hemorrhagic moyamoya disease. Direct bypass surgery showed a significant preventive effect in the hemodynamically impaired hemispheres. Thus, hemodynamic failure, as well as previously proposed factors such as choroidal anastomosis, should be considered for the surgical indication in hemorrhagic moyamoya disease.Clinical trial registration no.: C000000166 (umin.ac.jp).

[Current status and issues around the process of health promotion program implementation by the municipal office of health and welfare: Survey results of all municipalities of six prefectures]

Objectives We aimed to investigate the progress of health promotion program implementation. This included an examination of the current status of and issues around planning, implementation, and evaluation of health and welfare services at the municipal level; further progress through focus on the population approach emphasized in Health Japan 21 (2nd) was also discussed.Methods A questionnaire survey on health promotion and welfare services was conducted among municipal offices in charge of health promotion. The status of health promotion program implementation was classified by types and fields. For focused health and welfare services, respondents were asked to answer a self-administered questionnaire about the process of planning, implementation, and evaluation. The details of services were confirmed by browsing reference materials or website information. We distributed the questionnaires to all 260 municipalities of 6 prefectures (Miyagi, Saitama, Shizuoka, Aichi, Osaka, and Wakayama); of which, 238 municipalities responded (response rate: 91.5%).Results Health promotion programs on nutrition and diet, physical activity, dental and oral health, prevention of lifestyle-related diseases, and promotion of regular health checkups were implemented with a high rate. Among the 238 municipalities, 85.2% responded that they focused on educational activities targeting the general population; of which 27.4% were considering using incentives to promote greater health awareness. Our survey indicated that 14.8% of municipalities focused on health education and classroom-style programs. While planning programs, 52.1% of municipalities used "materials from other municipalities where such programs were already implemented" and 89.1% of municipalities used them in incentive-related programs. Although 70% of municipalities were aware of health discrepancies among the local population, approximately 90% did not consider discrepancies between different economic, living environment, and occupation groups when planning programs. Although 87.3% of municipalities used number of participants as the main indicator in evaluating the programs, approximately 30% of municipalities used coverage rate and before-and-after assessments of health conditions as the main indicators.Conclusion Findings from this study suggest that improvements in the process of health promotion program planning and implementation, reference materials, and the perspective of health discrepancies are needed, along with an evaluation in programs focusing both on educational activities targeting the general population and incentive-related programs. It is also recommended that the central government and prefectures should not only introduce precedents, but also provide information. Using this, municipalities can demonstrate applied skills, such as the rationale and preparation status of the program, and propose evaluations based on the plan-do-check-act cycle.

Emotional support (giving or receiving) and risk of incident dementia: The Ohsaki Cohort 2006 Study

Previous studies have suggested that emotional support may promote cognition; however, the effects of giving or receiving emotional support on incident dementia remain unclear. Therefore, we sought to investigate the relationship between emotional support (giving or receiving) and incident dementia. In December 2006, we conducted a prospective cohort study of 31,694 Japanese individuals aged ≥65 years who lived in Ohsaki City, Miyagi Prefecture, Japan. A self-reported questionnaire including items on emotional support and lifestyle factors was distributed. After excluding those who did not provide consent or responses to all items, 13,636 eligible responses were analyzed for this study. According to responses of "yes" or "no" for emotional support, we made two categories for both giving (gave or did not give) and receiving (received or did not receive) emotional support. Furthermore, we combined giving and receiving emotional support into four categories ("giving = no & receiving = no", "giving = no & receiving = yes", "giving = yes & receiving = no", "giving = yes & receiving = yes"). Data on incident dementia were retrieved from the Long-term Care Insurance Database in which participants were followed up for 5.7 years. Using multivariate Cox proportional hazards models, we found that compared with participants who did not give emotional support to others, those who did give had a lower risk of dementia (multivariate-adjusted hazard ratio [HR]: 0.61 (95% confidence interval [CI]: 0.52, 0.71)). However, a nonsignificant relationship was observed for receiving emotional support. Additionally, compared to "giving = no & receiving = no" for emotional support, "giving = no & receiving = yes" showed a higher risk of dementia (multivariate-adjusted HR: 1.51 [95% CI: 1.07, 2.14]).

Polyunsaturated fatty acids and risk of Alzheimer's disease: a Mendelian randomization study

Purpose

Observational studies have suggested that polyunsaturated fatty acids (PUFAs) may decrease Alzheimer’s disease (AD) risk. In the present study, we examined this hypothesis using a Mendelian randomization analysis.

Methods

We used summary statistics data for single-nucleotide polymorphisms associated with plasma levels of 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 AD from a genome-wide association meta-analysis of 63,926 individuals (21,982 diagnosed AD cases, 41,944 controls).

Results

None of the genetically predicted PUFAs was significantly associated with AD risk; odds ratios (95% confidence interval) per 1 SD increase in PUFA levels were 0.98 (0.93, 1.03) for linoleic acid, 1.01 (0.98, 1.05) for arachidonic acid, 0.96 (0.88, 1.06) for alpha-linolenic acid, 1.03 (0.93, 1.13) for eicosapentaenoic acid, 1.03 (0.97, 1.09) for docosapentaenoic acid, and 1.01 (0.81, 1.25) for docosahexaenoic acid.

Conclusions

This study did not support the hypothesis that PUFAs decrease AD risk.

Electronic supplementary material

The online version of this article (10.1007/s00394-019-02126-x) contains supplementary material, which is available to authorized users.

Association of BMI, Smoking, and Alcohol with Multiple Myeloma Mortality in Asians: A Pooled Analysis of More than 800,000 Participants in the Asia Cohort Consortium

BACKGROUND

To date, few epidemiologic studies have been conducted to elucidate lifestyle-related risk factors for multiple myeloma in Asia. We investigated the association of body mass index (BMI), smoking, and alcohol intake with the risk of multiple myeloma mortality through a pooled analysis of more than 800,000 participants in the Asia Cohort Consortium.

METHODS

The analysis included 805,309 participants contributing 10,221,623 person-years of accumulated follow-up across Asia Cohort Consortium cohorts. HRs and 95% confidence intervals (95% CI) for the association between BMI, smoking, and alcohol at baseline and the risk of multiple myeloma mortality were assessed using a Cox proportional hazards model with shared frailty.

RESULTS

We observed a statistically significant dose-dependent association between BMI categories and the risk of multiple myeloma mortality (<18.5 kg/m2: HR = 0.80, 95% CI: 0.52-1.24; 18.5-24.9 kg/m2: reference; 25.0-29.9 kg/m2: HR = 1.17, 95% CI: 0.94-1.47; ≥30 kg/m2: HR = 1.61, 95% CI: 0.99-2.64, P trend = 0.014). By sex, this association was more apparent in women than in men (P for heterogeneity between sexes = 0.150). We observed no significant associations between smoking or alcohol consumption and risk of multiple myeloma mortality.

CONCLUSIONS

This study showed that excess body mass is associated with an increased risk of multiple myeloma mortality among Asian populations. In contrast, our results do not support an association between smoking or alcohol consumption and the risk of multiple myeloma mortality in Asian populations.

IMPACT

This study provides important evidence on the association of BMI, smoking, and alcohol with the risk of multiple myeloma mortality in Asian populations.

Association between improved adherence to the Japanese diet and incident functional disability in older people: The Ohsaki Cohort 2006 Study

BACKGROUND & AIMS

Although it has been reported that the Japanese dietary pattern is associated with a lower risk of incident functional disability among older people, the potential benefits of improving adherence to the Japanese diet remain unclear. The aim of the present study was to evaluate the association between 12-year change in adherence to the Japanese diet and the subsequent risk of incident functional disability in older people in Japan.

METHODS

We analyzed 10-year follow-up data from a cohort study of 2923 Japanese older adults (age ≥65 years) in 2006. We collected dietary information using a validated 39-item food frequency questionnaire at two time points (1994 and 2006). Adherence to the Japanese diet (high intake of rice, miso soup, seaweeds, pickles, green and yellow vegetables, fish, green tea; low intake of beef and pork, and coffee) was assessed using the Japanese Diet Index (JDI), which ranges from 0 to 9. Participants were categorized into five groups according to changes in the JDI score at these two time points. Data on incident functional disability from December 2006 to November 2016 were retrieved from the public long-term care insurance database. The Cox proportional hazards model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for incident functional disability.

RESULTS

During 22,466 person-years of follow-up, 1093 cases of incident functional disability were documented. Compared with participants in the group with the largest decrease in the JDI score (≤-2), the multivariate-adjusted HR (95% CI) of incident functional disability was 0.77 (0.61-0.98) for those in the largest increase group (≥+2).

CONCLUSIONS

Improved adherence to the Japanese diet was associated with a significantly lower risk of incident functional disability in older people in Japan.

The association between bilateral maximum occlusal force and all-cause mortality among community-dwelling older adults: The Tsurugaya project

PURPOSE

This study aimed to investigate the relationship between the bilateral maximum occlusal force (MOF) of full dental arches and all-cause mortality in a group of community-dwelling older males and females in Japan.

METHODS

This 13-year prospective cohort study was conducted among 815 older adults (395 male and 420 female) aged 70 years or over (mean age ± standard deviation: 75.1 ± 4.5 years). Bilateral MOF in the intercuspal position was recorded with horseshoe-shaped pressure-sensitive film. Participants were grouped by gender into tertiles according to MOF. Demographic variables, chronicity, comorbidity, physical status, cognitive and psychological status, social functioning, and blood chemistry data were also assessed. Information regarding all-cause mortality and migration was obtained from the Sendai Municipal Authority. Cox proportional hazard modeling was performed to assess all-cause mortality during the follow-up period.

RESULTS

In total, 159 male and 109 female participants died over a median 12.9-year follow-up period, and the cumulative mortality significantly increased with lower MOF in both males and females. The multivariate Cox proportional hazard model demonstrated a significant increase in the risk of all-cause mortality associated with lower tertiles of MOF, relative to the upper tertile in males (hazard ratio: 1.62; 95% confidence interval: 1.05-2.51) and females (hazard ratio: 1.94; 95% confidence interval: 1.10-3.56).

CONCLUSIONS

There was a significant and independent association of bilateral MOF with all-cause mortality in community-dwelling elderly males and females in Japan. These findings suggested that maintenance of oral functioning contributes to general health.

Mushroom consumption and incident risk of prostate cancer in Japan: A pooled analysis of the Miyagi Cohort Study and the Ohsaki Cohort Study

In vivo and in vitro evidence has shown that mushrooms have the potential to prevent prostate cancer. However, the relationship between mushroom consumption and incident prostate cancer in humans has never been investigated. In the present study, a total of 36,499 men, aged 40–79 years, who participated in the Miyagi Cohort Study in 1990 and in the Ohsaki Cohort Study in 1994 were followed for a median of 13.2 years. Data on mushroom consumption (categorized as <1, 1–2 and ≥3 times/week) was collected using a validated food frequency questionnaire. Cox proportional hazards regression analysis was used to estimate multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) for prostate cancer incidence. During 574,397 person‐years of follow‐up, 1,204 (3.3%) cases of prostate cancer were identified. Compared to participants with mushroom consumption <1 time/week, frequent mushroom intake was associated with a decreased risk of prostate cancer (1–2 times/week: HRs [95% CIs] = 0.92 [0.81, 1.05]; ≥3 times/week: HRs [95% CIs] = 0.83 [0.70, 0.98]; p‐trend = 0.023). This inverse relationship was especially obvious among participants aged ≥50 years and did not differ by clinical stage of cancer and intake of vegetables, fruit, meat and dairy products. The present study showed an inverse relationship between mushroom consumption and incident prostate cancer among middle‐aged and elderly Japanese men, suggesting that habitual mushroom intake might help to prevent prostate cancer.

What's new?

Mushrooms have long been used as a source of food and medicine in Asian cultures and are suspected of possessing anticancer properties. Whether the consumption of mushrooms can help prevent cancer, however, remains unknown. In the present study, among men who enrolled in the Miyagi and Ohsaki cohort studies in Japan in 1990 and 1994, respectively, long‐term follow‐up indicates that frequent mushroom consumption is associated with reduced prostate cancer risk. The effect was especially pronounced in men age 50 or older and in those with relatively low in fruit and vegetable intake and high in meat and dairy intake.

Association between educational level and total and cause-specific mortality: a pooled analysis of over 694 000 individuals in the Asia Cohort Consortium

OBJECTIVE

To study the association of educational level and risk of death from all causes, cardiovascular disease (CVD) and cancer among Asian populations.

DESIGN

A pooled analysis of 15 population-based cohort studies.

SETTING AND PARTICIPANTS

694 434 Asian individuals from 15 prospective cohorts within the Asia Cohort Consortium.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

HRs and 95% CIs for all-cause mortality, as well as for CVD-specific mortality and cancer-specific mortality.

RESULTS

A total of 694 434 participants (mean age at baseline=53.2 years) were included in the analysis. During a mean follow-up period of 12.5 years, 103 023 deaths were observed, among which 33 939 were due to cancer and 34 645 were due to CVD. Higher educational levels were significantly associated with lower risk of death from all causes compared with a low educational level (≤primary education); HRs and 95% CIs for secondary education, trade/technical education and ≥university education were 0.88 (0.85 to 0.92), 0.81 (0.73 to 0.90) and 0.71 (0.63 to 0.80), respectively (ptrend=0.002). Similarly, HRs (95% CIs) were 0.93 (0.89 to 0.97), 0.86 (0.78 to 0.94) and 0.81 (0.73 to 0.89) for cancer death, and 0.88 (0.83 to 0.93), 0.77 (0.66 to 0.91) and 0.67 (0.58 to 0.77) for CVD death with increasing levels of education (both ptrend <0.01). The pattern of the association among East Asians and South Asians was similar compared with ≤primary education; HR (95% CI) for all-cause mortality associated with ≥university education was 0.72 (0.63 to 0.81) among 539 724 East Asians (Chinese, Japanese and Korean) and 0.61 (0.54 to 0.69) among 154 710 South Asians (Indians and Bangladeshis).

CONCLUSION

Higher educational level was associated with substantially lower risk of death among Asian populations.

Preventive Effect of Oral Self-Care on Pneumonia Death among the Elderly with Tooth Loss: The Ohsaki Cohort 2006 Study

Tooth loss is a risk factor for pneumonia mortality, but it is unclear whether oral care negates excess mortality due to pneumonia among community-dwelling elderly with tooth loss. The purpose of this study was to examine the influence of oral care on the association between the number of remaining teeth and the risk of pneumonia death. We analyzed for 18,098 individuals (aged ≥ 65 years) participating in a prospective cohort study. In a 2006 baseline survey, the following data were collected: the number of remaining teeth, oral care, history of disease, smoking, alcohol drinking, education level and so forth. We also obtained data on dates and causes of death between 2006 and 2014. The primary outcome was mortality due to pneumonia. Compared with those having ≥ 20 teeth, the risk of pneumonia mortality was increased among participants having 10-19 or 0-9 teeth; the multivariate hazard ratios (HRs) (95% confidence intervals [CI]) were 1.45 (1.03-2.04) and 1.38 (1.01-1.87), respectively. Among those having 0-9 teeth, a significantly increased risk of mortality due to pneumonia was disappeared for those who brushed their teeth ≥ 2 times per day, for those with visiting a dentist, and for those with use of denture, whereas the risk persisted among those who brushed their teeth ≤ 2 times per day, for those without visiting a dentist, and for those without use of denture. Tooth-brushing, visiting a dentist or use of denture may negate the increased risk of pneumonia death among the elderly with tooth loss.

A cross-sectional study of the associations between the traditional Japanese diet and nutrient intakes: the NILS-LSA project

Background

Although our previous study using a food frequency questionnaire simulated nutritional characteristics of the traditional Japanese diet, this issue has not been sufficiently evaluated. This study was conducted to examine the relationship between the traditional Japanese diet and nutrient density (ND).

Methods

A cross-sectional study employing the dietary record method was conducted among 2221 community-dwelling Japanese adults (40–88 years) living in Aichi Prefecture, Japan, in 2006–2008. Based on previous studies, a 9-component Japanese Diet Index (JDI) and a 12-component modified JDI (mJDI₁₂) were defined. To develop a new weighted index, a multiple linear regression model was used to select food components which were significantly associated with an ND score (integrated by 11 nutrient components) from the mJDI₁₂ and weight them. Correlation analyses were performed between JDI, mJDI₁₂, the new weighted JDI score and the ND score and its 11 nutrient components. The findings were validated with data from 2008 to 2010 by assessing the associations between the JDIs scores and the ND score.

Results

Scores of the JDI and mJDI₁₂ were positively correlated with the ND score (corresponding Spearman’s ρ [95% confidence interval; CI], 0.34 [0.31, 0.38] and 0.44 [0.41, 0.48], respectively; P < 0.05 for both). Among the mJDI₁₂, 9 food components (rice, fish and shellfish, green and yellow vegetables, seaweed, green tea, beef and pork, soybeans and soybean foods, fruit, and mushrooms) significantly associated with the ND score. All of these 9 components were weighted and a new weighted JDI (wJDI₉) was developed. The wJDI₉ score was also positively correlated with the ND score (Spearman’s ρ [95% CI] = 0.61 [0.58, 0.64]; P < 0.05). However, scores for all 3 indices were positively correlated with sodium intake. The wJDI₉ score obtained using dietary record data from 2008 to 2010 was also positively correlated with the ND score (Spearman’s ρ [95% CI] = 0.61 [0.58, 0.64]; P < 0.05).

Conclusions-

Adhering to a traditional Japanese diet as defined by the JDI was associated with good ND. Furthermore, the modified indices (mJDI₁₂ and wJDI₉) had a higher performance for ND. However, all of the indices were correlated with high sodium intake.

Electronic supplementary material

The online version of this article (10.1186/s12937-019-0468-9) contains supplementary material, which is available to authorized users.

The Japanese Dietary Pattern Is Associated with Longer Disability-Free Survival Time in the General Elderly Population in the Ohsaki Cohort 2006 Study

BACKGROUND

Epidemiologic observations have raised expectations that the Japanese dietary pattern could promote longer disability-free survival (DFS) times among the Japanese population; however, no previous study has examined this issue.

OBJECTIVE

The aim of this study was to investigate the association between the Japanese dietary pattern and DFS time in the elderly Japanese population.

METHODS

We analyzed follow-up data covering a 10-y period for 9456 elderly Japanese individuals (aged ≥65 y) participating in a community-based prospective cohort study. Dietary habits were assessed using a food-frequency questionnaire. Based on previous studies, we used 9 food items to calculate the Japanese Diet Index (JDI) score: rice, miso soup, fish and shellfish, green and yellow vegetables, seaweed, pickled vegetables, green tea (1 point for each item if the consumption value was more than or equal to the median, and 0 points otherwise), beef and pork, and coffee (0 points for each item if the consumption value was more than or equal to the median, and 1 point otherwise). Differences in median age at incident disability or death [50th percentile differences (PDs)] according to quartiles (Q1-Q4) of the JDI score were estimated using Laplace regression.

RESULTS

During the follow-up period, 4233 (44.8%) incident disability or death events occurred. In addition, a higher JDI score was significantly associated with longer DFS time: compared with the lowest quartile of JDI scores (Q1), the multivariate-adjusted 50th PD (95% CI) was 7.1 (1.8, 12.4) mo longer for Q4. Each 1-SD increase of the JDI score was associated with 3.7 (1.7, 5.7) additional months of life without disability (P-trend < 0.01). No differences were seen in sex or chronic condition (no or ≥1 chronic condition) at baseline. A post hoc analysis showed a larger effect on DFS time when using a modified JDI score without coffee.

CONCLUSION

These results suggest that the Japanese dietary pattern is associated with improved DFS time in the general elderly population.

The association between emotional and instrumental social support and risk of suicide death: A population-based cohort study

Suicide is an important public health issue and previous studies have suggested that social support can one preventive factor. However, the association between emotional and instrumental social support and suicide death has not been investigated in detail. The purpose of this study was to investigate the association between each type of social support and suicide death based on a population-based cohort study. We analyzed follow-up data for 47,223 subjects (aged ≥40 y) participating in a community-based, prospective cohort study. At the baseline, the subjects were asked five questions about social support. The end point of the study was suicide mortality, based on data from the National Vital Statistics. The Cox model was used to estimate the multivariate-adjusted hazard ratios of suicide death. In addition, stratified analysis was conducted to test the interaction of each type of social support with gender (male/female) and age (<65/≥65 y) separately. Among 320,880 person-years of follow-up, 90 cases of suicide death were documented. There were significant association between instrumental social support and lower risk of suicide death, and the hazard ratio was 0.60 (95% CI: 0.38-0.94). Emotional social support was also associated with a lower risk of suicide death, but not to a significant degree, and the hazard ratio was 0.70 (95% CI: 0.42-1.17). It is suggested that instrumental social support was significantly associated with a lower risk of suicide death, and emotional social support tended to be associated with a lower risk of suicide death.

Abstract 632: Associations of coffee and tea consumption with lung cancer risk: A pooled analysis of 17 cohort studies involving over 1.2 million participants

Background

Epidemiological studies investigating the associations of coffee and tea intake with lung cancer risk have yielded inconsistent results. These previous studies included mostly lung cancer patients diagnosed among smokers. Because coffee and tea consumption are closely related to smoking behavior, these previous studies could suffer from biases due to residual confounding of smoking. To better characterize the relationship, a large study with a large number of lung cancer cases diagnosed among never smokers and detailed information on tea and coffee consumption, is needed. Using data from a large-scale pooled analysis that consists of over 1.2 million participants in the U.S. and Asia, we carried out a comprehensive evaluation on the association of coffee and tea intake with lung cancer risk.

Methods

Individual-level data from seven prospective cohort studies conducted in the U.S., and ten studies conducted in Asia, were included. Demographic, lifestyle, coffee and tea intake data were collected at the baseline survey for each study. Multivariable-adjusted Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). The first 2 years of follow-up time was excluded to minimize potential influence of reverse causality on study results. Subgroup analyses by smoking status, sex, race, histologic subtype and coffee type (caffeinated or decaffeinated) were also conducted to assess potential effect modification, as well as heterogeneity of the association.

Results

After a median follow-up of 8.6 years, 20,519 incident lung cancer cases were identified. Both coffee and tea consumption were associated with an increased risk of lung cancer. Comparing non-coffee and non-tea consumption, HRs for lung cancer associated with exclusive coffee drinkers (≥2 cups/day) among current, former and never smokers were 1.30 (95% CI, 1.15-1.47), 1.49 (1.27-1.74) and 1.41 (95% CI, 1.21-1.63), respectively. Similar positive associations were observed for caffeinated and decaffeinated coffee. The HRs associated with exclusive tea drinkers (&gt;2 cups/day) were 1.16 (95% CI, 1.02-1.32), 1.10 (0.92, 1.32) and 1.37 (95% CI, 1.17-1.60) for current, former and never smokers, respectively. These associations did not differ significantly by sex, race or histologic subtypes.

Conclusion

A high consumption of coffee or tea was both associated with an increased risk of lung cancer regardless of race or smoking status. Our study included a large number of never-smoker lung cancer patients, which minimized potential confounding effects due to smoking. The positive association observed for both caffeinated and decaffeinated coffee suggests that compounds other than caffeine may play a role in the etiology of lung cancer.

Citation Format: Jingjing Zhu, Wei Zheng, Rashimi Sinha, Stephanie A. Smith-Warner, Yong-Bing Xiang, Yikyung Park, Shoichiro Tsugane, Emily White, Woon-Puay Koh, Sue K. Park, Norie Sawada, Seiki Kanemura, Yumi Sugawara, Ichiro Tsuji, Kim Robien, Yasutake Tomata, Keun-Young Yoo, Jeongseon Kim, Jian-Min Yuan, Yu-Tang Gao, Yumie Takata, Eiko Saito, William Blot, Xiao-Ou Shu. Associations of coffee and tea consumption with lung cancer risk: A pooled analysis of 17 cohort studies involving over 1.2 million participants [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 632.

Spouse's functional disability and mortality: The Ohsaki Cohort 2006 Study

Aim

Caregiver burden is known to negatively affect a partner's health. Given the important role of physical and mental stress in mortality, a higher caregiver burden might be associated with an increased incidence of fatal events. However, previous studies of the effects of the partner's caregiving on mortality have shown inconsistent results. Thus, the purpose of the present longitudinal study was to determine if there is an association between a spouse's functional disability and mortality in the older Japanese population.

Methods

A baseline survey was carried out with 7598 participants in 2006. Information on the date of functional disability, death or emigration was retrieved from the Ohsaki City government. Functional disability was defined as receiving a certification for long‐term care insurance in Japan. After a follow‐up period of a maximum of 87 months, 1316 of the participants died and Cox regression analysis with adjustment for confounding factors was used to assess mortality after the incidence of functional disability in a spouse.

Results

The multivariate adjusted hazard ratio for mortality was 1.78 (95% confidence interval 1.52–2.08, P < 0.01) in those whose spouses had functional disabilities compared with those with spouses who did not have functional disabilities. The mortality was consistently higher, irrespective of age group or sex.

Conclusions

These results imply that caregiver burden might increase stress responses and lead to increased mortality; therefore, enhancement of support systems, including long‐term care, housing and livelihood support services, for those with disability and their spouses might be important for preventing deaths. Geriatr Gerontol Int 2019; 19: 774–779.

Randomised controlled trial of a financial incentive for increasing the number of daily walking steps: study protocol

INTRODUCTION

Physical activity is one of the major modifiable factors for promotion of public health. Although it has been reported that financial incentives would be effective for promoting health behaviours such as smoking cessation or attendance for cancer screening, few randomised controlled trials (RCTs) have examined the effect of financial incentives for increasing the number of daily steps among individuals in a community setting. The aim of this study is to investigate the effects of financial incentives for increasing the number of daily steps among community-dwelling adults in Japan.

METHODS AND ANALYSIS

This study will be a two-arm, parallel-group RCT. We will recruit community-dwelling adults who are physically inactive in a suburban area (Nakayama) of Sendai city, Japan, using leaflets and posters. Participants that meet the inclusion criteria will be randomly allocated to an intervention group or a waitlist control group. The intervention group will be offered a financial incentive (a chance to get shopping points) if participants increase their daily steps from their baseline. The primary outcome will be the average increase in the number of daily steps (at 4-6 weeks and 7-9 weeks) relative to the average number of daily steps at the baseline (1-3 weeks). For the sample size calculation, we assumed that the difference of primary outcome would be 1302 steps.

ETHICS AND DISSEMINATION

This study has been ethically approved by the research ethics committee of Tohoku University Graduate School of Medicine, Japan (No. 2018-1-171). The results will be submitted and published in a peer-reviewed scientific journal.

TRIAL REGISTRATION NUMBER

UMIN000033276; Pre-results.

Abdominal Fat in Individuals with Overweight Reduced by Consumption of a 1975 Japanese Diet: A Randomized Controlled Trial

OBJECTIVE

This study aimed to investigate whether the intake of the 1975 Japanese diet (JD) could reduce the amount of abdominal fat in people with overweight.

METHODS

Using a single-blind randomized controlled trial, the modern diet (MD) was compared with the 1975-type JD, which is based on the MD but includes five characteristics of the 1975 JD in an enhanced form. Overweight people were randomly assigned to an MD group (n = 30) and a JD group (n = 30). The participants consumed test diets that were provided three times a day for 28 days. Body composition measurements and blood biochemical examinations were performed before and after the test diet intake, and the proportions of change were compared.

RESULTS

Those in the JD group had significantly decreased BMI, fat mass, and levels of low-density lipoprotein cholesterol, glycated hemoglobin, and C-reactive protein (P = 0.002, 0.015, 0.014, 0.012, and 0.039, respectively) and significantly increased high-density lipoprotein cholesterol levels compared with those in the MD group (P = 0.020).

CONCLUSIONS

The intake of a diet with the characteristics of the 1975 JD may have beneficial effects on lipid metabolism in people with overweight and reduce the onset risk of metabolism-related disorders, such as obesity and diabetes.