The Inverse Association between the Frequency of Forest Walking (Shinrin-yoku) and the Prevalence of Insomnia Symptoms in the General Japanese Population: A Japan Multi-Institutional Collaborative Cohort Daiko Study.

Since a single forest walk (Shinrin-yoku or forest bathing) session is reported to improve sleep temporarily, occasional forest walks may have a positive effect on daily sleep. Therefore, this study aimed to examine whether more frequent forest walking is associated with better daily sleep conditions. Data from the second survey of the Japan Multi-Institutional Collaborative Cohort (J-MICC) Daiko Study conducted among residents of Nagoya City, Japan, were used. The study design was a cross-sectional study. In total, 2044 participants (529 men and 1515 women; age, mean ± standard deviation: 58.8 ± 9.9 years) were included in the analysis. Frequent forest walks were associated with a low percentage of insomnia symptoms (Insomnia Severity Index ≥10) in women, but not in men. The adjusted odds ratio for the group that rarely took forest walks with reference to the group that engaged in the activity once a month or more often was 2.04 (95% confidence interval: 1.29-3.23) in women. Forest walk frequency was not significantly associated with sleep duration or sleep efficiency as measured by actigraphy in either men or women. In conclusion, the results suggested that increasing the frequency of forest walks or Shinrin-yoku may be effective in preventing insomnia in women.

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

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

Comparison of Gastric Cancer Risk Classifications Using Conventional and New Pepsinogen Criteria.

Background: New serum pepsinogen (PG) criteria have been shown to indicate more accurately infection with Helicobacter pylori (H. pylori). We sought to improve risk classification for gastric cancer by adopting the new PG criteria with the addition of an H. pylori antibody test. Methods: The study participants were 275 patients with gastric cancer and 275 apparently healthy controls from case-control study data. We cross-sectionally compared the results of gastric cancer risk classifications that were based on a combination of the new PG criteria (PG II ≥ 10 ng/mL or PG I/II ≤ 5) and an H. pylori antibody test with those that were based on a combination of the conventional criteria (PG I ≤ 70 ng/mL and PG I/PG II ≤ 3) and an H. pylori antibody test. Results: Applying the conventional criteria resulted in 89 controls being classified as low risk. Applying the new criteria resulted in 23 controls (bootstrapped 95% confidence intervals [CI]: 14, 32) being additionally classified as high risk. Eight patients with gastric cancer were classified as low risk using the conventional criteria; however, six of these patients were classified as high risk by the new criteria (bootstrapped 95% CI: 2, 11). Conclusions: Compared with the conventional criteria, the new PG criteria with H. pylori antibody reduced instances of gastric cancer cases being misclassified as low risk. These findings suggest that the new PG criteria may help identify individuals at high risk of developing gastric cancer.

Anti-Helicobacter pylori antibody status is associated with cancer mortality: A longitudinal analysis from the Japanese DAIKO prospective cohort study.

Paradoxically, patients with advanced stomach cancer who are Helicobacter pylori-positive (HP+) have a higher survival rate than those who are HP-. This finding suggests that HP infection has beneficial effects for cancer treatment. The present study examines whether HP+ individuals have a lower likelihood of death from cancer than those who are HP-. Prospective cohort data (n = 4,982 subjects enrolled in the DAIKO study between 2008-2010) were used to assess whether anti-HP antibody status was associated with cancer incidence. The median age in the primary registry was 53 years-old (range 35-69 years-old). Over the 8-year observation period there were 234 (4.7%) cancer cases in the cohort and 88 (1.8%) all-cause deaths. Urine anti-HP antibody data was available for all but one participant (n = 4,981; 99.98%). The number of HP+ and HP- individuals was 1,825 (37%) and 3,156 (63%), respectively. Anti-HP antibody distribution per birth year revealed that earlier birth year was associated with higher HP+ rates. With a birth year-matched cohort (n = 3,376), all-cancer incidence was significantly higher in HP+ individuals than those who were HP- (p = 0.00328), whereas there was no significant difference in the cancer death rate between HP+ and HP- individuals (p = 0.888). Cox regression analysis for prognostic factors revealed that the hazards ratio of HP+ was 1.59-fold (95%CI 1.17-2.26) higher than HP- in all-cancer incidence. Potential systemic effects of HP+ status may contribute to reduced likelihood of death for patients after an initial diagnosis of cancer.

Associations between cigarette smoking and biliary tract cancer by anatomic subsite and sex: a prospective cohort study in Japan.

PURPOSE: Biliary tract cancer (BTC) has not been considered a tobacco-related cancer, largely because of inconclusive results from epidemiological studies. We herein evaluate the association between cigarette smoking and risk of death from BTC by anatomic subsite and sex using data from a large, prospective cohort study in Japan. METHODS: The present study included 97,030 Japanese individuals who were enrolled in 1988-1990 and followed until 31 December 2009. Cox proportional hazards regression models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for the association of BTC with cigarette smoking, including smoking status, number of cigarettes smoked per day, and pack-years of smoking. RESULTS: During a mean follow-up of 16.2 years, we documented 484 deaths (187 from gallbladder cancers and 297 from cancers of other and unspecified biliary tract parts). After adjustment for sex, age, body mass index, alcohol consumption, and history of gallstones, current smokers had a higher risk of death due to BTC (RR = 1.35, 95% CI = 1.01-1.79) than never smokers. In the analyses by anatomic subsite, current smoking was associated with an increased risk of death from gallbladder cancer (RR = 1.89 95% CI = 1.19-3.02), whereas no evidence of an association was noted for cancers of other and unspecified biliary tract parts (RR = 1.10, 95% CI = 0.77-1.58). Moreover, mortality risk increased with an increasing number of cigarettes smoked per day and pack-years of smoking, particularly for gallbladder cancer in men. CONCLUSION: Cigarette smoking is associated with an increased risk of death from BTC, particularly gallbladder cancer, in Japanese men.

Relative risk of gastric cancer between those with and without Helicobacter pylori infection history in Japan.

Background and Aim: The causal relationship between Helicobacter pylori (H. pylori) infection and gastric cancer has been established. Although the magnitude of the carcinogenic effect of H. pylori is the next concern, it has not been sufficiently evaluated in Japan. Spontaneous disappearance of H. pylori infection may have provoked underestimation of the carcinogenic effect of the infection. To reduce the influence, a comparison should be carried out between subjects with and without the infection history. Cutoff values of H. pylori antibody lower than the manufacturer's recommendation are known to be more appropriate to diagnose history of H. pylori infection. The aim was to evaluate the carcinogenic effect of H. pylori. Methods: A case-control study consisting of 275 gastric cancer patients and 275 age- and sex-matched controls was performed. Serum H. pylori antibody was measured using the "JHM-Cap" kit with a domestic antigen (cut value of the manufacturer's recommendation was 2.3 EV: ELISA value). Using a conditional logistic model, the odds ratios (ORs) for five cutoff values adjusted for smoking and drinking doses were calculated. Results: For cutoff values of 1.25, 1.5, 1.75, 2.0, and 2.3 EV, the ORs (95% confidence intervals) were 67.7 (9.1, 502), 37.2 (8.8, 157), 21.3 (9.0, 60.2), 25.5 (9.0, 72.7), and 25.9 (9.2, 73.2), respectively. Conclusions: These results suggest that the risk ratio of gastric cancer between subjects with and without history of H. pylori infection in Japan may exceed 20.

Lifetime incidence risk for gastric cancer in the Helicobacter pylori-infected and uninfected population in Japan: A Monte Carlo simulation study.

Helicobacter pylori (H. pylori) infection is considered the leading cause of gastric cancer. Gastric cancer is currently a common cancer with high incidence and mortality rates, but it is expected that the incidence rate will gradually decrease as the H. pylori infection prevalence decreases in the future. When evaluating the effectiveness of gastric cancer prevention strategies, it is essential to note the differences in long-term cumulative risks between H. pylori-infected and uninfected populations, but this has not yet been precisely evaluated. In our study, we aimed to estimate the cumulative incidence risks of developing gastric cancer from birth to 85 years among H. pylori-infected and uninfected populations by using population-based cancer registry data and birth year-specific H. pylori infection prevalence rates. Death from gastric cancer and other causes of death were considered in the estimations of the adjusted cumulative incidence risks stratified by sex and H. pylori infection status. After performing 5000 Monte Carlo simulations with repeated random sampling using observed cancer incidence in selected three prefectures (Fukui, Nagasaki, Yamagata) of prefectural population-based cancer registry in Japan, the mean adjusted cumulative incidence risk for gastric cancer in the H. pylori-infected population was 17.0% for males and 7.7% for females and 1.0% for males and 0.5% for females in the uninfected population. These results calculated with Japanese cancer registry data may be useful in considering and evaluating future prevention strategies for gastric cancer in Japan.

Increase of serum uric acid levels associated with APOE ε2 haplotype: a clinico-genetic investigation and in vivo approach.

Elevated serum uric acid (SUA)-hyperuricemia-is caused by overproduction of urate or by its decreased renal and/or intestinal excretion. This disease, which is increasing in prevalence worldwide, is associated with both gout and metabolic diseases. Several studies have reported relationships between apolipoprotein E (APOE) haplotypes and SUA levels in humans; however, their results remain inconsistent. This prompted us to investigate the relationship between APOE polymorphisms and SUA levels. Our subjects were 5,272 Japanese men, premenopausal women, and postmenopausal women. Multiple linear regression analyses revealed the ε2 haplotype of APOE to be independently associated with higher SUA in men (N = 1,726) and postmenopausal women (N = 1,753), but not in premenopausal women (N = 1,793). In contrast, the ε4 haplotype was little related to SUA levels in each group. Moreover, to examine the effect of Apoe deficiency on SUA levels, we conducted animal experiments using Apoe knockout mice, which mimics ε2/ε2 carriers. We found that SUA levels in Apoe knockout mice were significantly higher than those in wild-type mice, which is consistent with the SUA-raising effect of the ε2 haplotype observed in our clinico-genetic analyses. Further analyses suggested that renal rather than intestinal underexcretion of urate could be involved in Apoe deficiency-related SUA increase. In conclusion, we successfully demonstrated that the ε2 haplotype, but not the ε4 haplotype, increases SUA levels. These findings will improve our understanding of genetic factors affecting SUA levels.

Effects of Helicobacter pylori eradication on gastric cancer incidence in the Japanese population: a systematic evidence review.

BACKGROUND: In Japan, there are ongoing efforts to shift the gastric cancer prevention and control policy priorities from barium-based screening to Helicobacter pylori (H. pylori)-oriented primary prevention. A comprehensive summary of the evidence regarding the effects of H. pylori eradication on the risk of gastric cancer could inform policy decisions. METHODS: We conducted a systematic review and meta-analysis of published studies evaluating the effectiveness of H. pylori eradication for the prevention of gastric cancer in otherwise healthy individuals (primary prevention) and early gastric cancer patients (tertiary prevention). RESULTS: In total, 19 studies were included. Three moderate-quality observational cohort studies showed that H. pylori eradication may be associated with a decreased risk of gastric cancer in healthy asymptomatic Japanese people. There is moderate certainty regarding the effectiveness of H. pylori eradication in patients with gastrointestinal diseases, such as peptic ulcers. A meta-analysis of 10 observational studies with otherwise healthy individuals (mainly peptic ulcer patients) yielded an overall odds ratio of 0.34 (95% CI: 0.25-0.46). Regarding tertiary prevention, the overall odds ratio for developing metachronous gastric cancer was 0.42 (95% CI: 0.35-0.51) in the eradication group in a meta-analysis of nine studies involving early gastric cancer patients who underwent endoscopic resection. CONCLUSION: H. pylori eradication is effective in preventing gastric cancer in the Japanese population, regardless of symptoms. Well-designed, large cohort studies are warranted to determine the long-term efficacy and safety of H. pylori eradication in the context of reducing the gastric cancer burden through population-based screening and treatment.

Association of self-reported moderate vegetable juice intake with small decline in kidney function in a five-year prospective study.

OBJECTIVES: Although consumption of vegetable and 100% fruit juices are an acceptable alternative for vegetable and fruit intake, information about their actual effects on kidney function is sparse. The aim of this study was to determine the association between the consumption of vegetable and fruit juices and changes in kidney function in a Japanese population over a 5-y period. METHODS: In this prospective study, we analyzed 2755 Japanese (742 men and 2013 women) individuals who participated in both the baseline and follow-up surveys in the Daiko study (a study within the Japan Multi-Institutional Collaborative Cohort study). Estimated glomerular filtration rate (eGFR) was calculated by age, sex, and serum creatinine level. For each beverage, we categorized all participants into four groups-rare (rarely consumed), low (≤2 cups/wk), moderate (3-4 cups/wk), or frequent (≥5 cups/wk) consumers of the beverage-based on a food frequency questionnaire. RESULTS: The mean baseline and follow-up eGFR (SD) were 82.4 (14.6) and 72.2 (12.6), respectively. In fully adjusted regression analyses, moderate consumption of vegetable juice was associated a lower decline in eGFR compared with the rare consumption group (ß = -1.30; P = 0.01). Moreover, stratified analyses revealed that this significant association remained in those who were young, female, non-obese, normotensive, smoked cigarettes, consumed alcohol, or exercised. However, no significant association was found in analyses for fruit juices. CONCLUSIONS: This 5-y prospective study suggested an association between self-reported moderate consumption of vegetable juice and changes (possibly smaller decline) in kidney function in a relatively healthy Japanese population.

Treatment patterns in pancreatic cancer patients based on a hospital claims database in Japan.

BACKGROUND: Pancreatic cancer treatment is evolving, but few studies have examined a nationwide trend in the treatment patterns. The purpose of this study was to clarify real-world treatment patterns for pancreatic cancer in Japan. METHODS: This retrospective study examined the treatment patterns among 68 479 patients, who had pancreatic cancer diagnosis in Medical Data Vision claims database from 2010 to 2018. We extracted relevant data on treatment options, including chemotherapy, surgery and their combination. For patients who had undergone chemotherapy, we sought to analyse the use of different chemotherapy regimens. In addition, we examined the trend in treatment patterns by age group (<59, 60-69, 70-79, ≥80). RESULTS: The trend in treatment options of pancreatic cancer remained stable from 2010 to 2018, with chemotherapy being the most common therapeutic option and surgery performed in approximately half that of chemotherapy. On the other hand, the use of chemotherapy regimen had changed during the same period. Although gemcitabine was the most commonly administrated single-agent regimen in 2010, gemcitabine + nab-paclitaxel was the most frequently used therapeutic agent in 2018. In the older age groups (age ≥80), the majority of patients was untreated (supposedly received supportive care), and the use of conventional regimens such as gemcitabine or S-1 was common among those undergoing chemotherapy. CONCLUSIONS: Although chemotherapy has been the main treatment option for pancreatic cancer, the regimens of choice have increased significantly during the last decade. With accumulating evidence on combination chemotherapy, treatment options may further evolve in the future.

Study Profile of the Japan Multi-institutional Collaborative Cohort (J-MICC) Study.

BACKGROUND: The Japan Multi-institutional Collaborative Cohort (J-MICC) study was launched in 2005 to examine gene-environment interactions in lifestyle-related diseases, including cancers, among the Japanese. This report describes the study design and baseline profile of the study participants. METHODS: The participants of the J-MICC Study were individuals aged 35 to 69 years enrolled from respondents to study announcements in specified regions, inhabitants attending health checkup examinations provided by local governments, visitors at health checkup centers, and first-visit patients at a cancer hospital in Japan. At the time of the baseline survey, from 2005 to 2014, we obtained comprehensive information regarding demographics, education, alcohol consumption, smoking, sleeping, exercise, food intake frequency, medication and supplement use, personal and family disease history, psychological stress, and female reproductive history and collected peripheral blood samples. RESULTS: The baseline survey included 92,610 adults (mean age: 55.2 [standard deviation, 9.4] years, 44.1% men) from 14 study regions in 12 prefectures. The participation rate was 33.5%, with participation ranging from 19.7% to 69.8% in different study regions. The largest number of participants was in the age groups of 65-69 years for men and 60-64 years for women. There were differences in body mass index, educational attainment, alcohol consumption, smoking, and sleep duration between men and women. CONCLUSIONS: The J-MICC Study collected lifestyle and clinical data and biospecimens from over 90,000 participants. This cohort is expected to be a valuable resource for the national and international scientific community in providing evidence to support longer healthy lives.

Association between plasma levels of homocysteine, folate, and vitamin B12, and dietary folate intake and hypertension in a cross-sectional study.

There are few studies examining the association between homocysteine (Hcy) level and the risk of hypertension with consideration for folate and vitamin B12 as related to Hcy level. We simultaneously examined the associations of plasma levels of Hcy, folate, and vitamin B12, and dietary folate intake with the prevalence of hypertension. Participants included 1046 men and 1033 women (mean age ± standard deviation: 56.0 ± 8.9 years) in the Japan Multi-Institutional Collaborative Cohort Study. Dietary folate intake was estimated using a validated food frequency questionnaire. Hypertension was defined based on measured blood pressure and use of antihypertensive medication. A total of 734 participants (35.3%) had hypertension. Multivariate-adjusted odds ratios of hypertension for the highest quartile group of Hcy were 2.36 (95% CI 1.41-3.96) in men and 1.86 (95% CI 1.11-3.11) in women, as compared with the lowest group (P for trend = 0.014 and 0.005, respectively). Dietary folate intake was not correlated with hypertension in both men and women (P for trend = 0.099 and 0.703, respectively). Plasma vitamin B12 was positively associated with hypertension only in women (P for trend = 0.027). Plasma Hcy level was positively linked with hypertension after controlling for covariates, including folate and vitamin B12.

Milk Intake and Stroke Mortality in the Japan Collaborative Cohort Study-A Bayesian Survival Analysis.

The aim of this study was to further examine the relationship between milk intake and stroke mortality among the Japanese population. We used data from the Japan Collaborative Cohort (JACC) Study (total number of participants = 110,585, age range: 40-79) to estimate the posterior acceleration factors (AF) as well as the hazard ratios (HR) comparing individuals with different milk intake frequencies against those who never consumed milk at the study baseline. These estimations were computed through a series of Bayesian survival models that employed a Markov Chain Monte Carlo simulation process. In total, 100,000 posterior samples were generated separately through four independent chains after model convergency was confirmed. Posterior probabilites that daily milk consumers had lower hazard or delayed mortality from strokes compared to non-consumers was 99.0% and 78.0% for men and women, respectively. Accordingly, the estimated posterior means of AF and HR for daily milk consumers were 0.88 (95% Credible Interval, CrI: 0.81, 0.96) and 0.80 (95% CrI: 0.69, 0.93) for men and 0.97 (95% CrI: 0.88, 1.10) and 0.95 (95% CrI: 0.80, 1.17) for women. In conclusion, data from the JACC study provided strong evidence that daily milk intake among Japanese men was associated with delayed and lower risk of mortality from stroke especially cerebral infarction.

Associations between peroxisome proliferator-activated receptor γ (PPAR-γ) polymorphisms and serum lipids: Two cross-sectional studies of community-dwelling adults.

Dyslipidemia is a well-established risk factor for cardiovascular disease. Experimental studies have reported that peroxisome proliferator-activated receptor γ (PPAR-γ) regulates adipocyte differentiation, lipid storage, and glucose metabolism. Therefore, we examined the associations between PPAR-γ polymorphisms (rs1801282, rs3856806, rs12497191, rs1151999, and rs1152003) and serum lipids in two cross-sectional studies. In the Shizuoka area of the Japan Multi-Institutional Collaborative Cohort Study, we examined 4,952 participants (3,356 men and 1,596 women) in a baseline survey and 2,245 participants (1,550 men and 695 women) in a second survey 5 years later. Outcome measures were the prevalence of dyslipidemia (low-density lipoprotein-cholesterol [LDL-C] ≥ 140 mg/dl, high-density lipoprotein-cholesterol < 40 mg/dl, triglycerides ≥ 150 mg/dl, and/or use of cholesterol-lowering drugs) and the prevalence of high LDL-C (LDL-C ≥ 140 mg/dl and/or use of cholesterol-lowering drugs). Multivariate odds ratios (ORs) were estimated by using unconditional logistic regression models. A total of 2,114 and 1,431 individuals (42.7% and 28.9%) had dyslipidemia and high LDL-C in the baseline survey, respectively, as did 933 and 716 (41.6% and 31.9%), respectively, in the second survey. In the baseline study, compared with major allele homozygotes, minor allele homozygotes of rs3856806 and rs12497191 had a 42% (OR, 0.58; 95% confidence interval (CI), 0.39-0.85) and 23% (OR, 0.77; 95% CI, 0.60-0.99) lower risk of dyslipidemia, respectively, after adjustment for potential confounding factors. In addition, minor allele homozygotes of rs3856806 had a 45% (OR, 0.55; 95% CI, 0.35-0.86) lower risk of high LDL-C. Similar risk reductions were found in the second survey. In conclusion, rs3856806 and rs12497191 polymorphisms may be related to a lower risk of dyslipidemia and high LDL-C.

Gastric cancer deaths by age group in Japan: Outlook on preventive measures for elderly adults.

In February 2013, Japan became the first country in the world to cover Helicobacter pylori eradication for chronic gastritis under its National Health Insurance (NHI) system. Now that eradication therapy is covered by NHI, its usage has increased dramatically, and gastric cancer deaths have begun to decrease. We undertook a detailed epidemiological analysis to investigate effects of expanded NHI coverage for H. pylori eradication therapy on gastric cancer deaths in specific age groups. Numbers of gastric cancer deaths were determined by referencing data from Ministry of Health, Labour and Welfare reports and "Cancer Statistics in Japan - 2018" published by the Foundation for Promotion of Cancer Research. Gastric cancer deaths across all age groups have been clearly decreasing since 2013, but deaths of people aged 80 years and older are still increasing. The number of gastric cancer deaths in people aged in their 80s was 2 times higher than in people aged in their 70s and 4 times higher than in people aged in their 60s. The number of people in their 80s who had an endoscopy was less than half that of people in their 60s and 70s. The eradication therapy has increased dramatically, and gastric cancer deaths are clearly decreasing in Japan. However, this decrease in deaths has not extended to elderly adults aged in their 80s, which suggests that measures to prevent gastric cancer in people aged 80 years and older will be critical to achieving the mission of eliminating gastric cancer in Japan.

Associations between diet and mental health using the 12-item General Health Questionnaire: cross-sectional and prospective analyses from the Japan Multi-Institutional Collaborative Cohort Study.

BACKGROUND: Mental health has become a major public health issue worldwide. Biological and epidemiological studies suggest diet has a role in the prevention or cure of mental disorders. However, further research is required to elucidate the relationship between diet and mental health. This study aimed to investigate associations between dietary intake of nutrients (macronutrients, vitamins, calcium, and fatty acids) and food groups (fish, meat and chicken, dairy products, and vegetables) and mental health among middle-aged Japanese in cross-sectional and prospective studies. METHODS: In total, 9298 men and women that participated in two areas of the Japan Multi-Institutional Collaborative Cohort Study were eligible for analysis at the baseline (cross-sectional) survey. Of these, 4701 participants were followed for about 5 years and included in the follow-up (prospective) analysis. The 12-item General Health Questionnaire (GHQ) was used to assess participants' general mental health status over the past several weeks. The average intake of 46 foods over the past year was assessed by a validated food frequency questionnaire. We also evaluated lifestyle and medical factors using a self-administered questionnaire. A cross-sectional logistic regression analysis was performed to estimate odds ratios for a GHQ score ≥ 4 (poor mental health) according to dietary intake of foods/nutrients at baseline. The prospective study used baseline dietary and lifestyle factors and GHQ scores at follow-up. RESULTS: The cross-sectional logistic regression analysis showed vegetables, protein, calcium, vitamin D, carotene and n-3 highly-polyunsaturated fatty acids were inversely associated with a GHQ score ≥ 4. On the other hand, mono-unsaturated fatty acids showed a positive association with higher GHQ score. The prospective logistic regression analysis found dairy products, calcium, vitamin B2, and saturated fatty acids were inversely correlated with a GHQ score ≥ 4. Calcium was associated with GHQ scores in both the cross-sectional and follow-up studies. In the follow-up study, the multivariable-adjusted odds ratio for a GHQ score ≥ 4 was 0.71 (95% confidence interval, 0.55-0.92) for the highest versus lowest quartiles of calorie-adjusted dietary calcium intake. CONCLUSION: Consuming particular nutrients and foods, especially calcium and dairy products, may lead to better mental health in Japanese adults.

Combined effect of weight gain within normal weight range and parental hypertension on the prevalence of hypertension; from the J-MICC Study.

The aim of this study is to show the combined effect of weight gain within normal weight range in adulthood and parental HT on the prevalence of HT. The study subjects were 44,998 individuals (19,039 men and 25,959 women) with normal weight (body mass index [BMI] 18.5-24.9) aged 35-69 years who participated in the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study. They were categorized into six groups by weight gain from age 20 years (<10 kg, and ≥10 kg) and by the number of parents having HT (no parent, one parent, and both parents). Odds ratios for HT were estimated after adjustment for age, sex, current BMI, estimated daily sodium intake, and other confounding factors. The prevalence of HT (31.5% in total subjects) gradually increased with greater weight gain from age 20 years and with greater number of parents with HT. Subjects who gained weight ≥10 kg and having both parents with HT showed the highest risk of having HT compared with those who gained weight <10 kg without parental HT (59.8% vs. 24.9%, odds ratio 4.25, 95% CI 3.53-5.13 after adjustment). This association was similarly observed in any category of age, sex, and BMI. Subjects who gained weight within normal range of BMI and having one or both parent(s) with HT showed the higher risk of having HT independent of their attained BMI in their middle ages. Thus, subjects having parent(s) with HT should avoid gaining their weight during adulthood, even within normal range of BMI, to reduce the risk of having HT.

Frequency of forest walking is not associated with prevalence of hypertension based on cross-sectional studies of a general Japanese population: a reconfirmation by the J-MICC Daiko Study.

Forest walking or Shinrin-yoku is a health promotion activity in Japan. Although some studies have reported the acute effects of walking a few hours in forested areas in reducing blood pressure level compared to other environments, studies investigating whether successive walking has long-term effects in lowering blood pressure levels or lowering prevalence of hypertension are rare. This study aimed to reconfirm the presence or absence of an association between the frequency of forest walking and prevalence of hypertension in a Japanese population. This J-MICC Daiko Study was conducted targeting residents in Nagoya City. A total of 5,109 participants (1,452 men and 3,657 women; age, mean ± standard deviation: 52.5 ± 10.3 years) were included in the analysis. Age-adjusted blood pressure level by frequency of forest walking was not significant. After adjusting for age and lifestyle, the adjusted odds ratios (aORs) of the most frequent group (n=88, 1.7%; once a week or more group) relative to the less than once a month group (n=4,558, 89.2%) for prevalence of hypertension were not also significant [0.80 (95% CI: 0.40-1.62) for men and 1.48 (95% CI: 0.73-3.00) for women]. This study reconfirmed that either lowering blood pressure level or lowering the prevalence of hypertension is not associated with frequency of forest walking, similar to the results of our previous J-MICC Shizuoka Study. Given that these two studies were cross-sectional studies, cohort studies investigating the causal relationship are required to evaluate the effect of frequent forest walking on the prevention of hypertension.