BMI and Cardiometabolic Traits in Japanese: A Mendelian Randomization Study.

BACKGROUND: Although many observational studies have demonstrated significant relationships between obesity and cardiometabolic traits, the causality of these relationships in East Asians remains to be elucidated. METHODS: We conducted individual-level Mendelian randomization (MR) analyses targeting 14,083 participants in the Japan Multi-Institutional Collaborative Cohort Study and two-sample MR analyses using summary statistics based on genome-wide association study data from 173,430 Japanese. Using 83 body mass index (BMI)-related loci, genetic risk scores (GRS) for BMI were calculated, and the effects of BMI on cardiometabolic traits were examined for individual-level MR analyses using the two-stage least squares estimator method. The ß-coefficients and standard errors for the per-allele association of each single-nucleotide polymorphism as well as all outcomes, or odds ratios with 95% confidence intervals were calculated in the two-sample MR analyses. RESULTS: In individual-level MR analyses, the GRS of BMI was not significantly associated with any cardiometabolic traits. In two-sample MR analyses, higher BMI was associated with increased risks of higher blood pressure, triglycerides, and uric acid, as well as lower high-density-lipoprotein cholesterol and eGFR. The associations of BMI with type 2 diabetes in two-sample MR analyses were inconsistent using different methods, including the directions. CONCLUSION: The results of this study suggest that, even among the Japanese, an East Asian population with low levels of obesity, higher BMI could be causally associated with the development of a variety of cardiometabolic traits. Causality in those associations should be clarified in future studies with larger populations, especially those of BMI with type 2 diabetes.

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

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

GWAS of folate metabolism with gene-environment interaction analysis revealed the possible role of lifestyles in the control of blood folate metabolites in Japanese - the J-MICC Study.

BACKGROUND: The present genome-wide association study (GWAS) aimed to reveal the genetic loci associated with folate metabolites as well as to detect related gene-environment interactions in Japanese. METHODS: We conducted the GWAS of plasma homocysteine (Hcy), folic acid (FA), and vitamin B12 (VB12) levels in the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study participants who joined from 2005 to 2012, and also estimated gene-environment interactions. In the replication phase, we used data from the Yakumo Study conducted in 2009. In the discovery phase, data of 2,263 participants from four independent study sites of the J-MICC Study were analyzed. In the replication phase, data of 573 participants from the Yakumo Study were analyzed. RESULTS: For Hcy, MTHFR locus on chr 1, NOX4 on chr 11, CHMP1A on chr 16, and DPEP1 on chr 16 reached genome-wide significance (P < 5×10-8). MTHFR also associated with FA, and FUT2 on chr 19 associated with VB12. We investigated gene-environment interactions in both studies and found significant interactions between MTHFR C677T and ever drinking, current drinking, and physical activity > 33% on Hcy (ß = 0.039, 0.038 and -0.054, P = 0.018, 0.021 and < 0.001, respectively) and the interaction of MTHFR C677T with ever drinking on FA (ß = 0.033, P = 0.048). CONCLUSIONS: The present GWAS revealed the folate metabolism-associated genetic loci and gene-environment interactions with drinking and physical activity in Japanese, suggesting the possibility of future personalized CVD prevention.

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

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

A nationwide survey of Schaaf-Yang syndrome in Japan.

Schaaf-Yang syndrome (SYS) is a congenital disorder characterized by developmental delay, autism spectrum disorder and congenital joint contractures. In this study, a nationwide epidemiological questionnaire-based survey of SYS in the Japanese population was conducted to establish patient numbers, clinical features and genetic information. In the primary survey, we investigated the number of SYS patients. In the secondary survey, we obtained and analyzed detailed clinical and genetic information of SYS patients. This survey collected information on 25 genetically-confirmed patients. The major clinical symptoms included neonatal hypotonia (96% of the patients), poor suck in infancy (82%), developmental delay (100%) and joint contractures (83%). Other main symptoms and findings included characteristic facial features (100%), small hands (92%), eye abnormalities (92%) and short stature (79%). Based on the information collected on activities of daily living, 71% of patients were unable to walk, while 67%, 71%, and 81% of patients required full assistance with eating, toileting and bathing, respectively. Regarding inheritability, the genetic analysis of 21 patients revealed that 14 (67%) carried de novo truncating variants in the melanoma antigen L2 (MAGEL2) gene and seven (33%) had inherited truncating variants from their fathers who were carriers. This survey revealed the clinical and genetic features in Japanese SYS patients. The majority of SYS patients required assistance in many aspects of daily living, and there were a certain number of carriers of the imprinting disorder.

The Impact of Marital Transitions on Vegetable Intake in Middle-aged and Older Japanese Adults: A 5-year Longitudinal Study.

BACKGROUND: Marital transitions are associated with adverse health events, such as mortality and cardiovascular disease. Since marital transitions (eg, becoming widowed) are unavoidable life events, it is necessary to identify modifiable intermediate outcomes. Thus, we examined the association between marital transitions and vegetable intake among middle-aged and older Japanese adults. METHODS: This longitudinal study included Japanese adults aged 40-79 years who received an annual health checkup between 2007 and 2011 (baseline) and 5 years later (follow-up). Marital transitions were classified as whether and what type of transition occurred during the 5-year period and comprised five groups: consistently married, married to widowed, married to divorced, not married to married, and remained not married. Changes in total vegetable, green and yellow vegetable, and light-colored vegetable intake from baseline to follow-up were calculated using the Food Frequency Questionnaire. RESULTS: Data from 4,813 participants were analyzed (mean age, 59.4 years; 44.1% women). Regarding marital transitions, 3,960 participants were classified as "consistently married," 135 as "married to widowed," 40 as "married to divorced," 60 as "not married to married," and 529 as "remained not married." Multivariable linear regression analysis revealed that compared to consistently married, married to widowed was inversely associated with the change in total vegetable intake (ß = -16.64, SE = 7.68, P = 0.030) and light-colored vegetable intake (ß = -11.46, SE = 4.33, P = 0.008). CONCLUSION: Our findings suggest that being widowed could result in a reduced intake of vegetables. Hence, dietary counseling according to marital situation is necessary.

Assessing the Relationship Between High-sensitivity C-reactive Protein and Kidney Function Employing Mendelian Randomization in the Japanese Community-based J-MICC Study.

BACKGROUND: Inflammation is thought to be a risk factor for kidney disease. However, whether inflammatory status is either a cause or an outcome of chronic kidney disease remains controversial. We aimed to investigate the causal relationship between high-sensitivity C-reactive protein (hs-CRP) and estimated glomerular filtration rate (eGFR) using Mendelian randomization (MR) approaches. METHODS: A total of 10,521 participants of the Japan Multi-institutional Collaborative Cohort Study was analyzed in this study. We used two-sample MR approaches (the inverse-variance weighted (IVW), the weighted median (WM), and the MR-Egger method) to estimate the effect of genetically determined hs-CRP on kidney function. We selected four and three hs-CRP associated single nucleotide polymorphisms (SNPs) as two instrumental variables (IV): IVCRP and IVAsian, based on SNPs previously identified in European and Asian populations. IVCRP and IVAsian explained 3.4% and 3.9% of the variation in hs-CRP, respectively. RESULTS: Using the IVCRP, genetically determined hs-CRP was not significantly associated with eGFR in the IVW and the WM methods (estimate per 1 unit increase in ln(hs-CRP), 0.000; 95% confidence interval [CI], -0.019 to 0.020 and -0.003; 95% CI, -0.019 to 0.014, respectively). For IVAsian, we found similar results using the IVW and the WM methods (estimate, 0.005; 95% CI, -0.020 to 0.010 and -0.004; 95% CI, -0.020 to 0.012, respectively). The MR-Egger method also showed no causal relationships between hs-CRP and eGFR (IVCRP: -0.008; 95% CI, -0.058 to 0.042; IVAsian: 0.001; 95% CI, -0.036 to 0.036). CONCLUSION: Our two-sample MR analyses with different IVs did not support a causal effect of hs-CRP on eGFR.

Application of the RNA interference technique to Xenopus embryos: Specific reduction of the ß-catenin gene products by short double-stranded RNA produced by recombinant human Dicer.

RNA interference (RNAi) is a technique for suppressing the function of specific genes and is widely used in many organisms, including yeast, nematodes, flies, plants, mice, and cultured mammalian cells. As of date, this technique has not been successfully applied to Xenopus laevis embryos. In this study, we applied RNAi to Xenopus embryos using ß-catenin as a model gene. Injection of long double-stranded RNA (dsRNA) corresponding to the 3'-untranslated region of ß-catenin mRNA into embryos induced embryonic lethality without any specific phenotype. However, injection of short dsRNA, generated from long dsRNA by treatment with recombinant human Dicer, into embryos resulted in decreased expression of endogenous ß-catenin mRNA and protein, as well as decreased Wnt signaling activity in the embryos. The decrease in ß-catenin mRNA and protein levels was observed only after mid-blastula transition. Embryos injected with short dsRNA showed a characteristic phenotype of enlarged anterior structures and loss of posterior structures. These phenotypes, as well as the increased expression of the anterior gene and decreased expression of the posterior gene, suggest that RNAi against the ß-catenin gene suppresses the "late Wnt signaling" involved in proper anterior-posterior patterning of Xenopus embryos. The effect of RNAi on Xenopus embryos was also found to be sensitive to temperature. These results strongly suggest that the RNAi technique can be applied to Xenopus embryos using short dsRNAs, appropriate temperature control, and proper selection of target genes.

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.

High phospho-histone H3 expression uniquely predicts favorable survival among four markers of cellular proliferation in colorectal cancer.

Colorectal cancer (CRC) is one of the most frequent gastrointestinal cancers worldwide, with high morbidity and mortality rates. Despite numerous attempts to identify prognostic markers for the CRC patients, the significance of the association of cellular proliferation markers with survival is controversial. Here we used immunohistochemistry to detect four markers of cellular proliferation expressed in primary CRC tissue specimens (n = 269) to assess their potential to serve as prognostic factors. CRC cells variably expressed phospho-histone H3 (PHH3) (range, 0-76 per high-powered field (HPF); median, 7 per HPF), cyclin A (CCNA) (range, 11.3-73.7%; median, 32%), geminin (GMNN) (range, 7.8-82.0%; median, 37.1%), and marker of proliferation Ki-67 (MKI67) (range, 4.9-96.6%; median, 49.6%). Among them, patients with PHH3-high (≥7 per HPF) tumors uniquely experienced significantly longer 5-year survival than those with PHH3-low (≤6 per HPF) (81.8% vs. 65.5%; P = 0.0047). Multivariable Cox hazards regression analysis identified PHH3-high (hazard ratio, 0.54; 95% confidence interval, 0.31-0.92; P = 0.025) as potential favorable factors. PHH3 levels inversely associated with pT stage (P < 0.0001) and were significantly and inversely associated with tumor diameter (ρ = -0.314, P < 0.0001). These findings support the use of PHH3 immunohistochemistry for predicting the prognoses of patients with CRC.