Association between consumption of small fish and all-cause mortality among Japanese: the Japan Multi-Institutional Collaborative Cohort Study

OBJECTIVE

Although small fish are an important source of micronutrients, the relationship between their intake and mortality remains unclear. This study aimed to clarify the association between intake of small fish and all-cause and cause-specific mortality.

DESIGN

We used the data from a cohort study in Japan. The frequency of the intake of small fish was assessed using a validated FFQ. The hazard ratio (HR) and 95 % confidence interval (CI) for all-cause and cause-specific mortality according to the frequency of the intake of small fish by sex were estimated using a Cox proportional hazard model with adjustments for covariates.

SETTING

The Japan Multi-Institutional Collaborative Cohort Study.

PARTICIPANTS

A total of 80 802 participants (34 555 males and 46 247 females), aged 35-69 years.

RESULTS

During a mean follow-up of 9·0 years, we identified 2482 deaths including 1495 cancer-related deaths. The intake of small fish was statistically significantly and inversely associated with the risk of all-cause and cancer mortality in females. The multivariable-adjusted HR (95 % CI) in females for all-cause mortality according to the intake were 0·68 (0·55, 0·85) for intakes 1-3 times/month, 0·72 (0·57, 0·90) for 1-2 times/week and 0·69 (0·54, 0·88) for ≥ 3 times/week, compared with the rare intake. The corresponding HR (95 % CI) in females for cancer mortality were 0·72 (0·54, 0·96), 0·71 (0·53, 0·96) and 0·64 (0·46, 0·89), respectively. No statistically significant association was observed in males.

CONCLUSIONS

Intake of small fish may reduce the risk of all-cause and cancer mortality in Japanese females.

Association between brown sugar intake and decreased risk of cancer in the Amami islands region, Japan

BACKGROUND AND OBJECTIVES

Although excess white sugar intake imposes various health burdens, brown sugar is high in minerals, polyphenols, and polycosanol. However, few epidemiological studies have assessed brown sugar intake for health benefit. People in the Amami islands region, with a relatively high proportion of individuals with longevity, consume brown sugar as a type of refreshment. This cohort study was conducted in Amami to clarify the association of brown sugar intake with mortality risk and cancer incidence.

METHODS AND STUDY DESIGN

Participants were recruited from the general population of Amami as part of the Japan Multi-Institutional Collaborative Cohort Study. The number of eligible participants was 5004 (2057 men and 2947 women). During the median follow-up period of 13.4 years, 274 deaths and 338 cases of cancer were observed. HRs and 95% CIs were estimated using the Cox proportional hazard model, after adjusting for sugar-related and other variables.

RESULTS

After adjusting for their related confounding factors, brown sugar intake was associated with decreased HRs and a decreasing trend for all-site and stomach cancer incidence (p = 0.001 and 0.017, respectively) in women and men, and for breast cancer incidence (p = 0.034) in women. Additionally, a decreasing trend in the HRs for lung cancer incidence was observed among never and ex-smokers (p = 0.039). Decreased HRs for overall death, cancer, and cardiovascular disease were not apparent.

CONCLUSIONS

Brown sugar intake was associated with decreased risk of all-site, stomach, and breast cancer incidences in the Amami population.

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.

Association Between Nursing Discussions, Resilience, Workplace Social Support and Burnout: A Quantitative Study in Japan

Background

Although it is known that resilience is negatively associated with burnout, and that certain interventions can effectively increase resilience, little is known about online resilience-enhancing interventions during the COVID-19 crisis. The aim of this study was to identify the association between an online resilience-enhancing intervention and workplace social support, and burnout among nurses working in the mainland and remote islands of Japan during the COVID-19 crisis.

Methods

Pretest-posttest was conducted between April 2020 and February 2021, and the questionnaire survey included the bidimensional resilience scale, the Japanese version of Pine's Burnout Measure, and the workplace social support scale. Changes in burnout, resilience, and social support and the associations with nursing discussions as intervention were analyzed. Participants were 98 Nurses with 1 to 10 years of experience from Japan's mainland and remote island hospitals of Kagoshima Prefecture participated in a baseline survey in April 2020. Of these, 76 participated in a secondary survey in September 2020, and 69 participated in the intervention program and a third survey in February 2021. The online intervention over Zoom consisted of small-group nursing discussions based on the broaden-and-build theory.

Results

Changes in burnout showed a significant negative association with change in workplace social support (Coef. = -0.019, 95% CI -0.035- -0.003), as did the interaction between change in acquired resilience and intervention (Coef. = -0.088, 95% CI -0.164- -0.011).

Conclusion

Change in workplace social support was significantly negatively associated with changes in burnout, as was the interaction of intervention and acquired resilience. Promotion of this intervention and making workplace social support more accessible may contribute to reduce burnout in nurses.

Associations of Genome-Wide Polygenic Risk Score and Risk Factors With Hypertension in a Japanese Population

Background:

Although many polygenic risk scores (PRS) for cardiovascular traits have been developed in European populations, it is an urgent task to construct a PRS and to evaluate its ability in non-European populations. We developed a genome-wide PRS for blood pressure in a Japanese population and examined the associations between this PRS and hypertension prevalence.

Methods:

We performed a cross-sectional study in 11 252 Japanese individuals who participated in the J-MICC (Japan Multi-Institutional Collaborative Cohort) study. Using publicly available GWAS summary statistics from Biobank Japan, we developed the PRS in the target data (n=7876). With >30 000 single nucleotide polymorphisms, we evaluated PRS performance in the test data (n=3376). Hypertension was defined as systolic blood pressure of 130 mm Hg or more, or diastolic blood pressure of 85 mm Hg or more, or taking an antihypertensive drug.

Results:

Compared with the middle PRS quintile, the prevalence of hypertension at the top PRS quintile was higher independently from traditional risk factors (odds ratio, 1.73 [95% CI, 1.32–2.27]). The difference of mean systolic blood pressure and diastolic blood pressure between the middle and the top PRS quintile was 4.55 (95% CI, 2.26–6.85) and 2.32 (95% CI, 0.86–3.78) mm Hg, respectively. Subgroups reflecting combinations of Japanese PRS and modifiable lifestyles and factors (smoking, alcohol intake, sedentary time, and obesity) were associated with the prevalence of hypertension. A European-derived PRS was not associated with hypertension in our participants.

Conclusions:

A PRS for blood pressure was significantly associated with hypertension and BP traits in a general Japanese population. Our findings also highlighted the importance of a combination of PRS and risk factors for identifying high-risk subgroups.

Associations of breastfeeding history with metabolic syndrome and cardiovascular risk factors in community-dwelling parous women: The Japan Multi-Institutional Collaborative Cohort Study

OBJECTIVE

The aim of the present study was to investigate the associations between breastfeeding and the prevalence of metabolic syndrome in community-dwelling parous women and to clarify whether the associations depend on age.

METHODS

The present cross-sectional study included 11,118 women, aged 35-69 years. Participants' longest breastfeeding duration for one child and their number of breastfed children were assessed using a self-administered questionnaire, and their total breastfeeding duration was approximated as a product of the number of breastfed children and the longest breastfeeding duration. The longest and the total breastfeeding durations were categorized into none and tertiles above 0 months. Metabolic syndrome and cardiovascular risk factors (obesity, hypertension, dyslipidemia, and hyperglycemia) were defined as primary and secondary outcomes, respectively. Associations between breastfeeding history and metabolic syndrome or each cardiovascular risk factor were assessed using multivariable unconditional logistic regression analysis.

RESULTS

Among a total of 11,118 women, 10,432 (93.8%) had ever breastfed, and 1,236 (11.1%) had metabolic syndrome. In participants aged <55 years, an inverse dose-response relationship was found between the number of breastfed children and the prevalence of metabolic syndrome; multivariable-adjusted odds ratios for 1, 2, 3, and ≥4 breastfed children were 0.60 (95% confidence interval [CI]: 0.31 to 1.17), 0.50 (95% CI: 0.29 to 0.87), 0.44 (95% CI: 0.24 to 0.84), and 0.35 (95% CI: 0.14 to 0.89), respectively. The longest and total breastfeeding durations of longer than 0 months were also associated with lower odds of metabolic syndrome relative to no breastfeeding history in participants aged <55 years. In contrast, all measures of breastfeeding history were not significantly associated with metabolic syndrome and cardiovascular risk factors in participants aged ≥55 years old.

CONCLUSIONS

Breastfeeding history may be related to lower prevalence of metabolic syndrome in middle-aged parous women.

695Gene and environmental factors for liver fibrosis among Japanese general population with NAFLD

Background

A part of nonalcoholic fatty liver disease (NAFLD) develops nonalcoholic steatohepatitis (NASH), liver cirrhosis and hepatocellular carcinoma. Metabolic syndrome is involved in their development, and hepatic fibrosis plays an important role in their pathogenesis. Patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene encode proteins on hepatic lipid metabolism regulation, and PNPLA3 gene polymorphism is associated with the development and progression of NAFLD. To investigate the gene and environmental factors, and their interaction for liver fibrosis, we conducted a prospective study among Japanese general population with NAFLD.

Methods

The subjects were 295 general residents who participated as a part of the Japan Multi-Institutional Collaborative Cohort (J-MICC) study in Kagoshima, Japan, and were followed for 5 years. NAFLD was defined as fatty liver using abdominal ultrasonography. PNPLA3 C/G polymorphism (rs738409) was analysed using TaqMan PCR. Hepatic fibrosis was defined using FIB 4 index (≥1.3). Logistic regression model was used to estimate the odds ratios (ORs) after adjusted for confounding factors.

Results

Mean age was 55.1 years and liver fibrosis was observed at 73.2% among NAFLD subjects. No environmental factors were associated with liver fibrosis, and PNPLA3 GG genotype was not associated with liver fibrosis, too. However, the ORs of CC & CG, and GG genotypes for dyslipidemia was respectively 0.45 (0.19-1.04) and 11.9 (1.81-78.4), and their interaction was significant (p = 0.01).

Conclusions

The interaction between PNPLA3 GG gene polymorphism and dyslipidemia for liver fibrosis was observed.

Key messages

Genetic susceptibility with dyslipidemia may be involved in liver fibrosis of NAFLD.

Population-Based Impact of Smoking, Drinking, and Genetic Factors on HDL-Cholesterol Levels in J-MICC Study Participants

BACKGROUND

Environmental and genetic factors are suggested to exhibit factor-based association with HDL-cholesterol (HDL-C) levels. However, the population-based effects of environmental and genetic factors have not been compared clearly. We conducted a cross-sectional study using data from the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study to evaluate the population-based impact of smoking, drinking, and genetic factors on low HDL-C.

METHODS

Data from 11,498 men and women aged 35-69 years were collected for a genome-wide association study (GWAS). Sixty-five HDL-C-related SNPs with genome-wide significance (P < 5 × 10^-8) were selected from the GWAS catalog, and seven representative SNPs were defined, and the population-based impact was estimated using population attributable fraction (PAF).

RESULTS

We found that smoking, drinking, daily activity, habitual exercise, egg intake, BMI, age, sex and the SNPs CETP rs3764261, APOA5 rs662799, LIPC rs1800588, LPL rs328, ABCA1 rs2575876, LIPG rs3786247, and APOE rs429358 were associated with HDL-C levels. The gene-environmental interactions on smoking and drinking were not statistically significant. The PAF for low HDL-C was the highest in men (63.2%) and in rs3764261 (31.5%) of the genetic factors, and the PAFs of smoking and drinking were 23.1% and 41.8%, respectively.

CONCLUSIONS

The present study showed that the population-based impact of genomic factor CETP rs3764261 for low HDL-C was higher than that of smoking and lower than that of drinking.

Effect of Underlying Cardiometabolic Diseases on the Association Between Sedentary Time and All-Cause Mortality in a Large Japanese Population: A Cohort Analysis Based on the J-MICC Study

Background This study aimed to determine the association between sedentary time and mortality with regard to leisure-time physical activity with or without cardiometabolic diseases such as hypertension, dyslipidemia, and diabetes mellitus. Methods and Results Using data from the J-MICC (Japan Multi-Institutional Collaborative Cohort) Study, 64 456 participants (29 022 men, 35 434 women) were analyzed. Hazard ratios (HRs) and 95% CIs were used to characterize the relative risk of all-cause mortality to evaluate its association with sedentary time (categorical variables: <5, 5 to <7, 7 to <9, ≥9 h/d and 2-hour increments in exposure) according to the self-reported hypertension, dyslipidemia, and diabetes mellitus using a Cox proportional hazards model. A total of 2257 participants died during 7.7 years of follow-up. The corresponding HRs for each 2-hour increment in sedentary time among participants with all factors, no factors, hypertension, dyslipidemia, and diabetes mellitus were 1.153 (95% CI, 1.114-1.194), 1.125 (95% CI, 1.074-1.179), 1.202 (95% CI, 1.129-1.279), 1.176 (95% CI, 1.087-1.273), and 1.272 (95% CI, 1.159-1.396), respectively. Furthermore, when analyzed according to the combined different factors (hypertension, dyslipidemia, and diabetes mellitus), HRs increased with each additional factor, and participants reporting all 3 conditions had the highest HR of 1.417 (95% CI, 1.162-1.728) independently of leisure-time metabolic equivalents. Conclusions The association between sedentary time and increased mortality is stronger among patients with hypertension, dyslipidemia, and diabetes mellitus regardless of leisure-time physical activity in a large Japanese population.

Impact of PSCA Polymorphisms on the Risk of Duodenal Ulcer

BACKGROUND

While duodenal ulcer (DU) and gastric cancer (GC) are both H. pylori infection-related diseases, individuals with DU are known to have lower risk for GC. Many epidemiological studies have identified the PSCA rs2294008 T-allele as a risk factor of GC, while others have found an association between the rs2294008 C-allele and risk of DU and gastric ulcer (GU). Following these initial reports, however, few studies have since validated these associations. Here, we aimed to validate the association between variations in PSCA and the risk of DU/GU and evaluate its interaction with environmental factors in a Japanese population.

METHODS

Six PSCA SNPs were genotyped in 584 DU cases, 925 GU cases, and 8,105 controls from the Japan Multi-Institutional Collaborative Cohort (J-MICC). Unconditional logistic regression models were applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between the SNPs and risk of DU/GU.

RESULTS

PSCA rs2294008 C-allele was associated with per allele OR of 1.34 (95% CI, 1.18-1.51; P = 2.28 × 10-6) for the risk of DU. This association was independent of age, sex, study site, smoking habit, drinking habit, and H. pylori status. On the other hand, we did not observe an association between the risk of GU and PSCA SNPs.

CONCLUSIONS

Our study confirms an association between the PSCA rs2294008 C-allele and the risk of DU in a Japanese population.

Association between alcohol intake pattern and metabolic syndrome components and simulated change by alcohol intake reduction: A cross-sectional study from the Japan Multi-Institutional Collaborative Cohort Study

To investigate the association between alcohol intake pattern in amount and frequency and metabolic syndrome (Mets) components, we simulated the change in the prevalence of Mets components by intake reduction. In order to manage Mets, alcohol intake reduction with moderation of intake pattern is required. However, evidence investigating the comparative impact of alcohol intake reduction in amount and frequency for Mets components is limited. We conducted a large-scale cross-sectional study in the general Japanese population. The study subjects included 37,371 non-drinkers and current drinkers recruited in the Japan Multi-Institutional Collaborative Cohort Study. Odds ratios (ORs) for Mets components according to alcohol intake amount and frequency were estimated using a multiple logistic regression model. The prevalence of Mets components was estimated after assumed alcohol intake reduction of a) none, b) 10 g/day (men) or 5 g/day (women), c) 20 g/day (men) or 10 g/day (women), d) less than 20 g/day (men) or 10 g/day (women) for moderate-to-heavy drinkers, e) 1-2 times/week, and f) 3-4 times/week. The ORs with alcohol intake amount and frequency increased with high blood pressure while decreasing with dyslipidemia. A J-shaped association was observed between intake amount and Mets. The estimated prevalence (%) of high blood pressure and dyslipidemia in men were a) 45.2, b) 43.0, c) 41.4, d) 40.4, e) 42.9, and f) 42.0; and a) 50.3, b) 51.8, c) 52.9, d) 50.2, e) 52.7, and f) 53.4 in women. The estimated prevalence of high blood pressure in women did not evidently decrease. Simulated alcohol intake reduction showed decreased prevalence for high blood pressure and increased prevalence for dyslipidemia in men after reduced intake amount and frequency. The largest decreased prevalence for high blood pressure was observed in men when all moderate-to-heavy drinkers reduced their alcohol intake amount to less than 20 g/day.

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 [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.

Advancement of hepatic fibrosis among general women with/without NAFLD

Background

Nonalcoholic fatty liver disease (NAFLD) is increasing, being prevalent at 30% of the general population worldwide. A part of NAFLD develops nonalcoholic steatohepatitis (NASH), liver cirrhosis and hepatocellular carcinoma. Hepatic fibrosis plays an important role in their pathogenesis. However, it is unclear how hepatic fibrosis is observed and advanced in NAFLD among general population. To investigate the hepatic fibrosis among general population, we prospectively observed hepatic fibrosis using serum markers.

Methods

The subjects were 228 women who participated as a part of the Japan Multi-Institutional Collaborative Cohort (J-MICC) study in Kagoshima, Japan, and were followed from 2005 to 2014. NAFLD was defined as fatty liver by abdominal ultrasonography; consuming ethanol &lt; 20 g/day; and being none hepatitis B and C carriers. NAFLD were confirmed after two-time consecutive examination, because its disappearance is ambiguous in some cases. Hepatic fibrosis was evaluated using serum M2BPGi and Type IV collagen 7s. The comparison of their changed values between groups was done using the ANOVA adjusted for age. The association between their change and related factors was done using general linear regression model.

Results

The prevalence of NAFLD was 31.6% at baseline. In the 5-year observation, the NAFLD + =&gt; NAFLD + ( ++) group was 23.7%; − +, 2.6%; + −, 7.9%; and - - (control), 65.8%. The values of M2BPGi and Type IV collagen 7s were higher in ++, -+, +- groups than controls at baseline. The change of M2BPGi values was observed in all groups, including controls, and the changed values were higher in ++ and -+ groups. Higher creatinine levels were positively associated with change of M2BPGi values. In contrast, the change of Type IV collagen 7s was not apparent.

Conclusions

This study suggested hepatic fibrosis was advanced with age among general women without NAFLD, and the presence of NAFLD enhanced hepatic fibrosis more.

Key messages

Hepatic fibrosis may be slightly developing with age among general population, and will be enhanced with fatty liver. It is important to prevent fatty liver development to control risk factors, such as obesity and metabolic syndrome, to reduce the risk of NASH, liver cirrhosis and hepatocellular carcinoma.

Comprehensive unhealthy lifestyle is associated with alcohol consumption as J-shaped curve

Background

Alcohol consumption is a confirmed risk factor for cancer as well as cardiovascular and other diseases. Decreased and increased risks with light and heavy consumption, respectively (J-shaped associations), were reported for total mortality. However, whether alcohol itself or its related-factors are involved in this association, is unclear. This study examined the background characteristics of comprehensive lifestyles and clinical factors according to alcohol consumption, using data from a baseline survey of large-scaled cohort study conducted among the general Japanese using Breslow’s healthy lifestyle index.

Methods

The study subjects were 23,885 males and 28,165 females aged 35 to 69 years, who were enrolled in the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study. To determine unhealthy lifestyle scores, smoking, exercise, sleeping duration, breakfast consumption, eating between meals, and obesity were combined. The odds ratios (ORs) of unhealthy lifestyles and clinical factors according to alcohol consumption were estimated using a logistic regression model.

Results

The ORs of combined unhealthy lifestyles decreased among light drinkers in males (0.73, 0.67-0.80) and females (0.88, 0.82-0.95), and increased among heavy drinkers (1.52, 1.27-1.83; 2.15, 1.44-3.20, respectively). These associations were not found for each unhealthy lifestyle and atherosclerosis-related factors, except for less breakfast intake in males and less frequent habitual exercise in females.

Conclusions

The present study suggests that the J-shaped association between comprehensive unhealthy lifestyle and alcohol consumption may be an important background factor of the association between alcohol consumption and risk of total mortality. Further study for total mortality with them is warranted.

Key messages

This study showed comprehensive unhealthy lifestyles were observed not only among heavy drinkers, but also among non-drinkers. Light drinkers have more healthy lifestyles, which contribute to their better health.

Genome-wide association study revealed novel loci which aggravate asymptomatic hyperuricaemia into gout

Objective

The first ever genome-wide association study (GWAS) of clinically defined gout cases and asymptomatic hyperuricaemia (AHUA) controls was performed to identify novel gout loci that aggravate AHUA into gout.

Methods

We carried out a GWAS of 945 clinically defined gout cases and 1003 AHUA controls followed by 2 replication studies. In total, 2860 gout cases and 3149 AHUA controls (all Japanese men) were analysed. We also compared the ORs for each locus in the present GWAS (gout vs AHUA) with those in the previous GWAS (gout vs normouricaemia).

Results

This new approach enabled us to identify two novel gout loci (rs7927466 of CNTN5 and rs9952962 of MIR302F) and one suggestive locus (rs12980365 of ZNF724) at the genome-wide significance level (p<5.0×10^–8). The present study also identified the loci of ABCG2, ALDH2 and SLC2A9. One of them, rs671 of ALDH2, was identified as a gout locus by GWAS for the first time. Comparing ORs for each locus in the present versus the previous GWAS revealed three ‘gout vs AHUA GWAS’-specific loci (CNTN5, MIR302F and ZNF724) to be clearly associated with mechanisms of gout development which distinctly differ from the known gout risk loci that basically elevate serum uric acid level.

Conclusions

This meta-analysis is the first to reveal the loci associated with crystal-induced inflammation, the last step in gout development that aggravates AHUA into gout. Our findings should help to elucidate the molecular mechanisms of gout development and assist the prevention of gout attacks in high-risk AHUA individuals.

Association of exposure level to passive smoking with hypertension among lifetime nonsmokers in Japan: a cross-sectional study

Brief exposure to passive smoking immediately elevates blood pressure. However, little is known about the association between exposure to passive smoking and chronic hypertension. We aimed to examine this association in a cross-sectional study, after controlling multiple potential confounders.Participants included 32,098 lifetime nonsmokers (7,216 men and 24,882 women) enrolled in the Japan Multi-Institutional Collaborative Cohort Study. Passive smoking was assessed using a self-administered questionnaire. The single question about exposure to passive smoking had five response options: "sometimes or almost never," "almost every day, 2 hours/day or less," "almost every day, 2 to 4 hours/day," "almost every day, 4 to 6 hours/day," and "almost every day, 6 hours/day or longer." Hypertension was defined as any of the following: systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, or use of antihypertensive medication. Multivariate-adjusted odds ratio (OR) and 95% confidence interval (CI) for hypertension were estimated by exposure level to passive smoking using unconditional logistic regression models.The multivariate-adjusted OR for hypertension in those exposed almost every day was 1.11 (95% CI: 1.03-1.20) compared with those exposed sometimes or almost never. The OR for a 1-hour per day increase in exposure was 1.03 (95% CI: 1.01-1.06, Pfor trend = .006). This association was stronger in men than in women; the ORs were 1.08 (95% CI: 1.01-1.15, Pfor trend = .036) and 1.03 (95% CI: 1.00-1.05, Pfor trend = .055), respectively.Our findings suggest importance of tobacco smoke control for preventing hypertension.

Association of genetic risk score and chronic kidney disease in a Japanese population

Chronic kidney disease (CKD) is a public health problem worldwide including Japan. Recent genome-wide association studies have discovered CKD susceptibility variants. We developed a genetic risk score (GRS) based on CKD-associated variants and assessed a possibility that the GRS can improve the discrimination capability for the prevalence of CKD in a Japanese population. The present study consists of 11 283 participants randomly selected from 12 Japan Multi-Institutional Collaborative Cohort Study sites. Individual GRS was constructed combining 18 single-nucleotide polymorphisms identified in a Japanese population. Participants with eGFR <60 mL/min per 1.73 m² was defined as case (stage 3 CKD or higher) in this study. Logistic regression analysis was used to examine the association between the GRS and CKD risk with adjustment for sex, age, hypertension and type 2 diabetes mellitus. The frequency of individuals with CKD was 8.3%, which was relatively low compared with those previously reported in a Japanese population. The odds ratio of having CKD was 1.120 (95% confidence interval: 1.042-1.203) per 10 GRS increment in the fully adjusted model (P = 0.002). The C-statistic was significantly increased in the model with the GRS, comparing with the model without the GRS (0.720 vs 0.719, P_difference  = 0.008). Increment of the GRS was associated with increased risk of CKD. Additionally, the GRS significantly improved the discriminatory ability of CKD prevalence in a Japanese population; however, the improvement of discriminatory ability brought about by the GRS seemed to be small compared with that of non-genetic CKD risk factors.

Genome-Wide Association Study of Renal Function Traits: Results from the Japan Multi-Institutional Collaborative Cohort Study

BACKGROUND

Chronic kidney disease (CKD) is a rapidly growing, worldwide public health problem. Recent advances in genome-wide-association studies (GWAS) revealed several genetic loci associated with renal function traits worldwide.

METHODS

We investigated the association of genetic factors with the levels of serum creatinine (SCr) and the estimated glomerular filtration rate (eGFR) in Japanese population-based cohorts analyzing the GWAS imputed data with 11,221 subjects and 12,617,569 variants, and replicated the findings with the 148,829 hospital-based Japanese subjects.

RESULTS

In the discovery phase, 28 variants within 4 loci (chromosome [chr] 2 with 8 variants including rs3770636 in the LDL receptor related protein 2 gene locus, on chr 5 with 2 variants including rs270184, chr 17 with 15 variants including rs3785837 in the BCAS3 gene locus, and chr 18 with 3 variants including rs74183647 in the nuclear factor of -activated T-cells 1 gene locus) reached the suggestive level of p < 1 × 10-6 in association with eGFR and SCr, and 2 variants on chr 4 (including rs78351985 in the microsomal triglyceride transfer protein gene locus) fulfilled the suggestive level in association with the risk of CKD. In the replication phase, 25 variants within 3 loci (chr 2 with 7 variants, chr 17 with 15 variants and chr 18 with 3 variants) in association with eGFR and SCr, and 2 variants on chr 4 associated with the risk of CKD became nominally statistically significant after Bonferroni correction, among which 15 variants on chr 17 and 3 variants on chr 18 reached genome-wide significance of p < 5 × 10-8 in the combined study meta-analysis. The associations of the loci on chr 2 and 18 with eGFR and SCr as well as that on chr 4 with CKD risk have not been previously reported in the Japanese and East Asian populations.

CONCLUSION

Although the present GWAS of renal function traits included the largest sample of Japanese participants to date, we did not identify novel loci for renal traits. However, we identified the novel associations of the genetic loci on chr 2, 4, and 18 with renal function traits in the Japanese population, suggesting these are transethnic loci. Further investigations of these associations are expected to further validate our findings for the potential establishment of personalized prevention of renal disease in the Japanese and East Asian populations.

Genetic Variants of RAMP2 and CLR are Associated with Stroke

AIM

Stroke is associated closely with vascular homeostasis, and several complex processes and interacting pathways, which involve various genetic and environmental factors, contribute to the risk of stroke. Although adrenomedullin (ADM) has a number of physiological and vasoprotective functions, there are few studies of the ADM receptor system in humans. The ADM receptor comprises a calcitonin-receptor-like receptor (CLR) and receptor activity-modifying proteins (RAMPs). We analyzed single nucleotide polymorphisms (SNPs) in the RAMP2 and CLR genes to determine their association with stroke in the light of gene-environment interactions.

METHODS

Using cross-sectional data from the Japan Multi-Institutional Collaborative Cohort Study in the baseline surveys, 14,087 participants from 12 research areas were genotyped. We conducted a hypothesis-based association between stroke prevalence and SNPs in the RAMP2 and CLR genes based on data abstracted from two SNPs in RAMP2 and 369 SNPs in CLR. We selected five SNPs from among the CLR variants (rs77035639, rs3815524, rs75380157, rs574603859, and rs147565266) and one RAMP2 SNP (rs753152), which were associated with stroke, for analysis.

RESULTS

Five of the SNPs (rs77035639, rs3815524, rs75380157, rs147565266, and rs753152) showed no significant association with obesity, ischemic heart disease, hypertension, dyslipidemia, and diabetes. In the logistic regression analysis, rs574603859 had a lower odds ratio (0.238; 95% confidence interval, 0.076-0.745, adjusted for age, sex, and research area) and the other SNPs had higher odds ratios for association with stroke.

CONCLUSIONS

This was the first study to investigate the relationships between ADM receptor genes (RAMP2 and CLR) and stroke in the light of gene-environment interactions in human.