Dietary fiber intake and total and cause-specific mortality: the Japan Public Health Center-based prospective study

BACKGROUND

An inverse association has been shown between dietary fiber intake and several noncommunicable diseases. However, evidence of this effect remains unclear in the Asian population.

OBJECTIVE

We examined the association between dietary fiber intake and all-cause and cause-specific mortality, as well as the association between fiber intake from dietary sources and all-cause mortality.

METHODS

We conducted a large-scale population-based cohort study (Japan Public Health Center-based prospective study). A validated questionnaire with 138 food items was completed by 92,924 participants (42,754 men and 50,170 women) aged 45-74 y. Dietary fiber intake was calculated and divided into quintiles. HR and 95% CI of total and cause-specific mortality were reported.

RESULTS

During the mean follow-up of 16.8 y, 19,400 deaths were identified. In multivariable adjusted models, total, soluble, and insoluble fiber intakes were inversely associated with all-cause mortality. The HRs of total mortality in the highest quintile of total fiber intake compared with the lowest quintile were 0.77 (95% CI: 0.72, 0.82; Ptrend <0.0001) in men and 0.82 (95% CI: 0.76, 0.89; Ptrend <0.0001) in women. Increased quintiles of dietary fiber intake were significantly associated with decreased mortality due to total cardiovascular disease (CVD), respiratory disease, and injury in both men and women, whereas dietary fiber intake was inversely associated with cancer mortality in men but not women. Fiber from fruits, beans, and vegetables, but not from cereals, was inversely associated with total mortality.

CONCLUSION

In this large-scale prospective study with a long follow-up period, dietary fiber was inversely associated with all-cause mortality. Since intakes of dietary fiber, mainly from fruits, vegetables, and beans were associated with lower all-cause mortality, these food sources may be good options for people aiming to consume more fiber.

Associations between changes in fruit and vegetable consumption and weight change in Japanese adults

BACKGROUND

Fruits and vegetables may induce greater satiety, reduce hunger, decrease energy intake, and modulate energy metabolism, thereby playing a role in weight loss.

OBJECTIVE

To determine the associations between changes in fruit and vegetable consumption and weight change over a 5-year interval in Japanese adults.

METHODS

This cohort study included 54,015 subjects (54.6% female, mean age 56.5 years) of the Japan Public Health Center-based Prospective Cohort Study who had no known history of major chronic diseases at baseline. Data on fruit and vegetable consumption were collected using a validated food frequency questionnaire. Body weight was self-reported. We used multivariable linear mixed-effects regression models to examine the associations between changes in fruit and vegetable consumption and change in body weight.

RESULTS

On average, body weight decreased by 25 g [95% confidence interval (CI), 3, 47] for every 100 g/d increase in total vegetable consumption. Change in fruit consumption was nonlinearly associated with weight change. Fruit consumption was directly associated with weight change among subjects who increased consumption (70 g; 95% CI, 39, 101) but was not associated with weight change among subjects who reduced or did not change fruit consumption. These associations did not vary by sex, age, and body mass index (BMI) at baseline. The association with vegetables was restricted to yellow/red vegetables (- 74 g; 95% CI, - 129, - 18) and allium vegetables (- 129 g; 95% CI, - 231, - 28). Lower-fiber vegetables were inversely associated with weight change, whereas lower-fiber fruits or higher-energy fruits were directly associated with weight change beyond 0 g/d change in consumption.

CONCLUSIONS

Change in vegetable consumption was inversely associated with weight change while fruit consumption was positively associated with weight change among subjects who increased consumption. The influence of fruits and vegetables on weight change may depend on the characteristics of the fruits and vegetables.

Habitual tub bathing and risks of incident coronary heart disease and stroke

Objective

Tub bathing is considered to have a preventive effect against cardiovascular disease (CVD) by improving haemodynamic function. However, no prospective studies have investigated the long-term effects of tub bathing with regard to CVD risk.

Methods

A total of 30 076 participants aged 40–59 years with no history of CVD or cancer were followed up from 1990 to 2009. Participants were classified by bathing frequency: zero to two times/week, three to four times/week and almost every day. The HRs of incident CVD were estimated using Cox proportional hazards models after adjusting for traditional CVD risk factors and selected dietary factors.

Results

During 538 373 person-years of follow-up, we documented a total of 2097 incident cases of CVD, comprising 328 coronary heart diseases (CHDs) (275 myocardial infarctions and 53 sudden cardiac deaths) and 1769 strokes (991 cerebral infarctions, 510 intracerebral haemorrhages, 255 subarachnoid haemorrhages and 13 unclassified strokes). The multivariable HRs (95% CIs) for almost daily or every day versus zero to two times/week were 0.72 (0.62 to 0.84, trend p<0.001) for total CVD; 0.65 (0.45 to 0.94, trend p=0.065) for CHD; 0.74 (0.62 to 0.87, trend p=0.005) for total stroke; 0.77 (0.62 to 0.97, trend p=0.467) for cerebral infarction; and 0.54 (0.40 to 0.73, trend p<0.001) for intracerebral haemorrhage. No associations were observed between tub bathing frequency and risk of sudden cardiac death or subarachnoid haemorrhage.

Conclusion

The frequency of tub bathing was inversely associated with the risk of CVD among middle-aged Japanese.

Green tea (Camellia sinensis) for the prevention of cancer

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (2009, Issue 3).Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia sinensis can be grouped into green, black and oolong tea, and drinking habits vary cross-culturally. C sinensis contains polyphenols, one subgroup being catechins. Catechins are powerful antioxidants, and laboratory studies have suggested that these compounds may inhibit cancer cell proliferation. Some experimental and nonexperimental epidemiological studies have suggested that green tea may have cancer-preventative effects.

OBJECTIVES

To assess possible associations between green tea consumption and the risk of cancer incidence and mortality as primary outcomes, and safety data and quality of life as secondary outcomes.

SEARCH METHODS

We searched eligible studies up to January 2019 in CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and reference lists of previous reviews and included studies.

SELECTION CRITERIA

We included all epidemiological studies, experimental (i.e. randomised controlled trials (RCTs)) and nonexperimental (non-randomised studies, i.e. observational studies with both cohort and case-control design) that investigated the association of green tea consumption with cancer risk or quality of life, or both.

DATA COLLECTION AND ANALYSIS

Two or more review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. We summarised the results according to diagnosis of cancer type.

MAIN RESULTS

In this review update, we included in total 142 completed studies (11 experimental and 131 nonexperimental) and two ongoing studies. This is an additional 10 experimental and 85 nonexperimental studies from those included in the previous version of the review. Eleven experimental studies allocated a total of 1795 participants to either green tea extract or placebo, all demonstrating an overall high methodological quality based on 'Risk of bias' assessment. For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence). The summary RR for gynaecological cancer was 1.50 (95% CI 0.41 to 5.48; 2 studies, 1157 participants; low-certainty evidence). No evidence of effect of non-melanoma skin cancer emerged (summary RR 1.00, 95% CI 0.06 to 15.92; 1 study, 1075 participants; low-certainty evidence). In addition, adverse effects of green tea extract intake were reported, including gastrointestinal disorders, elevation of liver enzymes, and, more rarely, insomnia, raised blood pressure and skin/subcutaneous reactions. Consumption of green tea extracts induced a slight improvement in quality of life, compared with placebo, based on three experimental studies. In nonexperimental studies, we included over 1,100,000 participants from 46 cohort studies and 85 case-control studies, which were on average of intermediate to high methodological quality based on Newcastle-Ottawa Scale 'Risk of bias' assessment. When comparing the highest intake of green tea with the lowest, we found a lower overall cancer incidence (summary RR 0.83, 95% CI 0.65 to 1.07), based on three studies, involving 52,479 participants (low-certainty evidence). Conversely, we found no association between green tea consumption and cancer-related mortality (summary RR 0.99, 95% CI 0.91 to 1.07), based on eight studies and 504,366 participants (low-certainty evidence). For most of the site-specific cancers we observed a decreased RR in the highest category of green tea consumption compared with the lowest one. After stratifying the analysis according to study design, we found strongly conflicting results for some cancer sites: oesophageal, prostate and urinary tract cancer, and leukaemia showed an increased RR in cohort studies and a decreased RR or no difference in case-control studies.

AUTHORS' CONCLUSIONS

Overall, findings from experimental and nonexperimental epidemiological studies yielded inconsistent results, thus providing limited evidence for the beneficial effect of green tea consumption on the overall risk of cancer or on specific cancer sites. Some evidence of a beneficial effect of green tea at some cancer sites emerged from the RCTs and from case-control studies, but their methodological limitations, such as the low number and size of the studies, and the inconsistencies with the results of cohort studies, limit the interpretability of the RR estimates. The studies also indicated the occurrence of several side effects associated with high intakes of green tea. In addition, the majority of included studies were carried out in Asian populations characterised by a high intake of green tea, thus limiting the generalisability of the findings to other populations. Well conducted and adequately powered RCTs would be needed to draw conclusions on the possible beneficial effects of green tea consumption on cancer risk.

Genome-Wide Polygenic Score and the Risk of Ischemic Stroke in a Prospective Cohort

Background and Purpose—

Environmental and genetic factors contribute to the development of ischemic stroke (IS). We recently developed a genome-wide polygenic risk score (PRS) for IS using case-control datasets from 4 large-scale observational studies conducted in Japan. Our objective in the present study was to confirm the association between the PRS and the risk of IS with data from an independent prospective cohort recruited from the general Japanese population.

Methods—

A total of 3038 subjects aged ≥40 years were followed up for 10 years (2002–2012). The genome-wide PRS was calculated using genotype data from >350 000 single-nucleotide polymorphisms. The PRS levels were divided into quintiles. High and low genetic risk groups were defined as top 60% and bottom 40% of PRS, respectively. The hazard ratio (HR) for the development of IS was estimated using a Cox proportional hazards model.

Results—

During the follow-up period, 91 cases developed first-ever IS. The age- and sex-adjusted HR for IS increased with higher PRS levels ( P for trend, 0.03). Subjects with the highest quintile level of PRS had a 2.44-fold (95% CI, 1.16–5.12) greater risk for IS than those with the lowest quintile level after adjusting for age and sex. A similar association was observed after adjusting for environmental risk factors ( P for trend, 0.03). As compared with low genetic risk group, the age- and sex-adjusted HR in high genetic risk group was 1.63 (95% CI, 1.04–2.55), which was comparable to the HR of hypertension (HR, 1.41), diabetes mellitus (HR, 1.72), and smoking (HR, 1.54). The age- and sex-adjusted HR increased with the number of environmental risk factors in both high and low genetic risk groups without significant interaction.

Conclusions—

A high genome-wide PRS was a significant risk factor for IS independent of environmental risk factors in a general Japanese population. This finding suggests that PRS may be useful to identify individuals at a high risk of IS.

Fat mass and obesity-associated gene polymorphisms, pre-diagnostic plasma adipokine levels and the risk of colorectal cancer: The Japan Public Health Center-based Prospective Study

Although their functional outcomes remain largely unknown, single nucleotide polymorphisms (SNPs) in the fat mass and obesity-associated gene (FTO) may interact with adipokines, especially leptin and adiponectin, to modify the risk of colorectal cancer. We conducted a prospective study of 375 colorectal cancer cases and 750 matched controls to examine the effects of SNPs in the FTO, either alone or in interaction with pre-diagnostic plasma adipokine levels. Using a conditional logistic regression model, we obtained odds ratios (ORs) and their 95% confidence intervals (CIs) of colorectal cancer. Seven SNPs in strong linkage disequilibrium demonstrated a similarly positive association with colorectal cancer, and most evidently for rs1558902, rs8050136, rs3751812, and rs9939609 (Ptrend = 0.02). Of interest, we observed a statistically significant interaction of rs8050136 with plasma total adiponectin levels (Pinteraction = 0.03). Compared to non-carriers in the lowest quintile of plasma total adiponectin, A allele carriers in the same quintile showed a considerably elevated risk of colorectal cancer, with a body mass index-adjusted OR of 2.54 (95% CI, 1.36-4.75). This investigation of the interaction between SNPs in the FTO and pre-diagnostic plasma adipokine levels has revealed the importance of both genetic and hormonal factors associated with adiposity in colorectal carcinogenesis.

Impact of alcohol drinking on cancer risk with consideration of flushing response: The Japan Public Health Center-based Prospective Study Cohort (JPHC study)

Alcohol drinking is a risk factor for cancer. The degree of risk is increased in subjects showing the flushing response, which is due to aldehyde dehydrogenase 2 (ALDH2) polymorphism. The attributable risk of alcohol drinking for cancer in Japan has not been sufficiently investigated with consideration of flushing response. We followed 78,825 Japanese in JPHC study cohort II. The association between alcohol consumption and cancer incidence was assessed according to self-reported flushing response using Cox proportional hazards regression models. The population-attributable fraction (PAF) of cancer incidence was also estimated. During 1993-2013 (average follow-up, 16.8 years), 8486 incident cancers (included 4386 alcohol-related cancers) were reported. Half of men and 36% of women had flushing response. In men with flushing response, moderate or higher alcohol drinking increased the risk of alcohol-related cancers compared with non-drinkers (150-299 g/week, HR 1.63, 95% CI, 1.43-1.99; 300-449 g/week, HR 2.02 95% CI, 1.67-2.44; ≥450 g/week, HR 1.75, 95% CI, 1.39-2.21). When flushing response was considered in comparisons between non-drinkers and non-flushers, non-flushing heavy drinkers had a slightly higher PAF than flushers (all cancers: flushers, 2.0% and non-flushers, 2.2%; alcohol-related cancers: flushers, 3.8% and non-flushers, 5.8%). Although the risk of alcohol-related cancer in men with flushing response increased with increasing alcohol consumption, heavy drinkers were also at high risk regardless of flushing response. Considering the PAF of alcohol consumption on cancer, efforts to discourage heavy alcohol consumption to reduce the incidence of alcohol-related cancers appear warranted regardless of flushing response.

Coffee, green tea and liver cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population

BACKGROUND

Coffee and green tea, two popular drinks in the Japanese, have recently drawn much attention as potential protective factors against the occurrence of liver cancer.

METHODS

We systematically reviewed epidemiologic studies on coffee, green tea and liver cancer among Japanese populations. Original data were obtained by searching the MEDLINE (PubMed) and Ichushi databases, complemented with manual searches. The evaluation was performed in terms of the magnitude of association in each study and the strength of evidence ('convincing', 'probable', 'possible', or 'insufficient'), together with biological plausibility.

RESULTS

We identified four cohort and four case-control studies on coffee and liver cancer and six cohort and one case-control studies on green tea and liver cancer. All cohort and case-control studies on coffee reported a weak to strong inverse association, with a summary relative risk (RR) for one cup increase being 0.72 (95% confidence interval [CI] 0.66-0.79). Conversely, all studies but two cohort studies on green tea reported no association, with a corresponding summary RR of 0.99 (95% CI 0.97-1.01, P = 0.37).

CONCLUSION

Coffee drinking 'probably' decreases the risk of primary liver cancer among the Japanese population whereas the evidence on an association between green tea and liver cancer is 'insufficient' in this population.

Occupational sitting time and subsequent risk of cancer: The Japan Public Health Center-based Prospective Study

Although occupational sitting time has been associated with adverse health outcomes and mortality, the association with cancer incidence remains unknown. This study investigated the association between occupational sitting time and risk of total and site‐specific cancer in a Japanese population. We evaluated 33 307 participants aged 50‐79 years who responded to a questionnaire in 2000‐2003 in the Japan Public Health Center‐based Prospective Study and were followed until 2013. Participants were grouped by sitting time at work. Hazard ratio (HR) and 95% confidence interval (CI) of cancer incidence were calculated with adjustment for potential confounders including moderate‐to‐vigorous physical activity. During 10.2 years of follow‐up, 3807 newly diagnosed cases of cancer were identified. Occupational sitting time was marginally associated with total cancer, with multivariable HRs for the ≥7 h/d vs 1 to <3 h/d category of 1.12 (95% CI, 0.99‐1.26; P for trend = .071) in men, but not women. Among findings for cancers at specific sites, long occupational sitting time was associated with increased risk of pancreas cancer, with multivariable HRs for the ≥7 h/d vs 1 to <3 h/d category of 2.25 (95% CI, 1.17‐4.34; P for trend = .021) in men, and lung cancer, with multivariable HRs for the ≥7 h/d vs 1 to <3 h/d category of 2.80 (95% CI, 1.33‐5.90; P for trend = .013) in women. Extended sitting time at work was associated with an increased risk of pancreas cancer in men and lung cancer in women.

Significance of the gut microbiome in multistep colorectal carcinogenesis

Colorectal cancer (CRC) is highly prevalent worldwide. In 2018, there were over 1.8 million new cases. Most sporadic CRC develop from polypoid adenomas and are preceded by intramucosal carcinoma (stage 0), which can progress into more malignant forms. This developmental process is known as the adenoma-carcinoma sequence. Early detection and endoscopic removal are crucial for CRC management. Accumulating evidence suggests that the gut microbiota is associated with CRC development in humans. Comprehensive characterization of this microbiota is of great importance to assess its potential as a diagnostic marker in the very early stages of CRC. In this review, we summarized recent studies on CRC-associated bacteria and their carcinogenic mechanisms in animal models, human cell lines and human cohorts. High-throughput technologies have facilitated the identification of CRC-associated bacteria in human samples. We have presented our metagenome and metabolome studies on fecal samples collected from a large Japanese cohort that revealed stage-specific phenotypes of the microbiota in CRC. Furthermore, we have discussed the potential carcinogenic mechanisms of the gut microbiota, from which we can infer whether changes in the gut microbiota are a cause or effect in the multi-step process of CRC carcinogenesis.

Association of soy and fermented soy product intake with total and cause specific mortality: prospective cohort study

OBJECTIVE

To investigate the association between several types of soy products and all cause and cause specific mortality.

DESIGN

Population based cohort study.

SETTING

Japan Public Health Centre-based Prospective Study, which includes 11 public health centre areas in Japan.

PARTICIPANTS

92 915 participants (42 750 men and 50 165 women) aged 45 to 74 years.

EXPOSURES

Intake of total soy products, fermented soy products (natto and miso), non-fermented soy products, and tofu from a five year survey questionnaire.

MAIN OUTCOME MEASURES

All cause and cause specific mortality (cancer, total cardiovascular disease, heart disease, cerebrovascular disease, respiratory disease, and injury) obtained from residential registries and death certificates.

RESULTS

During 14.8 years of follow-up, 13 303 deaths were identified. In the multivariable adjusted models, intake of total soy products was not significantly associated with total mortality. Compared with the lowest fifth of total soy product intake, the hazard ratios in the highest fifth were 0.98 (95% confidence interval 0.91 to 1.06, P_trend=0.43) in men and 0.98 (0.89 to 1.08, P_trend=0.46) in women. Intake of fermented soy products was inversely associated with all cause mortality in both sexes (highest versus lowest fifth: 0.90 (0.83 to 0.97), P_trend=0.05 in men, and 0.89 (0.80 to 0.98), P_trend=0.01 in women). Natto showed significant and inverse associations with total cardiovascular disease related mortality in both sexes.

CONCLUSIONS

In this study a higher intake of fermented soy was associated with a lower risk of mortality. A significant association between intake of total soy products and all cause mortality was not, however, observed. The findings should be interpreted with caution because the significant association of fermented soy products might be attenuated by unadjusted residual confounding.

Identification of a novel uterine leiomyoma GWAS locus in a Japanese population

Uterine leiomyoma is one of the most common gynaecologic benign tumours, but its genetic basis remains largely unknown. Six previous GWAS identified 33 genetic factors in total. Here, we performed a two-staged GWAS using 13,746 cases and 70,316 controls from the Japanese population, followed by a replication analysis using 3,483 cases and 4,795 controls. The analysis identified 9 significant loci, including a novel locus on 12q23.2 (rs17033114, P = 6.12 × 10^-25 with an OR of 1.177 (1.141-1.213), LINC00485). Subgroup analysis indicated that 5 loci (3q26.2, 5p15.33, 10q24.33, 11p15.5, 13q14.11) exhibited a statistically significant effect among multiple leiomyomas, and 2 loci (3q26.2, 10q24.33) exhibited a significant effect among submucous leiomyomas. Pleiotropic analysis indicated that all 9 loci were associated with at least one proliferative disease, suggesting the role of these loci in the common neoplastic pathway. Furthermore, the risk T allele of rs2251795 (3q26.2) was associated with longer telomere length in both normal and tumour tissues. Our findings elucidated the significance of genetic factors in the pathogenesis of leiomyoma.

GWAS of 165,084 Japanese individuals identified nine loci associated with dietary habits

Dietary habits are important factors in our lifestyle, and confer both susceptibility to and protection from a variety of human diseases. We performed genome-wide association studies for 13 dietary habits including consumption of alcohol (ever versus never drinkers and drinks per week), beverages (coffee, green tea and milk) and foods (yoghurt, cheese, natto, tofu, fish, small whole fish, vegetables and meat) in Japanese individuals (n = 58,610-165,084) collected by BioBank Japan, the nationwide hospital-based genome cohort. Significant associations were found in nine genetic loci (MCL1-ENSA, GCKR, AGR3-AHR, ADH1B, ALDH1B1, ALDH1A1, ALDH2, CYP1A2-CSK and ADORA2A-AS1) for 13 dietary traits (P < 3.8 × 10^-9). Of these, ten associations between five loci and eight traits were new findings. Furthermore, a phenome-wide association study revealed that five of the dietary trait-associated loci have pleiotropic effects on multiple human complex diseases and clinical measurements. Our findings provide new insight into the genetics of habitual consumption.

Intake of Vegetables and Fruits and the Risk of Cataract Incidence in a Japanese Population: The Japan Public Health Center-Based Prospective Study

Background

Although the consumption of vegetables and fruits is reported to influence the risk of cataract, no prospective study of this association from Asia has yet appeared. Here, we investigated the association between vegetable and fruit intake and cataract incidence in a large-scale population-based prospective cohort study in Japan.

Methods

This study included 32,387 men and 39,333 women aged 45–74 years who had no past history of cataract and had completed a dietary questionnaire of the Japan Public Health Center-based Prospective Cohort Study. The incidence of cataract was evaluated after 5-year follow-up. We used multiple logistic regression analyses to estimate the sex-specific odds ratios (ORs), with adjustment for confounding factors.

Results

We identified 1,836 incident cataracts in 594 men and 1,242 women. In men, the OR for cataract was decreased with higher intake of vegetables (OR_{Q5 vs Q1}, 0.77; 95% confidence interval [CI], 0.59–1.01; P_trend across quartile categories = 0.03) and cruciferous vegetables (OR_{Q5 vs Q1}, 0.74; 95% CI, 0.57–0.96; P_trend = 0.02). In contrast, the OR for cataract was increased with higher intake of vegetables among women (OR_{Q5 vs Q1}, 1.28; 95% CI, 1.06–1.53; P_trend = 0.01). Green and yellow vegetable and fruit intake were not associated with cataract in either sex.

Conclusions

This study suggests that vegetables may reduce the risk of cataract in men, but not in women.

The U-shaped association between body mass index and gastric cancer risk in the Helicobacter pylori Biomarker Cohort Consortium: A nested case-control study from eight East Asian cohort studies

The association between body mass index (BMI) and noncardia gastric cancer (NCGC) risk remains controversial. The purpose of our study was to examine the association of BMI with NCGC risk with consideration of Helicobacter pylori (HP) biomarkers. This international nested case-control study, composed of 1,591 incident NCGC cases and 1,953 matched controls, was established from eight cohorts in China, Japan and Korea, where the majority of NCGCs are diagnosed worldwide. HP antibody biomarkers were measured in blood collected at cohort enrollment by multiplex serology. The NCGC risk according to baseline BMI was estimated using logistic regression to produce odds ratios (ORs) and 95% confidence intervals (CIs). We found a U-shaped association between BMI category and NCGC risk. Compared to those with reference BMI (22.6-25.0 kg/m² ), those with lower and higher BMI had an increased NCGC risk (BMI <18.5 kg/m² , OR = 1.56, 95% CI = 1.04-2.34; BMI >27.5 kg/m² , OR = 1.48, 95% CI = 1.15-1.91; adjusted for age, sex and smoking). The U-shaped association was persistent among subjects with HP infection and high-risk biomarkers (HP+ CagA+: BMI <18.5 kg/m² , OR = 1.60, 95% CI = 1.00-2.55; BMI >27.5 kg/m² , OR = 1.59, 95% CI = 1.21-2.11; and Omp+ HP0305+: BMI <18.5 kg/m² , OR = 1.88, 95% CI = 1.04-3.42; BMI >27.5 kg/m² , OR = 1.70, 95% CI = 1.20-2.42, respectively). Our study provides evidence of significantly increased NCGC risk among individuals with low or high BMI, including in subjects with high-risk HP biomarkers (HP+ CagA+, Omp+ HP0305+) in the high-risk area of East Asia.

Smoking, Alcohol, and Biliary Tract Cancer Risk: A Pooling Project of 26 Prospective Studies

BACKGROUND

Tobacco and alcohol are well-established risk factors for numerous cancers, yet their relationship to biliary tract cancers remains unclear.

METHODS

We pooled data from 26 prospective studies to evaluate associations of cigarette smoking and alcohol consumption with biliary tract cancer risk. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for associations with smoking and alcohol consumption were calculated. Random-effects meta-analysis produced summary estimates. All statistical tests were two-sided.

RESULTS

Over a period of 38 369 156 person-years of follow-up, 1391 gallbladder, 758 intrahepatic bile duct, 1208 extrahepatic bile duct, and 623 ampulla of Vater cancer cases were identified. Ever, former, and current smoking were associated with increased extrahepatic bile duct and ampulla of Vater cancers risk (eg, current vs never smokers HR = 1.69, 95% CI = 1.34 to 2.13 and 2.22, 95% CI = 1.69 to 2.92, respectively), with dose-response effects for smoking pack-years, duration, and intensity (all Ptrend < .01). Current smoking and smoking intensity were also associated with intrahepatic bile duct cancer (eg, >40 cigarettes per day vs never smokers HR = 2.15, 95 % CI = 1.15 to 4.00; Ptrend = .001). No convincing association was observed between smoking and gallbladder cancer. Alcohol consumption was only associated with intrahepatic bile duct cancer, with increased risk for individuals consuming five or more vs zero drinks per day (HR = 2.35, 95%CI = 1.46 to 3.78; Ptrend = .04). There was evidence of statistical heterogeneity among several cancer sites, particularly between gallbladder cancer and the other biliary tract cancers.

CONCLUSIONS

Smoking appears to increase the risk of developing all biliary tract cancers except gallbladder cancer. Alcohol may increase the risk of intrahepatic bile duct cancer. Findings highlight etiologic heterogeneity across the biliary tract.

Seaweed intake and risk of cardiovascular disease: the Japan Public Health Center-based Prospective (JPHC) Study

BACKGROUND

The minerals, vitamins, soluble dietary fibers, and flavonoids of seaweed are protective for preventing cardiovascular diseases. However, the association between seaweed intake and risk of cardiovascular disease has not been established.

OBJECTIVES

We examined the dietary intake of seaweed and its impact upon stroke and ischemic heart disease risk among a Japanese study population.

METHODS

We surveyed 40,707 men and 45,406 women from 2 large cohorts (age range: 40-69 y). Seaweed intake was determined by FFQ at baseline (1990-1994). Incidences of stroke and ischemic heart disease were ascertained until the end of 2009 (Cohort I) or 2012 (Cohort II). Sex-specific cardiovascular disease HRs (95% CIs) were estimated using Cox proportional hazard models after stratification by area and adjustment for cardiovascular disease risk and dietary factors.

RESULTS

During 1,493,232 person-years of follow-up, 4777 strokes (2863 ischemic stroke, 1361 intraparenchymal hemorrhages, and 531 subarachnoid hemorrhages) and 1204 ischemic heart disease cases were identified. Among men, significant multivariable HRs (95% CIs) for almost daily consumption compared with almost no consumption of seaweed were seen in ischemic heart disease [0.76 (0.58, 0.99); P-trend = 0.04] and total cardiovascular diseases [0.88 (0.78, 1.00); P-trend = 0.08]. Among women, such inverse associations were 0.56 (0.36, 0.85; P-trend = 0.006) for ischemic heart disease and 0.89 (0.76, 1.05; P-trend = 0.10) for total cardiovascular diseases. No significant associations were observed between seaweed intake and risk of total stroke or stroke types among either men or women.

CONCLUSIONS

Seaweed intake was inversely associated with risk of ischemic heart disease.

Identification of two novel breast cancer loci through large-scale genome-wide association study in the Japanese population

Genome-wide association studies (GWAS) have successfully identified about 70 genomic loci associated with breast cancer. Owing to the complexity of linkage disequilibrium and environmental exposures in different populations, it is essential to perform regional GWAS for better risk prediction. This study aimed to investigate the genetic architecture and to assess common genetic risk model of breast cancer with 6,669 breast cancer patients and 21,930 female controls in the Japanese population. This GWAS identified 11 genomic loci that surpass genome-wide significance threshold of P < 5.0 × 10⁻⁸ with nine previously reported loci and two novel loci that include rs9862599 on 3q13.11 (ALCAM) and rs75286142 on 21q22.12 (CLIC6-RUNX1). Validation study was carried out with 981 breast cancer cases and 1,394 controls from the Aichi Cancer Center. Pathway analyses of GWAS signals identified association of dopamine receptor medicated signaling and protein amino acid deacetylation with breast cancer. Weighted genetic risk score showed that individuals who were categorized in the highest risk group are approximately 3.7 times more likely to develop breast cancer compared to individuals in the lowest risk group. This well-powered GWAS is a representative study to identify SNPs that are associated with breast cancer in the Japanese population.

Relationship between Meat/Fish Consumption and Biliary Tract Cancer: The Japan Public Health Center-Based Prospective Study

BACKGROUND

The effect of meat and fish consumption on cancer risk has been well studied in humans. However, studies related to biliary tract cancer (BTC) are scarce.

METHODS

We examined the association between meat and fish consumption and the risk of BTC in a population-based prospective cohort study in Japan. HRs and 95% confidence intervals (CI) were estimated using the Cox proportional hazard model.

RESULTS

During 1995 and 1999, 43,177 men and 49,323 women ages 45 to 74 years were enrolled and followed up for 607,757.0 person-years (men) and 728,820.3 person-years (women) until 2012, during which time 217 male and 162 female BTC cases were identified. Higher total meat consumption was significantly associated with a decreased BTC risk in men (HR for the highest vs. lowest quartiles = 0.66; 95% CI, 0.44-0.98; P _trend = 0.011) but not in women. Similar association was observed with red meat, but no association was observed with poultry. Fish was not associated with BTC risk. We further analyzed each BTC subtype to confirm the observed association with BTC. However, significant association with each BTC subtype was not observed, although a trend of decreased extrahepatic bile duct cancer risk was observed.

CONCLUSIONS

BTC risk was lower among men who consumed more meat, particularly red meat, in Japan.

IMPACT

This is the first prospective study that evaluated the relationship between meat and BTC. This may provide important suggestions to elucidate the etiology of BTC.

Female reproductive factors and risk of external causes of death among women: The Japan Public Health Center-based Prospective Study (JPHC Study)

Although empirical data suggest a possible link between female reproductive events and risk of nonfatal accidents and suicidal behaviors, evidence to determine these effects on mortality is scarce. This study investigated the association between female reproductive factors and the risk of external causes of death among middle-aged Japanese women. We used a population-based cohort study consisting of 71 698 women residing in 11 public health center areas across Japan between 1990 and 1994. Multivariable-adjusted Cox proportional hazard regression models were used to estimate hazard ratios (HRs) of the risk of all external causes, suicide, and accidents according to female reproductive factors at the baseline survey. During 1 028 583 person-years of follow-up for 49 279 eligible subjects (average 20.9 years), we identified 328 deaths by all injuries. Among parous women, ever versus never breastfeeding [0.67 (95% CI: 0.49–0.92)] was associated with a decreased risk of all injuries. Risk of suicide was inversely associated with ever versus never parity [0.53 (95% CI: 0.32–0.88)]. A lower risk of death by accidents was seen in ever breastfeeding [0.63 (95% CI: 0.40–0.97)] compared to never breastfeeding. This study suggests that parity and breastfeeding are associated with reduced risk of death by all external causes, suicide and/or accidents among Japanese women.

Revisit of an unanswered question by pooled analysis of eight cohort studies in Japan: Does cigarette smoking and alcohol drinking have interaction for the risk of esophageal cancer?

Cigarette smoking and alcohol drinking are two major risk factors for esophageal cancer. Not all, but several of case-control studies have indicated interaction between the two factors; however, no prospective study has validated this phenomenon to date. Therefore, the interaction between smoking and alcohol drinking is still open-ended question. To answer this, we conducted a pooled analysis using large-scale population-based cohort studies in Japan. Male subjects from eight cohort studies were included. Cigarette smoking and alcohol drinking were both categorized categorically (never/ever), and in the three consumption levels of pack years and ethanol consumption/day. Effects of smoking and drinking in each study were estimated by Cox regression models. The study-specific results were combined through meta-analysis to obtain summary effects of hazard ratios (HRs) and measures of interactions at both additive and multiplicative scales. Population attributable fractions (PAFs) from smoking and drinking were obtained using distributions of exposures and fully adjusted HRs. In 162 826 male subjects, 954 esophageal cancer incidences were identified. HRs of ever smoking, ever drinking, and their combination were 2.92 (1.59-5.36), 2.73 (1.78-4.18), and 8.86 (4.82-16.30), respectively. Interaction between cigarette smoking and alcohol drinking was significantly positive on the additive scale, but not significant on the multiplicative scale. The joint effect of smoking and drinking in three levels of evaluation showed a similar significant super-additive interaction. PAFs from smoking, drinking, and their combination were 55.4%, 61.2%, and 81.4%, respectively. Cigarette smoking and alcohol drinking had a significant positive additive interaction for esophageal cancer risk.

12 new susceptibility loci for prostate cancer identified by genome-wide association study in Japanese population

Genome-wide association studies (GWAS) have identified ~170 genetic loci associated with prostate cancer (PCa) risk, but most of them were identified in European populations. We here performed a GWAS and replication study using a large Japanese cohort (9,906 cases and 83,943 male controls) to identify novel susceptibility loci associated with PCa risk. We found 12 novel loci for PCa including rs1125927 (TMEM17, P = 3.95 × 10⁻¹⁶), rs73862213 (GATA2, P = 5.87 × 10⁻²³), rs77911174 (ZMIZ1, P = 5.28 × 10⁻²⁰), and rs138708 (SUN2, P = 1.13 × 10⁻¹⁵), seven of which had crucially low minor allele frequency in European population. Furthermore, we stratified the polygenic risk for Japanese PCa patients by using 82 SNPs, which were significantly associated with Japanese PCa risk in our study, and found that early onset cases and cases with family history of PCa were enriched in the genetically high-risk population. Our study provides important insight into genetic mechanisms of PCa and facilitates PCa risk stratification in Japanese population.

More than 170 genetic loci have been linked to prostate cancer risk, primarily based on genome-wide association studies (GWAS) in European population. Here, the authors performed a GWAS on a Japanese cohort of prostate cancer patients, finding 12 new susceptibility loci, and identifying a polygenic risk for Japanese prostate cancer.

Non-High-Density Lipoprotein Cholesterol and Risk of Stroke Subtypes and Coronary Heart Disease: The Japan Public Health Center-Based Prospective (JPHC) Study

Aim: A positive association between non-high-density lipoprotein cholesterol (non-HDL-C) and coronary heart disease (CHD) has been established; however, associations between non-HDL-C and stroke subtypes have not been determined.

Methods: We conducted a prospective study of 30,554 individuals aged 40–69 yrs with no history of cardiovascular disease (CVD) in Japan. Sex-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for the incidence of stroke subtypes and CHD were estimated according to quintiles of non-HDL-C, using Cox proportional hazard models adjusted for other established risk factors.

Results: We identified 1,705 stroke and 296 CHD events over a median 15 yrs of follow-up. The fractional polynomials analysis revealed a U-shaped association between non-HDL-C and stroke risk in men. When analyzed for stroke subtypes, the data revealed an inverse relationship between non-HDL-C and intracerebral hemorrhage (ICH), primarily with lobar ICH, and a positive association between non-HDL-C and large-artery occlusive infarction in men [adjusted HR 0.55 (95% CI, 0.35–0.87) and 2.05 (95% CI, 1.07–3.93) for the highest and lowest quintile of non-HDL-C, respectively]. The lowest risk of ICH in women was observed in the fourth quintile, and the lowest risk of embolic infarction was observed in the third quintile. In contrast, non-HDL-C was positively associated with CHD in both sexes.

Conclusions: In Japanese men, lower non-HDL-C levels were associated with a decreased risk of large-artery occlusive infarction and an increased risk of ICH, particularly lobar ICH.

Higher Dietary Non-enzymatic Antioxidant Capacity Is Associated with Decreased Risk of All-Cause and Cardiovascular Disease Mortality in Japanese Adults

BACKGROUND

Few studies have assessed associations of non-enzymatic antioxidant capacity (NEAC) in the overall diet with all-cause or specific mortality, and their results have been inconsistent.

OBJECTIVES

The present study investigated the association between dietary NEAC and all-cause or cause-specific mortality.

METHODS

The study was a large-scale population-based prospective cohort study in Japan consisting of 42,520 men and 50,207 women aged 44-76 y, who had no history of cancer, stroke, ischemic heart disease, or chronic liver disease. We evaluated FFQ-based dietary NEAC with use of published databases in which the NEACs of individual foods were analyzed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Dietary NEAC was calculated by multiplying the estimated NEAC with the consumed amount and summing up those values for all foods, and was categorized in quartiles. We identified death and cause of death with use of residential registry and death certificates. HRs and 95% Cls for death from the second survey, which was conducted from April 1995 to December 2014 were estimated with Cox proportional hazards regression analysis.

RESULTS

After 1,498,308 person-years of follow-up, 12,978 total deaths occurred. The multivariable-adjusted HRs (95% Cls) for all-cause mortality for the highest compared with the lowest quartile of FRAP and ORAC were 0.85 (0.80, 0.89) and 0.84 (0.79, 0.89), respectively. Dietary NEACs were inversely associated with mortality from cardiovascular disease (CVD), but not from cancer. The multivariable-adjusted HRs (95% Cls) for CVD for the highest compared with the lowest quartile of FRAP and ORAC were 0.83 (0.75, 0.92) and 0.79 (0.70, 0.89), respectively.

CONCLUSIONS

Higher dietary NEACs from FRAP and ORAC were associated with lower risk of all-cause mortality and mortality from CVD in Japanese adults.

Circulating sex hormone levels and colorectal cancer risk in Japanese postmenopausal women: The JPHC nested case-control study

Previous epidemiological studies evaluated endogenous sex hormone levels and colorectal cancer (CRC) risk have yielded inconsistent results. Also, it is unknown if consumption of dietary isoflavones may influence the endogenous sex hormones and CRC relationships. We conducted a nested case-control study within the JPHC Study Cohort II wherein 11,644 women provided blood samples at the 5-year follow-up survey. We selected two matched controls for each case from the cohort (185 CRC cases and 361 controls). Multivariable conditional logistic regression was used to estimate odds ratios (ORs), 95% confidence intervals (CIs) for the association between circulating sex hormone levels and CRC risk. Comparing extreme tertiles, circulating testosterone levels were positively associated with CRC risk (OR = 2.10, 95% CI = 1.11-3.99, p for trend = 0.03). Levels of estradiol, SHBG, and progesterone were not associated with CRC risk. In a subgroup analysis by dietary isoflavone intake, SHBG levels were positively associated with CRC risk among those with low total isoflavone intake (p for trend = 0.03), with a statistically nonsignificant inverse association among those with high total isoflavone intake (p for trend = 0.22; p for interaction = 0.002). Endogenous levels of testosterone were positively associated with CRC among postmenopausal women. The association of endogenous SHBG with CRC development may be altered by the level of dietary isoflavone intake.

Association of BMI and height with the risk of endometrial cancer, overall and by histological subtype: a population-based prospective cohort study in Japan

Evidence on the association between BMI, height, and endometrial cancer risk, including by subtypes, among Asian populations remains limited. We evaluated the impact of BMI and height on the risk of endometrial cancer, overall and by histological subtype. We prospectively investigated 53 651 Japanese women aged 40-69 years. With an average follow-up duration of 18.6 years, 180 newly diagnosed endometrial cancers were reported, including 119 type 1 and 21 type 2. The association between BMI, height, and endometrial cancer risk was assessed using a Cox proportional hazards regression model with adjustment for potential confounders. Overweight and obesity were associated positively with the risk of endometrial cancer. Compared with BMI of 23.0-24.9 kg/m, hazard ratios (HRs) (95% confidence intervals) were 1.93 (1.17-3.16) for BMI of 27.0-29.9 kg/m and 2.37 (1.20-4.66) for BMI of at least 30.0 kg/m. On analysis by histological subtype, with each increase in BMI of 5 U, the estimated HR of type 1 endometrial cancer increased (HR=1.54, 95% confidence interval: 1.21-1.98), but HR of type 2 endometrial cancer was unaffected. There was no statistically significant association between height and endometrial cancer risk. In conclusion, the risk of endometrial cancer was elevated in women with a BMI of at least 27.0 kg/m. By histological subtype, BMI was associated with type 1, but not type 2 endometrial cancer risk among a population with a relatively low BMI compared with western populations.

Association between serum liver enzymes and all-cause mortality: The Japan Public Health Center-based Prospective Study

BACKGROUND & AIMS

The association of serum liver enzyme levels with all-cause mortality in individuals without hepatitis B virus or hepatitis C virus infection is inconsistent. We aimed to investigate all-cause and non-liver disease mortality according to levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT) stratified by hepatitis virus infection status in a Japanese cohort.

METHODS

Participants were 7243 men and 13 513 women aged 40-69 years at the baseline survey in 1993-1994. Multivariate-adjusted hazard ratios of death from the baseline health check-up to December 2012 were calculated with a Cox proportional hazards model controlling for potential confounding factors.

RESULTS

During follow-up, 2235 deaths in men and 1901 deaths in women were identified. All serum liver enzymes were associated with all-cause mortality in each sex and hepatitis virus infection status. In participants without infection, those with more than twice the upper level of normal (ULN), which was defined as 30 IU/L for AST and ALT and 50 IU/L for GGT, had a higher risk of non-liver disease mortality compared to those below the ULN (HR 1.69; 95% confidence interval 1.13-2.53, 1.49; 1.02-2.18, 1.39; 1.11-1.73, 1.72; 1.08-2.74 and 1.72; 1.10-2.69 for AST, ALT, and GGT in men and AST and GGT in women, respectively), except for ALT in women.

CONCLUSIONS

In participants without hepatitis virus infection, serum liver enzyme levels were positively associated with all-cause mortality. Similar associations were also found for non-liver disease mortality.

Reproductive history and risk of cognitive impairment in Japanese women

OBJECTIVE

While exposure to endogenous estrogen may be associated with better cognitive performance, it is still unclear whether it has an association with mild cognitive impairment (MCI) or dementia. The aim of this study was to clarify the effects of reproductive history, as a surrogate marker of exposure to endogenous estrogen, on the risk of cognitive impairment (MCI or dementia) in women.

STUDY DESIGN

A total of 747 women aged 40-59 years in the Saku area (Nagano Prefecture) were followed as part of the Japan Public Health Center-based Prospective (JPHC) Study, which started in 1990. Participants had undergone a mental health examination in 2014-2015.

MAIN OUTCOME MEASURES

We used multiple logistic regression to analyze the association between reproductive history, obtained at baseline and 10-year follow-up, with current cognitive impairment diagnosed by a trained psychiatrist, adjusting for various lifestyle factors.

RESULTS

Among 670 eligible women, current cognitive impairment was diagnosed in 227, 196 of whom had MCI and 31 dementia. A longer reproductive period had a significantly inverse association with cognitive impairment (P-trend = 0.032). In particular, women with a reproductive period ≥38 years compared with ≤33 years had a significantly lower risk of cognitive impairment (multivariable adjusted odds ratio=0.62, 95% confidence interval=0.40-0.96).

CONCLUSIONS

A longer reproductive period was associated with a lower risk of cognitive impairment, which suggests that a longer exposure to endogenous estrogen may have a protective effect against cognitive impairment.

Metagenomic and metabolomic analyses reveal distinct stage-specific phenotypes of the gut microbiota in colorectal cancer

In most cases of sporadic colorectal cancers, tumorigenesis is a multistep process, involving genomic alterations in parallel with morphologic changes. In addition, accumulating evidence suggests that the human gut microbiome is linked to the development of colorectal cancer. Here we performed fecal metagenomic and metabolomic studies on samples from a large cohort of 616 participants who underwent colonoscopy to assess taxonomic and functional characteristics of gut microbiota and metabolites. Microbiome and metabolome shifts were apparent in cases of multiple polypoid adenomas and intramucosal carcinomas, in addition to more advanced lesions. We found two distinct patterns of microbiome elevations. First, the relative abundance of Fusobacterium nucleatum spp. was significantly (P < 0.005) elevated continuously from intramucosal carcinoma to more advanced stages. Second, Atopobium parvulum and Actinomyces odontolyticus, which co-occurred in intramucosal carcinomas, were significantly (P < 0.005) increased only in multiple polypoid adenomas and/or intramucosal carcinomas. Metabolome analyses showed that branched-chain amino acids and phenylalanine were significantly (P < 0.005) increased in intramucosal carcinomas and bile acids, including deoxycholate, were significantly (P < 0.005) elevated in multiple polypoid adenomas and/or intramucosal carcinomas. We identified metagenomic and metabolomic markers to discriminate cases of intramucosal carcinoma from the healthy controls. Our large-cohort multi-omics data indicate that shifts in the microbiome and metabolome occur from the very early stages of the development of colorectal cancer, which is of possible etiological and diagnostic importance.

Coffee consumption and mortality in Japanese men and women: A pooled analysis of eight population-based cohort studies in Japan (Japan Cohort Consortium)

Coffee consumption is increasing globally. We aimed to assess the effect of coffee consumption on the risk of all-cause and cause-specific mortality in a pooled analysis of eight population-based cohort studies in Japan (Japan Cohort Consortium). Data came from eight Japanese cohort studies (144,750 men and 168,631 women). During a mean follow-up time of 17 years, 52,943 deaths occurred. More specifically, 19,495 cancer deaths, 7321 deaths due to heart disease, 6387 cerebrovascular, 3490 respiratory disease and 3382 injuries and accidents. A random effects model was applied to obtain pooled hazard ratios (HRs) and 95% confidence intervals (95%CIs). In both sexes, coffee consumption up to 5 cups/day was overall protective in relation to all-cause mortality, with the association attenuating in the highest category of coffee consumption (≥5 cups/day). In men, a similar inverse association was observed for major causes of mortality except cancer. In women, coffee consumption decreased the risk for mortality due to heart disease in the 1-2 cups/day category, but increased the risk in the ≥5 cups/day category. Coffee consumption was not associated with cancer in both sexes. Results were similar among male current smokers and female never-smokers. Based on available data, this pooled analysis suggests that coffee consumption under five cups per day may be beneficial for reducing the risk of mortality due to major causes.

Association Between Okinawan Vegetables Consumption and Risk of Type 2 Diabetes in Japanese Communities: The JPHC Study

Background

Some Okinawan vegetables have been reported to have anti-diabetic activity; however, no prospective cohort study has clarified whether consumption of Okinawan vegetables is associated with a risk of type 2 diabetes. This study aimed to determine the association between consumption of Okinawan vegetables and risk of type 2 diabetes through a large-scale, population-based, prospective study in Japan.

Methods

We examined 10,732 participants (4,714 men and 6,018 women) aged 45–74 years who resided in Okinawa. Participants were asked to answer a 147-item food frequency questionnaire. We calculated the overall amount of Okinawan vegetables consumed and the amount of seven specific kinds of Okinawan vegetables consumed. The odds ratios (ORs) for self-reported type 2 diabetes during 5 years of follow-up were estimated via multivariate logistic regression analysis.

Results

During the 5-year period, 216 new cases (123 men and 93 women) of type 2 diabetes were reported. Comparing the highest tertile to the lowest tertile of intake, the overall amount of Okinawan vegetables consumed was not associated with risk of type 2 diabetes in men (OR 1.22; 95% confidence interval [CI], 0.74–2.01, P-trend = 0.53) or in women (OR 0.96; 95% CI, 0.57–1.62, P-trend = 0.89). The consumption of seven specific kinds of Okinawan vegetables was also not associated with the risk of type 2 diabetes.

Conclusions

The consumption of total Okinawan vegetables was not associated with the risk of type 2 diabetes.

Diet quality and depression risk in a Japanese population: the Japan Public Health Center (JPHC)-based Prospective Study

The association of overall diet quality based on the Japanese Food Guide Spinning Top with risk of depression is not known. This prospective cohort study aimed to determine whether higher adherence to the Japanese food guide reduced the risk of depression. Of 12,219 residents enrolled at baseline, we extracted 1,112 participants who completed a 5-year follow-up (1995) and participated in a mental health screening (2014–2015). Diet quality was scored based on adherence to the Japanese food guide and the ratio of white to red meat according to the Alternative Healthy Index and ranged from 0 (worst) to 80 (best). We calculated odds ratios and 95% confidence intervals for current psychiatrist-diagnosed depression per quartile of total score and of eight component scores with the lowest quartile as reference. Mean age of the participants was 73 years and 59% were women. Total diet quality score was not significantly associated with risk of depression 20 years after the baseline assessment. Among the eight components on the diet quality score, there was a significantly reduced risk for the highest quartile of the white to red meat ratio score. In conclusion, our results do not indicate that higher adherence to the Japanese food guide prevents depression.

Smoking, Alcohol Consumption, and Risks for Biliary Tract Cancer and Intrahepatic Bile Duct Cancer

BACKGROUND

Smoking and alcohol are established risk factors for several types of cancer, but the effects on biliary cancers, comprising biliary tract cancer (BTC) and intrahepatic bile duct cancer (IHBDC), have been inconclusive.

METHODS

In this population-based prospective cohort study in Japan, we investigated the association of smoking and alcohol consumption with the risks of BTC and its subtypes and IHBDC incidence in men and women. Furthermore, the association of smoking stratified by drinking status was investigated. The hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using the Cox proportional hazard model.

RESULTS

A total of 48,367 men and 54,776 women aged 40-69 years were enrolled from 1990 through 1994 and followed up for 846,417 person-years in men and 1,021,330 person-years in women until 2012, during which 246 BTC and 80 IHBDC male cases and 227 BTC and 60 IHBDC female cases were identified. In men, smoking was significantly associated with an increased risk of IHBDC (HR 2.25; 95% CI, 1.19-4.25 for current smokers with ≥30 pack-years compared with non-smokers), and the risk was enhanced among regular drinkers compared with non/occasional-drinkers (HR 3.48; 95% CI, 1.41-8.61). A non-significant increase of IHBDC risk associated with alcohol was observed. Neither smoking nor alcohol consumption was associated with BTC risk. In women, the association of smoking and alcohol consumption with IHBDC and BTC was unclear because current smokers and regular drinkers were very few.

CONCLUSION

Our findings suggest that smoking increases IHBDC risk in men, especially among regular drinkers.

Diabetes and cancer risk: A Mendelian randomization study

Earlier cohort studies using conventional regression models have consistently shown an increased cancer risk among individuals with type 2 diabetes. However, reverse causality and residual confounding due to common risk factors could exist, and it remains unclear whether diabetes per se contributes to cancer development. Mendelian randomization analyses might clarify the true association between diabetes and cancer risk. We conducted a case-cohort study with 10,536 subcohort subjects and 3,541 newly diagnosed cancer cases derived from 32,949 eligible participants aged 40-69 years within the Japan Public Health Center-based Prospective Study. With 29 known type 2 diabetes susceptibility variants, we used an inverse variance-weighted method to estimate hazard ratios for the associations of diabetes with risks of total and site-specific cancers. The hazard ratios of cancer per doubling of the probability of diabetes were 1.03 (95% confidence interval [CI], 0.92-1.15) overall, 1.08 (95% CI: 0.73-1.59) for the pancreas, 0.80 (95% CI: 0.57-1.14) for the liver and 0.90 (95% CI: 0.74-1.10) for the colorectum. Additional analyses, using publicly available large-scale genome-wide association study data on colorectal cancer in Japan, resulted in a narrower CI (hazard ratio: 1.00; 95% CI: 0.93-1.07). In this prospective Mendelian randomization study with a large number of incident cancer cases, we found no strong evidence to support associations between diabetes and overall and site-specific cancer risks. Our findings suggest that there is little evidence to support the genetic role of type 2 diabetes in cancer development in the Japanese population.

The Nutritional Characteristics of the Hypotensive WASHOKU-modified DASH Diet: A Sub-analysis of the DASH-JUMP Study

Background

We developed a WASHOKU-modified DASH diet named DASH-JUMP. We previously reported the hypotensive effect of the DASH-JUMP diet in Japanese participants with untreated high-normal Blood Pressure (BP) or stage 1 hypertension.

Objective

We aim to introduce the DASH-JUMP diet worldwide as a new lifestyle medicine. Accordingly, we prospectively assessed the nutritional characteristics of the DASH-JUMP diet.

Methods

Participants were treated with the DASH-JUMP diet for 2 months. Then, for 4 months after the intervention, they consumed their usual diets. We conducted a nutritional survey using the FFQg nutrient questionnaire at baseline and after 1, 2, 3, and 6 months. We received completed questionnaires from 55 participants (28 men and 27 women; mean age 54.2 ± 8.0 years) and analyzed them.

Results

The DASH-JUMP diet is rich in green-yellow vegetables, seaweed, milk, and mushrooms, while it has low contents of meat, eggs, confectionery, oils and fats, pickles, shellfish boiled in sweetened soy sauce, and fruits. Nutrients significantly associated with the observed change in systolic BP were niacin (P = 0.005) and carbohydrate (P = 0.033). The results of the FFQg questionnaire revealed that participants who had an increased BP at 1 month after ceasing the intervention had eating habits that broadly imitated the DASH-JUMP diet at 4 months after ceasing the intervention. Therefore, the systolic and diastolic BP values at 4 months after ceasing the intervention decreased significantly compared to those at baseline.

Conclusion

The DASH-JUMP diet may represent a new lifestyle medicine for reducing hypertension.

Helicobacter pylori infection, atrophic gastritis, and risk of pancreatic cancer: A population-based cohort study in a large Japanese population: the JPHC Study

Helicobacter pylori (H. pylori), an established risk factor for gastric cancer, is suggested to also play a role in the development of pancreatic cancer; however, the association remains inconclusive. We examined this association among Japanese men and women. H. pylori and atrophic gastritis (AG) status were determined serologically, using blood sample collected during health checkups. A total of 20,116 subjects enrolled in the Japan Public Health Center-based Prospective Study Cohort II with available data on H. pylori seropositivity (anti-H. pylori) and AG were followed until the end of 2010. Cox proportional hazards models were used to calculate the hazard ratios (HR) and 95% confidence intervals (CI), using the information from the baseline survey. During 320,470 person-years of follow-up, 119 cases of pancreatic cancer were identified. No statically significant increase or decrease in pancreatic cancer risk was observed for H. pylori and AG status, independently or in combination. In a multivariable-adjusted model, we observed a non-significant decrease in the risk among those who had AG but were anti-H. pylori seronegative (HR 0.57, 95% CI 0.31–1.03). In a stratified analysis, we observed a statistically significant increased risk of pancreatic cancer for AG+ (HR 3.64, 95% CI 1.37–9.66), and AG+/anti-H. pylori− or AG+/anti-H. pylori+ (HR 5.21, 95% CI 1.14–23.87) among current smokers. Non-smokers in all categories of AG and anti-H. pylori showed a non-statistical decrease in the risk. There was no statistically significant interaction between H. pylori infection, AG status, and smoking status. Our findings suggest H. pylori seropositivity and AG, individually or in combination, are not associated with the risk of pancreatic cancer in a general Japanese population. Among current smokers, pancreatic cancer risk increased with AG, regardless of H. pylori infection status.

Novel Risk Loci Identified in a Genome-Wide Association Study of Urolithiasis in a Japanese Population

BACKGROUND

A family history of urolithiasis is associated with a more than doubling of urolithiasis risk, and a twin study estimating 56% heritability of the condition suggests a pivotal role for host genetic factors. However, previous genome-wide association studies (GWAS) have identified only six risk-related loci.

METHODS

To identify novel urolithiasis-related loci in the Japanese population, we performed a large-scale GWAS of 11,130 cases and 187,639 controls, followed by a replication analysis of 2289 cases and 3817 controls. Diagnosis of urolithiasis was confirmed either by a clinician or using medical records or self-report. We also assessed the association of urolithiasis loci with 16 quantitative traits, including metabolic, kidney-related, and electrolyte traits (such as body mass index, lipid storage, eGFR, serum uric acid, and serum calcium), using up to 160,000 samples from BioBank Japan.

RESULTS

The analysis identified 14 significant loci, including nine novel loci. Ten regions showed a significant association with at least one quantitative trait, including metabolic, kidney-related, and electrolyte traits, suggesting a common genetic basis for urolithiasis and these quantitative traits. Four novel loci were related to metabolic traits, obesity, hypertriglyceridemia, or hyperuricemia. The remaining ten loci were associated with kidney- or electrolyte-related traits; these may affect crystallization. Weighted genetic risk score analysis indicated that the highest risk group (top 20%) showed an odds ratio of 1.71 (95% confidence interval, 1.42 to 2.06) - 2.13 (95% confidence interval, 2.00 to 2.27) compared with the reference group (bottom 20%).

CONCLUSIONS

Our findings provide evidence that host genetic factors related to regulation of metabolic and crystallization pathways contribute to the development of urolithiasis.