Baseline survey of JPHC study--design and participation rate. Japan Public Health Center-based Prospective Study on Cancer and Cardiovascular Diseases

Reproductive factors and risk of epithelial ovarian cancer: results from the Asia Cohort Consortium

BACKGROUND

There are scarce data on risk factors for epithelial ovarian cancer (EOC) in Asian populations. Our goal was to advance knowledge on reproductive -related risk factors for EOC in a large population of Asian women.

METHODS

This study used pooled individual data from baseline questionnaires in 11 prospective cohorts (baseline years, 1958-2015) in the Asia Cohort Consortium. A Cox proportional hazards regression model was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) adjusting for age, parity and cohort.

RESULTS

After a mean = 17.0 years (SD = 6.3) of follow-up, 674 incident invasive EOC cases were identified among 325,626 women. In multivariable adjusted models we observed an inverse association with parity (5+ children vs. 0, HR = 0.44, 95% CI = 0.28-0.68, Ptrend < 0.001), and a positive association with increasing menopausal age (55+ years vs. <45, HR = 1.77, 95% CI = 1.05-3.01, Ptrend = 0.02) for risk of all EOC.

CONCLUSIONS

In this large study of Asian women we identified an inverse association with parity and a positive association with higher menopausal age in relation to EOC risk. Further work is needed to understand EOC risk factors for rare histologic subtypes that occur more frequently in Asian populations.

Association between physical multimorbidity in middle adulthood and mortality: findings from two large cohort studies in Japan

BACKGROUND

While previous literature suggests that multimorbidity is linked to a higher risk of mortality, evidence is scarce among individuals in middle adulthood. We aimed to examine the association between physical multimorbidity and all-cause mortality among individuals aged 40-64 years at baseline in Japan.

METHODS

Data were obtained from two cohort studies, the Japan Public Health Center-based Prospective Study (JPHC) and the Japan Epidemiology Collaboration on Occupational Health Study (J-ECOH). The study participants were 144,774 individuals aged 40-64 years at baseline who were followed up for a maximum of 29 and 10 years in the JPHC and J-ECOH, respectively. Multimorbidity was defined as the presence of ≥ 2 of 10 morbidities or conditions based on self-reported information. A Cox proportional hazards model was used to examine the association in relation to all-cause mortality. We calculated pooled hazard ratios (HR) and corresponding 95% confidence intervals (CI) using a random-effects meta-analysis model. Cause-specific analysis was performed using the JPHC dataset, which provided a sufficient number of events for mortality due to physical disorders, mental disorders/suicide, and unintentional injuries.

RESULTS

During a follow-up of 2,304,375 person-years in the JPHC and 311,637 person-years in the J-ECOH, 23,611 and 275 deaths were recorded, respectively. Participants with vs. without physical multimorbidity at baseline were more likely to die prematurely in both cohorts with a pooled HR of 1.61 (95%CI = 1.29-2.01). Cause-specific analyses among the JPHC participants revealed that physical multimorbidity at baseline was linked with mortality due to physical disorders, mortality due to mental disorders/suicide, and mortality due to unintentional injuries.

CONCLUSIONS

Physical multimorbidity in middle adulthood is associated with an increased risk of all-cause mortality in Japan.

Active and passive smoking and breast cancer in Japan: a pooled analysis of nine population-based cohort studies

BACKGROUND

Epidemiological studies have shown inconsistent results regarding the link between smoking and breast cancer risk, despite the biological plausibility of a positive association.

METHODS

Participants were 166 611 women from nine prospective cohort studies in Japan which launched in 1984-1994 and followed for 8-22 years. Information on smoking and secondhand smoke was obtained through self-administered baseline questionnaires. Breast cancer was defined as code C50 according to the International Classification of Diseases for Oncology, 3rd Edition or the International Classification of Diseases, 10th Revision. After adjusting for several potential confounders, relative risks for breast cancer were calculated in the individual studies according to the current or previous status of active and passive smoking using Cox regression, followed by a summary estimate of hazard ratios using random-effects meta-analyses.

RESULTS

Of the 60 441 participants who reported being premenopausal and 106 170 who reported being postmenopausal at baseline, 897 and 1168 developed breast cancer during follow-up, respectively. Compared with never smokers, current smokers had a higher risk of developing breast cancer before the age of 50 years. In addition, ever smokers who started smoking at 30 years of age or younger, or who started smoking before first childbirth, had a higher risk of developing breast cancer before the age of 50 years. No association between adulthood or childhood exposure to secondhand smoke and breast cancer was observed.

CONCLUSION

Smoking may increase the risk of premenopausal breast cancer, and smoking earlier in life might be especially harmful. The impact of secondhand smoke needs further investigation.

Adult Height and Risk of Colorectal Cancer: A Pooled Analysis of 10 Population-based Cohort Studies in Japan

BACKGROUND

While tall stature has been linked to an increase in the risk of colorectal cancer (CRC), its association with cancer in the colorectum and its subsites remains unclear among Asians.

METHODS

We conducted a pooled analysis of 10 population-based cohort studies among adults in Japan. Each study estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC incidence associated with adult height were estimated using Cox proportional hazards regression with adjustment of the same set of covariates were then pooled to estimate summary HRs incidence using random-effect models.

RESULTS

We identified 9,470 CRC incidences among 390,063 participants during 5,672,930 person-years of follow-up. Men and women with tall stature had a higher risk of CRC and colon cancer. HRs for CRC, colon cancer, and distal colon cancer for the highest versus lowest height categories were 1.23 (95% CI, 1.07-1.40), 1.22 (95% CI, 1.09-1.36), and 1.27 (95% CI, 1.08-1.49), respectively, in men and 1.21 (95% CI, 1.09-1.35), 1.23 (95% CI, 1.08-1.40), and 1.35 (95% CI, 1.003-1.81), respectively, in women. The association with proximal colon cancer and rectal cancer was less evident in both sexes.

CONCLUSION

This pooled analysis confirms the link between tall stature and a higher risk of CRC and colon cancer (especially distal colon) among the Japanese and adds evidence to support the use of adult height to identify those at a higher risk of CRC.

Body mass index and esophageal and gastric cancer: A pooled analysis of 10 population-based cohort studies in Japan

The effect of body mass index (BMI) on esophageal and gastric carcinogenesis might be heterogeneous, depending on subtype or subsite. However, findings from prospective evaluations of BMI associated with these cancers among Asian populations have been inconsistent and limited, especially for esophageal adenocarcinoma and gastric cardia cancer. We performed a pooled analysis of 10 population-based cohort studies to examine this association in 394,247 Japanese individuals. We used Cox proportional hazards regression to estimate study-specific hazard ratios (HRs) and 95% confidence intervals (CIs), then pooled these estimates to calculate summary HRs with a random effects model. During 5,750,107 person-years of follow-up, 1569 esophageal cancer (1038 squamous cell carcinoma and 86 adenocarcinoma) and 11,095 gastric (728 cardia and 5620 noncardia) cancer incident cases were identified. An inverse association was observed between BMI and esophageal squamous cell carcinoma (HR per 5-kg/m2 increase 0.57, 95% CI 0.50-0.65), whereas a positive association was seen in gastric cardia cancer (HR 1.15, 95% CI 1.00-1.32). A nonsignificant and significant positive association for overweight or obese (BMI ≥25 kg/m2 ) relative to BMI <25 kg/m2 was observed with esophageal adenocarcinoma (HR 1.32, 95% CI 0.80-2.17) and gastric cardia cancer (HR 1.24, 95% CI 1.05-1.46), respectively. No clear association with BMI was found for gastric noncardia cancer. This prospective study-the largest in an Asian country-provides a comprehensive quantitative estimate of the association of BMI with upper gastrointestinal cancer and confirms the subtype- or subsite-specific carcinogenic impact of BMI in a Japanese population.

Vegetable and fruit intake and colorectal cancer risk by smoking status in adults: The Japan Public Health Center-based Prospective Study

BACKGROUND

Cigarette smoke contains many oxidants and free radicals which may affect the association between vegetable and fruit intake and colorectal cancer (CRC) risk. However, this relationship remains unclear.

OBJECTIVE

This study aimed to investigate the associations between vegetable and fruit intake and CRC risk by smoking status.

METHODS

The Japan Public Health Center-based Prospective Study is a population-based prospective cohort study. Participants completed a self-administered questionnaire in 1995-1999 (baseline survey) and were followed through to 2013. At the baseline survey, 89,283 residents (41,797 men and 47,486 women) aged 45-74 years were included. Participants were asked about their lifestyle and dietary habits. To investigate the association of vegetable and fruit intake with risk of CRC, Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). We analyzed the relationship between vegetable and fruit intake and CRC risk stratified by sex and smoking status.

RESULTS

During follow-up, 2261 participants were diagnosed with CRC. Overall, vegetable and fruit intake were not associated with CRC risk in either sex. When stratified by sex and smoking status, CRC risk among male never smokers was inversely associated with intake of vegetables and fruit combined (HR: 0.72; 95% CI: 0.53, 0.98; highest vs lowest quartile p trend = 0.01) and fruit alone (HR: 0.62; 95% CI: 0.45, 0.86; p trend < 0.01).

CONCLUSIONS

Cigarette smoking may affect the association between vegetable and fruit intake and CRC risk among men.

Soy product intake and risk of incident disabling dementia: the JPHC Disabling Dementia Study

PURPOSE

We evaluated the association between total soy, soy product (natto, miso and tofu) and isoflavone intake and incident disabling dementia in a Japanese population.

METHODS

We conducted a population-based prospective study in 18,991 men and 22,456 women. Intake of soy products and isoflavone was calculated using a validated food frequency questionnaire when participants were 45-74 years old (1995 and 1998). Incident disabling dementia was defined by the daily living disability status related to dementia in the long-term care insurance program of Japan from 2006 to 2016. Multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) of disabling dementia were calculated by quintiles of total soy, individual soy product and isoflavone intake, using Cox proportional hazard regression models.

RESULTS

Total soy product intake was not associated with disabling dementia risk in both men and women. By individual soy products, natto intake was marginally inversely associated with disabling dementia in women (trend P = 0.050). When we stratified by age, this inverse association was clearer in women aged under 60 years (multivariate HR for the highest versus lowest quintile was 0.78, 95% CI 0.59-1.04, trend P = 0.020 for those aged under 60 years and 0.90, 95% CI 0.77-1.05, trend P = 0.23 for those aged 60 years and older, respectively). Any soy product or isoflavone intake was not associated with disabling dementia risk in men.

CONCLUSIONS

Although total soy product intake was not associated with disabling dementia risk, natto intake may contribute to reducing the risk of disabling dementia in women, especially in those aged under 60 years.

A Predictive Model of Noncardia Gastric Adenocarcinoma Risk Using Antibody Response to Helicobacter pylori Proteins and Pepsinogen

BACKGROUND

Blood-based biomarkers for gastric cancer risk stratification could facilitate targeting screening to people who will benefit from it most. The ABC Method, which stratifies individuals by their Helicobacter pylori infection and serum-diagnosed chronic atrophic gastritis status, is currently used in Japan for this purpose. Most gastric cancers are caused by chronic H. pylori infection, but few studies have explored the capability of antibody response to H. pylori proteins to predict gastric cancer risk in addition to established predictors.

METHODS

We used the least absolute shrinkage and selection operator (Lasso) to build a predictive model of noncardia gastric adenocarcinoma risk from serum data on pepsinogen and antibody response to 13 H. pylori antigens as well as demographic and lifestyle factors from a large international study in East Asia.

RESULTS

Our best model had a significantly (P < 0.001) higher AUC of 73.79% [95% confidence interval (CI), 70.86%-76.73%] than the ABC Method (68.75%; 95% CI, 65.91%-71.58%). At 75% specificity, the new model had greater sensitivity than the ABC Method (58.67% vs. 52.68%) as well as NPV (68.24% vs. 66.29%).

CONCLUSIONS

Along with serologically defined chronic atrophic gastritis, antibody response to the H. pylori proteins HP 0305, HP 1564, and UreA can improve the prediction of gastric cancer risk.

IMPACT

The new risk stratification model could help target more invasive gastric screening resources to individuals at high risk.

Cross-sectional associations between the types/amounts of beverages consumed and the glycemia status: The Japan public health center-based Prospective Diabetes study

Background

The associations between the types/amounts of beverages consumed in daily life and measures of the glycemia status were investigated in a Japanese population-based cohort.

Methods

Data from the baseline survey of the Japan Public Health Center-based Prospective Diabetes cohort were used. A cross-sectional analysis was performed in 3852 men and 6003 women who were evaluated under the fasting condition. The daily consumptions of coffee, green tea, oolong tea, black tea, soft drinks, fruit juices, or plain water were assessed using a self-reported questionnaire. Multivariable-adjusted linear regression analyses were performed using measures of the glycemia status (fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c) ) as dependent variables and the types/amounts of beverages consumed as the independent variables, to calculate the differences according to the types/amounts of beverages consumed.

Results

In the multivariable-adjusted models, coffee consumption of ≥240 mL/day was significantly associated with a change of the FPG level by −1.9 mg/dL in men (p = 0.013) and −1.4 mg/dL in women (p = 0.015), as compared to coffee consumption of 0 mL/day. No significant association of the FPG level was observed with any of the other types/amounts of beverages consumed. On the other hand, significant associations were found between the HbA1c levels and consumption of several types of beverages.

Conclusions

High coffee consumption was associated with lower FPG levels in this Japanese population. Some unexpected associations of the HbA1c levels with the consumption of some types of beverages were observed, which need to be further investigated.

Dietary fibre intake is associated with reduced risk of lung cancer: a Japan public health centre-based prospective study (JPHC)

BACKGROUND

Several epidemiological studies have been conducted to draw consistent conclusions regarding the effect of dietary fibre on lung diseases and lung cancer. However, the effect of dietary fibre on the incidence of lung cancer remains unclear in an Asian population.

METHODS

We investigated the association between the intake of total dietary fibre and dietary fibre from different food sources and lung cancer incidence in a Japan public health centre-based prospective study (JPHC). A total of 73 405 participants (33 012 men and 40 393 women) aged 45-74 years were eligible for our study. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During a median follow-up of 18.0 years, 1546 (1042 men and 504 women) newly diagnosed cases of lung cancer were ascertained. In the multivariable models, total dietary fibre intake was inversely associated with lung cancer risk in men, the HRs Q5 vs Q1 (95% CI) were 0.77 (0.62 to 0.94), P-trend = 0.020. Dietary fibre intake from vegetables was protectively associated with lung cancer risk in men [HR Q5 vs Q1 (95% CI): 0.80 (0.64 to 0.99), P-trend = 0.053]. However, no such association was observed in women.

CONCLUSIONS

In men, a high intake of total dietary fibre may have preventive benefits for lung cancer incidence: dietary fibre intake from vegetables was associated with a lower incidence of lung cancer. However, similar associations did not appear in women. Further investigations are required to confirm the association between dietary fibre and lung cancer risk in women.

Peanut Consumption and Risk of Stroke and Ischemic Heart Disease in Japanese Men and Women: The JPHC Study

[Figure: see text].

Association of risk factors with type 2 diabetes: A systematic review

Diabetes is the leading cause of severe health complications and one of the top 10 causes of death worldwide. To date, diabetes has no cure, and therefore, it is necessary to take precautionary measures to avoid its occurrence. The main aim of this systematic review is to identify the majority of the risk factors for the incidence/prevalence of type 2 diabetes mellitus on one hand, and to give a critical analysis of the cohort/cross-sectional studies which examine the impact of the association of risk factors on diabetes. Consequently, we provide insights on risk factors whose interactions are major players in developing diabetes. We conclude with recommendations to allied health professionals, individuals and government institutions to support better diagnosis and prognosis of the disease.

Acrylamide-Hemoglobin Adduct Levels in a Japanese Population and Comparison with Acrylamide Exposure Assessed by the Duplicated Method or a Food Frequency Questionnaire

The levels of hemoglobin adducts of acrylamide (AA-Hb), a biomarker of acrylamide exposure, have not been reported for Japanese subjects. Herein, we determined the AA-Hb levels in a Japanese population and compared them with the estimated dietary intake from the duplicate diet method (DM) and a food frequency questionnaire (FFQ). One-day DM samples, FFQ, and blood samples were collected from 89 participants and analyzed for acrylamide. AA-Hb was analyzed using liquid chromatography tandem mass spectrometry and the N-alkyl Edman method. Participants were divided into tertiles of estimated acrylamide intake and geometric means (GMs) of AA-Hb adjusted for sex and smoking status. A stratified analysis according to smoking status was also performed. The average AA-Hb levels for all participants, never, past, and current smokers were 46, 38, 65, and 86 pmol/g Hb, respectively. GMs of AA-Hb levels in all participants were significantly associated with tertiles of estimated acrylamide intake from DM (p for trend = 0.02) and FFQ (p for trend = 0.04), although no association with smokers was observed. AA-Hb levels reflected smoking status, which were similar to values reported in Western populations, and they were associated with estimated dietary intake of acrylamide when adjusted for sex and smoking status.

The effect of exposure to long working hours on stroke: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing joint estimates of the work-related burden of disease and injury (WHO/ILO Joint Estimates), with contributions from a large network of individual experts. Evidence from mechanistic data and prior studies suggests that exposure to long working hours may cause stroke. In this paper, we present a systematic review and meta-analysis of parameters for estimating the number of deaths and disability-adjusted life years from stroke that are attributable to exposure to long working hours, for the development of the WHO/ILO Joint Estimates.

OBJECTIVES

We aimed to systematically review and meta-analyse estimates of the effect of exposure to long working hours (three categories: 41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on stroke (three outcomes: prevalence, incidence, and mortality).

DATA SOURCES

A protocol was developed and published, applying the Navigation Guide to systematic reviews as an organizing framework where feasible. We searched electronic databases for potentially relevant records from published and unpublished studies, including Ovid MEDLINE, PubMed, EMBASE, Scopus, Web of Science, CISDOC, PsycINFO, and WHO ICTRP. We also searched grey literature databases, Internet search engines, and organizational websites; hand-searched reference lists of previous systematic reviews; and consulted additional experts.

STUDY ELIGIBILITY AND CRITERIA

We included working-age (≥15 years) individuals in the formal and informal economy in any WHO and/or ILO Member State but excluded children (aged < 15 years) and unpaid domestic workers. We included randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the effect of exposure to long working hours (41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on stroke (prevalence, incidence or mortality).

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors independently screened titles and abstracts against the eligibility criteria at a first review stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. Missing data were requested from principal study authors. We combined relative risks using random-effects meta-analysis. Two or more review authors assessed the risk of bias, quality of evidence and strength of evidence, using the Navigation Guide and GRADE tools and approaches adapted to this project.

RESULTS

Twenty-two studies (20 cohort studies, 2 case-control studies) met the inclusion criteria, comprising a total of 839,680 participants (364,616 females) in eight countries from three WHO regions (Americas, Europe, and Western Pacific). The exposure was measured using self-reports in all studies, and the outcome was assessed with administrative health records (13 studies), self-reported physician diagnosis (7 studies), direct diagnosis by a physician (1 study) or during a medical interview (1 study). The outcome was defined as an incident non-fatal stroke event in nine studies (7 cohort studies, 2 case-control studies), incident fatal stroke event in one cohort study and incident non-fatal or fatal ("mixed") event in 12 studies (all cohort studies). Cohort studies were judged to have a relatively low risk of bias; therefore, we prioritized evidence from these studies, but synthesised evidence from case-control studies as supporting evidence. For the bodies of evidence for both outcomes with any eligible studies (i.e. stroke incidence and mortality), we did not have serious concerns for risk of bias (at least for the cohort studies). Eligible studies were found on the effects of long working hours on stroke incidence and mortality, but not prevalence. Compared with working 35-40 h/week, we were uncertain about the effect on incidence of stroke due to working 41-48 h/week (relative risk (RR) 1.04, 95% confidence interval (CI) 0.94-1.14, 18 studies, 277,202 participants, I² 0%, low quality of evidence). There may have been an increased risk for acquiring stroke when working 49-54 h/week compared with 35-40 h/week (RR 1.13, 95% CI 1.00-1.28, 17 studies, 275,181participants, I² 0%, p 0.04, moderate quality of evidence). Compared with working 35-40 h/week, working ≥55 h/week may have led to a moderate, clinically meaningful increase in the risk of acquiring stroke, when followed up between one year and 20 years (RR 1.35, 95% CI 1.13 to 1.61, 7 studies, 162,644 participants, I² 3%, moderate quality of evidence). Compared with working 35-40 h/week, we were very uncertain about the effect on dying (mortality) of stroke due to working 41-48 h/week (RR 1.01, 95% CI 0.91-1.12, 12 studies, 265,937 participants, I² 0%, low quality of evidence), 49-54 h/week (RR 1.13, 95% CI 0.99-1.29, 11 studies, 256,129 participants, I² 0%, low quality of evidence) and 55 h/week (RR 1.08, 95% CI 0.89-1.31, 10 studies, 664,647 participants, I² 20%, low quality of evidence). Subgroup analyses found no evidence for differences by WHO region, age, sex, socioeconomic status and type of stroke. Sensitivity analyses found no differences by outcome definition (exclusively non-fatal or fatal versus "mixed") except for the comparison working ≥55 h/week versus 35-40 h/week for stroke incidence (p for subgroup differences: 0.05), risk of bias ("high"/"probably high" ratings in any domain versus "low"/"probably low" in all domains), effect estimate measures (risk versus hazard versus odds ratios) and comparator (exact versus approximate definition).

CONCLUSIONS

We judged the existing bodies of evidence for human evidence as "inadequate evidence for harmfulness" for all exposure categories for stroke prevalence and mortality and for exposure to 41-48 h/week for stroke incidence. Evidence on exposure to 48-54 h/week and ≥55 h/week was judged as "limited evidence for harmfulness" and "sufficient evidence for harmfulness" for stroke incidence, respectively. Producing estimates for the burden of stroke attributable to exposures to working 48-54 and ≥55 h/week appears evidence-based, and the pooled effect estimates presented in this systematic review could be used as input data for the WHO/ILO Joint Estimates. PROTOCOL IDENTIFIER: https://doi.org/10.1016/j.envint.2018.06.016.

PROSPERO REGISTRATION NUMBER

CRD42017060124.

Smoking and colorectal cancer: A pooled analysis of 10 population-based cohort studies in Japan

Smoking has been consistently associated with the risk of colorectal cancer (CRC) in Western populations; however, evidence is limited and inconsistent in Asian people. To assess the association of smoking status, smoking intensity and smoking cessation with colorectal risk in the Japanese population, we performed a pooled analysis of 10 population-based cohort studies. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox's proportional hazards model and then pooled using a random-effects model. Among 363 409 participants followed up for 2 666 004 person-years, 9232 incident CRCs were identified. In men, compared with never smokers, ever smokers showed higher risk of CRC. The HRs (95% CI) were 1.19 (1.10-1.29) for CRC, 1.19 (1.09-1.30) for colon cancer, 1.28 (1.13-1.46) for distal colon cancer and 1.21 (1.07-1.36) for rectal cancer. Smoking was associated with risk of CRC in a dose-response manner. In women, compared with never smokers, ever smokers showed increased risk of distal colon cancer (1.47 [1.19-1.82]). There was no evidence of a significant gender difference in the association of smoking and CRC risk. Our results confirm that smoking is associated with an increased risk of CRC, both overall and subsites, in Japanese men and distal colon cancer in Japanese women.

Dietary Acrylamide Intake and Risk of Lung Cancer: The Japan Public Health Center Based Prospective Study

Acrylamide, which forms in heat-treated foods with high carbohydrate content, is a probable human carcinogen. This study aimed to evaluate the association between dietary acrylamide intake and lung cancer using data from the Japan Public Health Center based Prospective Study. Our study included 85,303 participants who completed a food frequency questionnaire. Cox proportional hazards regression models were used to assess hazard ratios and 95% confidence intervals (CIs) after adjusting for confounders. After 14.3 years and 15.4 years of mean follow-up period, 1187 and 485 lung cancer cases were identified in men and women, respectively. The multivariable-adjusted hazard ratios of 10-µg/day increment in acrylamide intake were 1.01 (95% CI, 0.99–1.02) in men and 0.98 (95% CI, 0.95–1.02) in women. Compared with the lowest quartile of acrylamide intake, the hazard ratios for the highest quartile were 1.13 (95% CI, 0.95–1.33; p for trend = 0.12) in men and 1.03 (95% CI, 0.78–1.36; p for trend = 0.86) in women in the multivariable-adjusted model. Moreover, there was also no significant association observed in the stratified analysis for histological subtypes of lung cancer. This study demonstrated that dietary acrylamide intake was not associated with increased lung cancer risk in the Japanese population.

Claudin-2 deficiency associates with hypercalciuria in mice and human kidney stone disease

The major risk factor for kidney stone disease is idiopathic hypercalciuria. Recent evidence implicates a role for defective calcium reabsorption in the renal proximal tubule. We hypothesized that claudin-2, a paracellular cation channel protein, mediates proximal tubule calcium reabsorption. We found that claudin-2-null mice have hypercalciuria due to a primary defect in renal tubule calcium transport and papillary nephrocalcinosis that resembles the intratubular plugs in kidney stone formers. Our findings suggest that a proximal tubule defect in calcium reabsorption predisposes to papillary calcification, providing support for the vas washdown hypothesis. Claudin-2-null mice were also found to have increased net intestinal calcium absorption, but reduced paracellular calcium permeability in the colon, suggesting that this was due to reduced intestinal calcium secretion. Common genetic variants in the claudin-2 gene were associated with decreased tissue expression of claudin-2 and increased risk of kidney stones in 2 large population-based studies. Finally, we describe a family in which males with a rare missense variant in claudin-2 have marked hypercalciuria and kidney stone disease. Our findings indicate that claudin-2 is a key regulator of calcium excretion and a potential target for therapies to prevent kidney stones.

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.

Prediagnostic circulating inflammation biomarkers and esophageal squamous cell carcinoma: A case-cohort study in Japan

Esophageal squamous cell carcinoma (ESCC) is the predominant histologic subtype of esophageal cancer worldwide. Measurements of circulating inflammation-related biomarkers may inform etiology or provide noninvasive signatures for early diagnosis. We therefore examined levels of inflammation molecules for associations with ESCC risk. Using a case-cohort study designed within the Japan Public Health Center-based Prospective Study, we measured baseline plasma levels of 92 biomarkers using a multiplex assay in a subcohort of 410 randomly selected participants and 66 participants with incident ESCC (including four cases that occurred in the subcohort). ESCC hazard ratios (HRs) were calculated for 2-4 quantiles of each biomarker by Cox proportional hazards regression models with age as the time metric, adjusted for sex, smoking and alcohol use. Twenty analytes were undetectable in nearly all samples. Of the remaining 72, 12 biomarkers (FGF19, ST1A1, STAMBP, AXIN1, CASP8, NT3, CD6, CDCP1, CD5, SLAMF1, OPG and CSF1) were associated with increased ESCC risk (p_trend  < 0.05) with HRs per quantile 1.28-1.65. Seven biomarkers (CXCL6, CCL23, CXCL5, TGFA, CXCL1, OSM and CCL4) were inversely associated with HRs 0.57-0.72. FGF19, CASP8, STAMBP, ST1A1 and CCL-4 met statistical significance with false discovery rate correction. Associations did not differ <5 vs. ≥5 years between blood collection and ESCC diagnosis. CASP8, STAMBP and ST1A1 were strongly correlated (p < 0.05). Our study expands the range of inflammation molecules associated with the development of this highly lethal neoplasia. Correlations among these novel biomarkers suggest a possible shared pathway. These findings need replication and could further delineate ESCCs molecular mechanisms of carcinogenesis.

Genetic variants of calcium and vitamin D metabolism in kidney stone disease

Kidney stone disease (nephrolithiasis) is a major clinical and economic health burden with a heritability of ~45–60%. We present genome-wide association studies in British and Japanese populations and a trans-ethnic meta-analysis that include 12,123 cases and 417,378 controls, and identify 20 nephrolithiasis-associated loci, seven of which are previously unreported. A CYP24A1 locus is predicted to affect vitamin D metabolism and five loci, DGKD, DGKH, WDR72, GPIC1, and BCR, are predicted to influence calcium-sensing receptor (CaSR) signaling. In a validation cohort of only nephrolithiasis patients, the CYP24A1-associated locus correlates with serum calcium concentration and a number of nephrolithiasis episodes while the DGKD-associated locus correlates with urinary calcium excretion. In vitro, DGKD knockdown impairs CaSR-signal transduction, an effect rectified with the calcimimetic cinacalcet. Our findings indicate that studies of genotype-guided precision-medicine approaches, including withholding vitamin D supplementation and targeting vitamin D activation or CaSR-signaling pathways in patients with recurrent kidney stones, are warranted.

Kidney stones form in the presence of overabundance of crystal-forming substances such as Ca²⁺ and oxalate. Here, the authors report genome-wide association analyses for kidney stone disease, report seven previously unknown loci and find that some of these loci also associate with Ca²⁺ concentration and excretion.

Meat subtypes and colorectal cancer risk: A pooled analysis of 6 cohort studies in Japan

Red meat and processed meat have been suggested to increase risk of colorectal cancer (CRC), especially colon cancer. However, it remains unclear whether these associations differ according to meat subtypes or colon subsites. The present study addressed this issue by undertaking a pooled analysis of large population-based cohort studies in Japan: 5 studies comprising 232 403 participants (5694 CRC cases) for analysis based on frequency of meat intake, and 2 studies comprising 123 635 participants (3550 CRC cases) for analysis based on intake quantity. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using the Cox proportional hazards model and then pooled using the random effect model. Comparing the highest vs lowest quartile, beef intake was associated with an increased risk of colon cancer in women (pooled HR 1.20; 95% CI, 1.01-1.44) and distal colon cancer (DCC) risk in men (pooled HR 1.30; 95% CI, 1.05-1.61). Frequent intake of pork was associated with an increased risk of distal colon cancer in women (pooled HR 1.44; 95% CI, 1.10-1.87) for "3 times/wk or more" vs "less than 1 time/wk". Frequent intake of processed red meat was associated with an increased risk of colon cancer in women (pooled HR 1.39; 95% CI, 0.97-2.00; P trend = .04) for "almost every day" vs "less than 1 time/wk". No association was observed for chicken consumption. The present findings support that intake of beef, pork (women only), and processed red meat (women only) might be associated with a higher risk of colon (distal colon) cancer in Japanese.

Nutrition intake among the Japanese elderly: an intergenerational comparison based on national health and nutrition survey scores

Context: The average Japanese lifespan became the longest in the world in 1986. What factors give the Japanese this longevity? Washoku, or the traditional Japanese diet, is respected globally for its nutritionally-balanced and healthy eating habits. This uniquely Japanese way of eating may be one factor that helps extend the Japanese lifespan. Objective: To explain the nutrition intake characteristics of today's Japanese elderly compared with their children's generation and to discuss the association between nutrition intake and various diseases and health issues in the general adult population. Methods: This study compared the characteristics of nutrition status and nutrition intake among today's elderly and their children's generation by using National Health and Nutrition Survey scores. Results: Japanese elderly had high adequacy in all nutrients as well as a high intake of potatoes, pulses, vegetables, fruits, algae, and fish and shellfish compared with their children's generation. Conclusion: Nutrition intake among the Japanese elderly had the characteristics of washoku, but these characteristics were not passed on to the next generation. Extension of the average lifespan and improved health could be achieved by modifying nutrition intake, even after reaching the age of onset of lifestyle- and age-related diseases, typically the 50s.

Diet Quality Affects the Association between Census-Based Neighborhood Deprivation and All-Cause Mortality in Japanese Men and Women: The Japan Public Health Center-Based Prospective Study

Background: Individuals residing in more deprived areas with a lower diet quality might have a higher mortality risk. We aimed to examine the association between deprivation within an area and all-cause mortality risk according to diet quality. Methods: We conducted a population-based prospective study on 27,994 men and 33,273 women aged 45–75 years. Neighborhood deprivation was assessed using the Japanese areal deprivation index (ADI). Dietary intakes were assessed using a validated 147-item food frequency questionnaire. Results: Individuals residing in the most deprived area had the lowest dietary scores. During the 16.7-year follow-up, compared to individuals with a high quality diet residing in the least deprived area, individuals with a low quality diet had a higher risk of mortality according to increment of ADI (p trend = 0.03); the multivariate-adjusted hazard ratio (95% confidence interval) was 1.09 (0.999–1.19), 1.17 (1.08–1.27), and 1.19 (1.08–1.32) in those residing in the lowest through the highest third of ADI, respectively. However, individuals with a high quality diet had no significant association between ADI and mortality. Conclusion: A well-balanced diet may prevent early death associated with neighborhood socioeconomic status among those residing in highly deprived areas.

Dietary Acrylamide Intake and Risk of Esophageal, Gastric, and Colorectal Cancer: The Japan Public Health Center-Based Prospective Study

BACKGROUND

Acrylamide has been classified as a probable human carcinogen based chiefly on laboratory evidence. However, the influence of dietary acrylamide intake on risk of esophageal, gastric, and colorectal cancer has not been extensively studied. We aimed to evaluate the association between dietary acrylamide intake and esophageal, gastric, and colorectal cancer using data from the Japan Public Health Center-based Prospective Study.

METHODS

Our study included 87,628 participants who completed a food-frequency questionnaire at enrollment in 1990 and 1993. We used Cox proportional hazards regression models to estimate hazards ratios and 95% confidence intervals (CI) after adjusting for confounding factors.

RESULTS

After 15.5, 15.3, and 15.3 mean years of follow-up for esophageal, gastric, and colorectal cancer, we identified and analyzed 391 esophageal, 2,218 gastric, and 2,470 colorectal cancer cases, respectively. Compared with the lowest quintile of acrylamide intake, the multivariate HR for the highest quintile was 0.86 (95% CI, 0.53-1.39; P _trend = 0.814), 0.84 (95% CI, 0.69-1.01; P _trend = 0.301), and 0.93 (95% CI, 0.79-1.08; P _trend = 0.165) for esophageal, gastric, and colorectal cancer, respectively, in the multivariable-adjusted model. Furthermore, no significant associations were observed when the participants were stratified by cancer subsites.

CONCLUSIONS

In conclusion, this study demonstrated that dietary acrylamide intake was not associated with increased risk of esophageal, gastric, or colorectal cancer among the Japanese population.

IMPACT

It is the first time to assess the effect of dietary acrylamide intake on risk of digestive system cancer in Asian populations.

Smoking and Pancreatic Cancer Incidence: A Pooled Analysis of 10 Population-Based Cohort Studies in Japan

BACKGROUND

Detailed prospective evaluation of cigarette smoking associated with pancreatic cancer risk in large Asian populations is limited. The aim of this study was to examine this association in a Japanese population, with a particular focus on evaluating sex differences.

METHODS

We performed a pooled analysis of 10 population-based cohort studies. We calculated study-specific HRs and 95% confidence intervals (CI) using Cox proportional hazards regression, and then estimated summary HRs by pooling these estimates with a random effects model.

RESULTS

During 4,695,593 person-years of follow-up in 354,154 participants, 1,779 incident pancreatic cancer cases were identified. We observed an increased pancreatic cancer risk for current smoking compared with never smoking in both males [HR (95% CI), 1.59 (1.32-1.91)] and females [HR (95% CI), 1.81 (1.43-2.30)]. Significant risk elevations for former smoking and small cumulative dose of ≤20 pack-years (PY) were observed only among females, regardless of environmental tobacco smoke exposure. Trend analysis indicated significant 6% and nonsignificant 6% increases in pancreatic cancer risk for every 10 PYs in males and females, respectively. Risk became comparable with never smokers after 5 years of smoking cessation in males. In females, however, we observed no risk attenuation by smoking cessation.

CONCLUSIONS

This study supports the well-known association between smoking and pancreatic cancer and indicates potential sex differences in a Japanese population. Quitting smoking would be beneficial for pancreatic cancer prevention, especially in males.

IMPACT

Pancreatic cancer risk is increased with cumulative smoking exposure and decreased with smoking cessation, with potential sex differences.

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.

Working Hours and Risk of Acute Myocardial Infarction and Stroke Among Middle-Aged Japanese Men - The Japan Public Health Center-Based Prospective Study Cohort II

BACKGROUND

Evidence from prospective cohort studies regarding the relationship between working hours and risk of cardiovascular disease is limited.

METHODS AND RESULTS

The Japan Public Health Center-Based Prospective Study Cohort II involved 15,277 men aged 40-59 years at the baseline survey in 1993. Respondents were followed up until 2012. During the median 20 years of follow up (257,229 person-years), we observed 212 cases of acute myocardial infarction and 745 stroke events. Cox proportional hazards models adjusted for sociodemographic factors, cardiovascular risk factors, and occupation showed that multivariable-adjusted hazard ratios (HRs) associated with overtime work of ≥11h/day were: 1.63 (95% confidence interval [CI] 1.01-2.63) for acute myocardial infarction and 0.83 (95% CI 0.60-1.13) for total stroke, as compared with the reference group (working 7 to <9 h/day). In the multivariable model, increased risk of acute myocardial infarction associated with overtime work of ≥11 h/day was more evident among salaried employees (HR 2.11, 95% CI 1.03-4.35) and men aged 50-59 years (HR 2.60, 95% CI 1.42-4.77).

CONCLUSIONS

Among middle-aged Japanese men, working overtime is associated with a higher risk of acute myocardial infarction.

Circulating Inflammation Markers and Risk of Gastric and Esophageal Cancers: A Case-Cohort Study Within the Japan Public Health Center-Based Prospective Study

BACKGROUND

Circulating inflammation proteins may be important mediators or markers of carcinogenic mechanisms. There have been few studies with limited numbers of analytes in patients with upper gastrointestinal (GI) tract tumors. We therefore evaluated risk associations of gastric and esophageal cancers with prediagnostic levels of a wide range of these molecules.

METHODS

We performed a case-cohort analysis within the Japan Public Health Center-Based Prospective Study Cohort II, including incident cases of gastric (n = 446) and esophageal (n = 68) cancers and a random subcohort (n = 774). A total of 64 biomarkers were measured in baseline plasma using Luminex bead-based assays. The median time between blood collection and diagnosis was 8.1 years for gastric cancer and 9.4 years for esophageal cancer. HRs for association with each marker were adjusted for potential confounders using Cox regression.

RESULTS

In separate models, sEGFR and TSLP were nominally associated with gastric cancer risk, and CRP, CXCL11/ITAC, and CCL15/MIP1D were associated with esophageal cancer. However, no association satisfied statistical significance after FDR correction. Associations did not differ by time from blood collection to cancer (<5 vs. ≥5 years).

CONCLUSIONS

Our study failed to identify associations of circulating inflammation markers with risk of upper GI tract tumors.

IMPACT

To date, this is the largest assessment of inflammation-related proteins with gastric and esophageal cancer risks. However, the evaluated molecules may not fully represent the complex inflammation processes preceding malignant transformation. Further investigation of other markers in prospective studies is warranted, as demonstration of associations may have important implications for prevention and treatment of these cancers.

The Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT): Study Design and Participants

Background

Lifestyle and life-environment factors have undergone drastic changes in Japan over the last few decades. Further, many molecular epidemiologic studies have reported that genetic, epigenetic, and other biomarker information may be useful in predicting individual disease risk.

Methods

The Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT) was launched in 2011 to identify risk factors for lifestyle-related disease, elucidate factors that extend healthy life expectancy, and contribute toward personalized healthcare based on our more than 20 years’ experience with the JPHC Study. From 2011 through 2016, a baseline survey was conducted at 16 municipalities in seven prefectures across the country. A self-administered questionnaire was distributed to all registered residents aged 40–74, which mainly asked about lifestyle factors, such as socio-demographic situation, personal medical history, smoking, alcohol and dietary habits. We obtained informed consent from each participant to participate in this long follow-up study of at least 20 years, including consent to the potential use of their residence registry, medical records, medical fee receipts, care insurance etc., and to the provision of biospecimens (blood and urine), including genomic analysis.

Results

As of December 31, 2016, we have established a population-based cohort of 115,385 persons (Response rate 44.1%), among whom 55,278 (47.9% of participants) have provided blood and urine samples. The participation rate was slightly higher among females and in the older age group.

Conclusion

We have established a large-scale population-based cohort for next-generation epidemiological study in Japan.

GWAS identifies two novel colorectal cancer loci at 16q24.1 and 20q13.12

Colorectal cancer (CRC) is the fourth leading cause of cancer mortality worldwide. Genome-wide association studies (GWAS) identified more than 50 CRC loci. However, most of the previous studies were conducted in European population, and host genetic factors among Japanese population are largely remained to be identified. To identify novel loci in the Japanese population, here, we performed a large-scale GWAS using 6692 cases and 27 178 controls followed by a replication analysis using more than 11 000 case-control samples. We found the significant association of 10 loci (P < 5 × 10-8), including 2 novel loci on 16q24.1 (IRF8-FOXF1, rs847208, P = 3.15 × 10-9 and odds ratio = 1.107 with 95% confidence interval (CI) of 1.071-1.145) and 20q13.12 (TOX2, rs6065668, P = 4.47 × 10-11 and odds ratio = 0.897 with 95% CI of 0.868-0.926). Moreover, 35 previously reported single nucleotide polymorphisms (SNPs) in 24 regions were validated in the Japanese population (P < 0.05) with the same risk allele as in the previous studies. SNP rs6065668 was significantly associated with TOX2 expression in the sigmoid colon. In addition, nucleotide substitutions in the regulatory region of TOX2 were predicted to alter the binding of several transcription factors, including KLF5. Our findings elucidate the important role of genetic variations in the development of CRC in the Japanese population.

Contribution of Diabetes to the Incidence and Prevalence of Comorbid Conditions (Cancer, Periodontal Disease, Fracture, Impaired Cognitive Function, and Depression): A Systematic Review of Epidemiological Studies in Japanese Populations

BACKGROUND

Several epidemiological studies have determined the relationship between diabetes and the incidence and/or prevalence of recently identified comorbid conditions (cancer, periodontal disease, fracture, cognitive impairment, and depression). These relationships may vary by country or race/ethnicity. We aimed to systematically review studies in this field conducted with the Japanese population because such a review in the Japanese population has never been undertaken.

METHODS

We conducted systematic literature searches in PubMed and Ichushi-Web databases for studies published until December 2016. Studies comparing the incidence and/or prevalence of the comorbidities among the Japanese population were included. The studies were classified as integrated analyses, cohort studies, case-control studies, or cross-sectional studies.

RESULTS

We identified 33 studies (cancer: 17, periodontal disease: 5, fracture: 5, cognitive impairment: 4, and depression: 2). Although several cohort studies and meta-analyses had assessed the development of cancer in diabetes, there was scant epidemiological evidence for the other conditions. Indeed, only one cohort study each had been conducted for periodontal disease, fracture, and cognitive impairment, whereas other evidence was cross-sectional, some of which was induced from baseline characteristic tables of studies designed for other purposes.

CONCLUSION

In Japan, there is insufficient evidence about the relationship between diabetes and the incidence/prevalence of periodontal disease, fracture, cognitive impairment, and depression. By contrast, several cohort studies and integrated analyses have been conducted for the relationship with cancer. Further studies should be undertaken to estimate the contribution of diabetes on the incidence/prevalence of comorbidities that may be specific to the Japanese population.

Genome-wide association study (GWAS) of ovarian cancer in Japanese predicted regulatory variants in 22q13.1

Genome-wide association studies (GWAS) have identified greater than 30 variants associated with ovarian cancer, but most of these variants were investigated in European populations. Here, we integrated GWAS and subsequent functional analyses to identify the genetic variants with potential regulatory effects. We conducted GWAS for ovarian cancer using 681 Japanese cases and 17,492 controls and found that rs137672 on 22q13.1 exhibited a strong association with a P-value of 1.05 × 10⁻⁷ and an odds ratio of 0.573 with a 95% confidence interval of 0.466–0.703. In addition, three previously reported SNPs, i.e., rs10088218, rs9870207 and rs1400482, were validated in the Japanese population (P < 0.05) with the same risk allele as noted in previous studies. Functional studies including regulatory feature analysis and electrophoretic mobility shift assay (EMSA) revealed two regulatory SNPs in 22q13.1, rs2072872 and rs6509, that affect the binding affinity to some nuclear proteins in ovarian cancer cells. The plausible regulatory proteins whose motifs could be affected by the allele changes of these two SNPs were also proposed. Moreover, the protective G allele of rs6509 was associated with a decreased SYNGR1 expression level in normal ovarian tissues. Our findings elucidated the regulatory variants in 22q13.1 that are associated with ovarian cancer risk.

Body Mass Index and Risks of Incident Ischemic Stroke Subtypes: The Japan Public Health Center-Based Prospective (JPHC) Study

BACKGROUND

The association of body mass index (BMI) with risks of ischemic stroke subtypes have not been established.

METHODS

Cumulative average BMI was calculated using self-reported body weight and height obtained from baseline (Cohort I in 1990, and Cohort II from 1993-1994) and 5- and 10-year questionnaire surveys of Japan Public Health Center-based prospective (JPHC) study. A total of 42,343 men and 46,413 women aged 40-69 years were followed-up for the incidence of lacunar, large-artery occlusive, and cardioembolic strokes. A sub-distribution hazard model was used to estimate sub-distribution hazard ratios (SHRs) and the 95% confidence intervals (CIs).

RESULTS

During a median of 20.0 years of follow-up, we documented 809 and 481 lacunar, 395 and 218 large-artery occlusive, and 568 and 298 cardioembolic strokes in men and women, respectively. After adjustment for baseline age, updated smoking, alcohol consumption, leisure-time physical activity, and histories of hypertension, dyslipidemia, and diabetes mellitus, cumulative average BMI was positively linearly associated with lacunar (trend P = 0.007), large-artery occlusive (trend P = 0.002), and cardioembolic (trend P < 0.001) strokes in men, and with lacunar (trend P < 0.001) and large-artery occlusive (trend P = 0.003) strokes in women. There were approximately two-fold excess risk of cardioembolic stroke in both sexes and of lacunar and large-artery occlusive strokes in women for cumulative average BMI ≥30 kg/m² compared to BMI 23-<25 kg/m².

CONCLUSION

Cumulative average BMI showed a positive linear effect on sub-distribution hazards of lacunar, large-artery occlusive, and cardioembolic strokes in both sexes, except for cardioembolic stroke in women.

Genome-wide association study identifies gastric cancer susceptibility loci at 12q24.11-12 and 20q11.21

Gastric cancer is the third leading cause of cancer mortality in Japan and worldwide. Although previous studies identify various genetic variations associated with gastric cancer, host genetic factors are largely unidentified. To identify novel gastric cancer loci in the Japanese population, herein, we carried out a large‐scale genome‐wide association study using 6171 cases and 27 178 controls followed by three replication analyses. Analysis using a total of 11 507 cases and 38 904 controls identified two novel loci on 12q24.11‐12 (rs6490061, P = 3.20 × 10⁻⁸ with an odds ratio [OR] of 0.905) and 20q11.21 (rs2376549, P = 8.11 × 10⁻¹⁰ with an OR of 1.109). rs6490061 is located at intron 19 of the CUX2 gene, and its expression was suppressed by Helicobacter pylori infection. rs2376549 is included within the gene cluster of DEFB families that encode antibacterial peptides. We also found a significant association of rs7849280 in the ABO gene locus on 9q34.2 (P = 2.64 × 10⁻¹³ with an OR of 1.148). CUX2 and ABO expression in gastric mucosal tissues was significantly associated with rs6490061 and rs7849280 (P = 0.0153 and 8.00 × 10⁻¹¹), respectively. Our findings show the crucial roles of genetic variations in the pathogenesis of gastric cancer.

Comparison of land use regression models for NO2 based on routine and campaign monitoring data from an urban area of Japan

BACKGROUND

Typically, land use regression (LUR) models have been developed using campaign monitoring data rather than routine monitoring data. However, the latter have advantages such as low cost and long-term coverage. Based on the idea that LUR models representing regional differences in air pollution and regional road structures are optimal, the objective of this study was to evaluate the validity of LUR models for nitrogen dioxide (NO₂) based on routine and campaign monitoring data obtained from an urban area.

METHOD

We selected the city of Suita in Osaka (Japan). We built a model based on routine monitoring data obtained from all sites (routine-LUR-All), and a model based on campaign monitoring data (campaign-LUR) within the city. Models based on routine monitoring data obtained from background sites (routine-LUR-BS) and based on data obtained from roadside sites (routine-LUR-RS) were also built. The routine LUR models were based on monitoring networks across two prefectures (i.e., Osaka and Hyogo prefectures). We calculated the predictability of the each model. We then compared the predicted NO₂ concentrations from each model with measured annual average NO₂ concentrations from evaluation sites.

RESULTS

The routine-LUR-All and routine-LUR-BS models both predicted NO₂ concentrations well: adjusted R²=0.68 and 0.76, respectively, and root mean square error=3.4 and 2.1ppb, respectively. The predictions from the routine-LUR-All model were highly correlated with the measured NO₂ concentrations at evaluation sites. Although the predicted NO₂ concentrations from each model were correlated, the LUR models based on routine networks, and particularly those based on all monitoring sites, provided better visual representations of the local road conditions in the city.

CONCLUSION

The present study demonstrated that LUR models based on routine data could estimate local traffic-related air pollution in an urban area. The importance and usefulness of data from routine monitoring networks should be acknowledged.

Coffee drinking and colorectal cancer and its subsites: A pooled analysis of 8 cohort studies in Japan

Coffee is a rich source of bioactive compounds that have potential anticarcinogenic effects. However, it remains unclear whether coffee drinking is associated with colorectal cancer. Also, despite different etiological factors involved in gut physiology, few studies have investigated this association by anatomical site of the lesion. To address these issues, this study examined the association between coffee drinking and colorectal cancer in a pooled analysis from 8 cohort studies conducted in Japan. Among 320,322 participants followed up for 4,503,274 person-years, 6,711 incident colorectal cancer cases were identified. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models and then pooled using the random effects model. Coffee drinking was not materially associated with colorectal cancer risk in men or women (pooled HR 0.92, 95% CI 0.82-1.03 in men and pooled HR 0.90, 95% CI 0.76-1.07 in women). Analysis by subsite showed a lower risk of colon cancer among female drinkers of ≥3 cups coffee/day (pooled HR 0.80, 95% CI 0.64-0.99). There was no such association in men. Coffee drinking was not associated with risk of rectal cancer in men or women. Results were virtually the same among never smokers except for an increased risk of rectal cancer associated with frequent coffee consumption. Coffee drinking may be associated with lower risk of colon cancer in Japanese women.

Body-Mass Index and Pancreatic Cancer Incidence: A Pooled Analysis of Nine Population-Based Cohort Studies With More Than 340,000 Japanese Subjects

Background

A high body mass index (BMI) has been proposed as an important risk factor for pancreatic cancer. However, this association of BMI with pancreatic cancer risk has not been confirmed in Asian populations.

Methods

We evaluated the association between BMI (either at baseline or during early adulthood) and pancreatic cancer risk by conducting a pooled analysis of nine population-based prospective cohort studies in Japan with more than 340,000 subjects. Summary hazard ratios (HRs) were estimated by pooling study-specific HRs for unified BMI categories with a random-effects model.

Results

Among Japanese men, being obese at baseline was associated with a higher risk of pancreatic cancer incidence (≥30 kg/m² compared with 23 to <25 kg/m², adjusted HR 1.71; 95% confidence interval [CI], 1.03–2.86). A J-shaped association between BMI during early adulthood and pancreatic cancer incidence was seen in men. In contrast, we observed no clear association among women, although there may be a positive linear association between BMI at baseline and the risk of pancreatic cancer (per 1 kg/m², adjusted HR 1.02; 95% CI, 1.00–1.05).

Conclusions

Pooling of data from cohort studies with a considerable number of Japanese subjects revealed a significant positive association between obesity and pancreatic cancer risk among men. This information indicates that strategies that effectively prevent obesity among men might lead to a reduced burden of pancreatic cancer, especially in Asian populations.

Impact of Alcohol Intake and Drinking Patterns on Mortality From All Causes and Major Causes of Death in a Japanese Population

BACKGROUND

We examined the associations of alcohol consumption and liver holidays with all-cause mortality and with mortality due to cancer, heart disease, cerebrovascular disease, respiratory disease, and injury using a large-scale prospective study in Japan.

METHODS

We followed 102,849 Japanese who were aged between 40 and 69 years at baseline for 18.2 years on average, during which 15,203 deaths were reported. Associations between alcohol intake and mortality risk were assessed using a Cox proportional hazards model, with analysis by the number of liver holidays (in which a person abstains from drinking for several days a week).

RESULTS

A J-shaped association was observed between alcohol intake and total mortality in men (nondrinkers: reference; occasional drinkers: hazard ratio [HR] 0.74; 95% confidence interval [CI], 0.68-0.80; 1-149 g/week: HR 0.76; 95% CI, 0.71-0.81; 150-299 g/week: HR 0.75; 95% CI, 0.70-0.80; 300-449 g/week: HR 0.84; 95% CI, 0.78-0.91; 450-599 g/week: HR 0.92; 95% CI, 0.83-1.01; and ≥600 g/week: HR 1.19; 95% CI, 1.07-1.32) and in women (nondrinkers: reference; occasional: HR 0.75; 95% CI, 0.70-0.82; 1-149 g/week: HR 0.80; 95% CI, 0.73-0.88; 150-299 g/week: HR 0.91; 95% CI, 0.74-1.13; 300-449 g/week: HR 1.04; 95% CI, 0.73-1.48; and ≥450 g/week: HR 1.59; 95% CI, 1.07-2.38). In current drinkers, alcohol consumption was associated with a linear, positive increase in mortality risk from all causes, cancer, and cerebrovascular disease in both men and women, but not heart disease in men. Taking of liver holidays was associated with a lower risk of cancer and cerebrovascular disease mortality in men.

CONCLUSIONS

Alcohol intake showed J-shaped associations with the risk of total mortality and three leading causes of death. However, heavy drinking increases the risk of mortality, which highlights the necessity of drinking in moderation coupled with liver holidays.

Association between poor psychosocial conditions and diabetic nephropathy in Japanese type 2 diabetes patients: A cross-sectional study

AIMS/INTRODUCTION

It is suggested that a positive psychosocial condition has a good effect on health and glycemic control. However, there has been no research to evaluate the association between positive psychosocial factors and diabetic nephropathy (DN). The aim of the present study was to evaluate the association between psychosocial factors and DN in patients with type 2 diabetes.

MATERIAL AND METHODS

To assess psychosocial condition, six indicators (happiness score, Life Orientation Test-revised score as an indicator of dispositional optimism, laughter frequency, self-awareness of stress, social network and social support) were assessed by a self-administered questionnaire, and associations between these psychosocial indicators and the presence of DN were examined.

RESULTS

A cross-sectional analysis of patients with (n = 123) and without DN (n = 220) showed that a high score for happiness (odds ratio [OR] per 1 standard deviation 0.71, 95% confidence interval [CI] 0.57-0.89, P = 0.003), high Life Orientation Test-revised score (OR per 1 standard deviation 0.77, 95% CI: 0.61-0.98, P = 0.035), less self-awareness of stress (OR 0.56, 95% CI: 0.34-0.90, P = 0.017), high connection of social network (OR 0.55, 95% CI: 0.35-0.87, P = 0.010) and high social support (OR 0.61, 95% CI: 0.38-0.96, P = 0.035) were associated with a reduced risk of prevalence of DN. Similar results were observed even after adjustment for the following conventional risk factors of DN: age, sex, duration of diabetes, hemoglobin A1c, hypertension, dyslipidemia and current smoking.

CONCLUSIONS

The present study showed that five out of six prespecified indicators of psychosocial condition were significantly associated with the presence of DN in Japanese patients with type 2 diabetes.

Fruit and vegetable consumption, Helicobacter pylori antibodies, and gastric cancer risk: A pooled analysis of prospective studies in China, Japan, and Korea

Epidemiological findings on the association between fruit and vegetable consumption and gastric cancer risk remain inconsistent. The present analysis included 810 prospectively ascertained non-cardia gastric cancer cases and 1,160 matched controls from the Helicobacter pylori Biomarker Cohort Consortium, which collected blood samples, demographic, lifestyle, and dietary data at baseline. Conditional logistic regression adjusting for total energy intake, smoking, and H. pylori status, was applied to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for gastric cancer risk across cohort- and sex-specific quartiles of fruit and vegetable intake. Increasing fruit intake was associated with decreasing risk of non-cardia gastric cancer (OR = 0.71, 95% CI: 0.52-0.95, p trend = 0.02). Compared to low-fruit consumers infected with CagA-positive H. pylori, high-fruit consumers without evidence of H. pylori antibodies had the lowest odds for gastric cancer incidence (OR = 0.12, 95% CI: 0.06-0.25), whereby the inverse association with high-fruit consumption was attenuated among individuals infected with CagA-positive H. pylori (OR = 0.82, 95% CI: 0.66-1.03). To note, the small number of H. pylori negative individuals does influence this finding. We observed a weaker, nondose-response suggestion of an inverse association of vegetable intake with non-cardia gastric cancer risk. High fruit intake may play a role in decreasing risk of non-cardia gastric cancer in Asia.

Cigarette smoking and risk of coronary heart disease incidence among middle-aged Japanese men and women: the JPHC Study Cohort I

BACKGROUND

Few data have been available on the sex-specific magnitude of the smoking effect on the risk of coronary heart disease (CHD) in Asia.

DESIGN AND METHODS

A population-based prospective cohort study of 19 782 men and 21 500 women aged 40-59 years between 1990-1992 and 2001 was conducted to examine the relationship between smoking status and the risk of CHD.

RESULTS

A total of 260 incidences of CHD were confirmed among men, including 174 myocardial infarctions (MI). The numbers among women were 66 and 43, respectively. The multivariate relative risk [95% confidence interval (CI)] for current smokers versus never-smokers in men after adjustment for cardiovascular risk factors, several life style factors and public health centre was 2.85 (1.98, 4.12) for total CHD and 3.64 (2.27, 5.83) for MI. These respective risks in women were 3.07 (1.48, 6.40) and 2.90 (1.18, 7.18). Among men, a dose-dependent relationship was observed between the number of cigarettes and the risk of MI. The population-attributable risk per cent (95% CI) of CHD was 46% (34, 55) in men and 9% (0, 18) in women. Smoking cessation, however, led to a rapid decline in the CHD risk within 2 years.

CONCLUSION

Smoking raises the risk of CHD significantly in both sexes of middle-aged Japanese, with large public health significance especially in men. Smoking cessation would have an immediate effect on risk reduction.

Helicobacter pylori blood biomarker for gastric cancer risk in East Asia

BACKGROUND

Incidence and mortality rates for gastric cancer, the fifth most commonly diagnosed and third most deadly cancer worldwide, are highest in East Asia. We sought to identify gastric cancer risk biomarkers among eight prospective studies from China, Japan and Korea.

METHODS

This pooled nested case-control study included 1608 incident non-cardia gastric cancer cases and 1958 matched controls. Pre-diagnostic antibody levels to 15 Helicobacter pylori proteins were assessed using multiplex serology. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Sero-positivity to 10 H. pylori antigens (Omp, CagA, VacA, HcpC, HP 0305, GroEL, NapA, HyuA, Cad, HpaA) was associated with a 1.29- to 3.26-fold increase in odds of gastric cancer. Omp and HP 0305 consistently remained associated with gastric cancer risk after mutually adjusting for all other markers. Sero-positivity to both Omp and HP 0305 was associated with an over 4-fold increase in gastric cancer incidence (OR, 4.09; 95% CI 3.26-5.13). When limited to only those who are CagA+ H. pylori+, Omp/HP 0305 sero-positivity remained strongly associated with an over 3-fold increase in the odds of gastric cancer (OR, 3.34; 95% CI 2.27-4.91). The results were highly consistent among the cohorts.

CONCLUSIONS

We have confirmed new H. pylori biomarkers that are strongly associated with gastric cancer risk, even among those infected with the known H. pylori virulence factor CagA. These results may help to design cost-efficient prevention strategies to reduce gastric cancer incidence in East Asia.

Educational Levels and Risk of Suicide in Japan: The Japan Public Health Center Study (JPHC) Cohort I

BACKGROUND

Suicide rates have been related to educational level and other socioeconomic statuses. However, no prospective study has examined the association between educational level and the risk of suicide in Japan.

METHODS

We examined the association of education level and suicide risk in a population-based cohort of Japanese men and women aged 40-59 years in the Japan Public Health Center-based Prospective Study Cohort I. In the baseline survey initiated in 1990, a total of 46 156 subjects (21 829 men and 24 327 women) completed a self-administered questionnaire, which included a query of educational level, and were followed up until the end of December 2011. Educational levels were categorized into four groups (junior high school, high school, junior or career college, and university or higher education). During a median follow-up of 21.6 years, the hazard ratios (HRs) and 95% confidence intervals (CIs) of suicide according to educational level were estimated using the Cox proportional hazards regression model adjusted for age; study area; previous history of stroke, ischemic heart disease, or cancer; self-reported stress; alcohol consumption; smoking; living with spouse; and employment status. A total of 299 deaths attributed to suicide occurred.

RESULTS

The HR for university graduates or those with higher education versus junior high school graduates was 0.47 (95% CI, 0.24-0.94) in men, and that for high school graduates versus junior high school graduates was 0.44 (95% CI, 0.24-0.79) in women.

CONCLUSIONS

High educational levels were associated with a reduced risk of suicide for both Japanese men and women.

Active recruitment and limited participant-load related to high participation in large population-based biobank studies

OBJECTIVES

Insight into baseline participation rates and their determinants is crucial for designing future population-based biobank studies. We therefore conducted a systematic review and meta-analysis of baseline participation rates and their determinants in large longitudinal population-based biobank studies.

STUDY DESIGN AND SETTING

We screened studies registered within the Public Population Project in Genomics and Society and in the Biobanking and Biomolecular Resources Research Infrastructure catalogues to find potentially eligible studies. We retrieved data with regard to participation rate, biobank design, performed measurements, and specific strategies for improving participation. We calculated weighted pooled proportions for each determinant using random-effects models.

RESULTS

We included 25 studies (participation rates 5-96%). Participation rates were highest for studies involving face-to-face recruitment [82.6%; 95% confidence interval (CI): 72.2%, 90.9%], for studies in which participants were visited for an examination (77.5%; 95% CI: 64.0%, 88.6%) and for studies in which at maximum four measurements were performed (78.2%; 95% CI: 69.7%, 85.7%). Specific strategies to improve participation were not found to be associated with higher participation rates.

CONCLUSION

Specific choices of recruitment methods and design have consequences for participation rates. These insights may help to increase participation in future studies, thereby enhancing the validity of their findings.

Time Spent Walking and Risk of Diabetes in Japanese Adults: The Japan Public Health Center-Based Prospective Diabetes Study

Background

The association between time spent walking and risk of diabetes was investigated in a Japanese population-based cohort.

Methods

Data from the Japan Public Health Center-based Prospective Diabetes cohort were analyzed. The surveys of diabetes were performed at baseline and at the 5-year follow-up. Time spent walking per day was assessed using a self-reported questionnaire (<30 minutes, 30 minutes to <1 hour, 1 to <2 hours, or ≥2 hours). A cross-sectional analysis was performed among 26 488 adults in the baseline survey. Logistic regression was used to examine the association between time spent walking and the presence of unrecognized diabetes. We then performed a longitudinal analysis that was restricted to 11 101 non-diabetic adults who participated in both the baseline and 5-year surveys. The association between time spent walking and the incidence of diabetes during the 5 years was examined.

Results

In the cross-sectional analysis, 1058 participants had unrecognized diabetes. Those with time spent walking of <30 minutes per day had increased odds of having diabetes in relation to those with time spent walking of ≥2 hours (adjusted odds ratio [OR] 1.23; 95% CI, 1.02–1.48). In the longitudinal analysis, 612 participants developed diabetes during the 5 years of follow-up. However, a significant association between time spent walking and the incidence of diabetes was not observed.

Conclusions

Increased risk of diabetes was implied in those with time spent walking of <30 minutes per day, although the longitudinal analysis failed to show a significant result.

Determinant factors of the difference between self-reported weight and measured weight among Japanese

OBJECTIVES

To assess the difference between self-reported and measured weight values in Japanese men and women and to determine the underlying determinants of the differences between self-reported and measured values.

METHODS

The data were collected from 363 general Japanese individuals aged 16-88 years living in Kumamoto prefecture. Participants completed a self-administered questionnaire designed for this study with self-reported weight and height values. Measured weight and height were measured immediately after questionnaire completion. Paired t-tests identified differences between self-reported and measured values by sex. Multiple-stepwise regression analysis examined the independent variables' effects on the differences between self-reported and measured weights.

RESULTS

Significant differences were found between self-reported and measured values for both sexes (p < 0.001). There was a significant negative relationship between the difference in an individual's self-reported and measured weight in each sex, with higher measured weight individuals more likely to underestimate their weight. Multiple-stepwise regression analysis models explained 12.1 % (p < 0.01), 11.3 % (p < 0.01), and 5.6 % (p < 0.01) of the variance in all participants, men, and women, respectively. Significant effects were found for age, weight measurement frequency, and measured weight in total participants, weight measurement frequency, and measured weight for men, and age for women.

CONCLUSIONS

In this study, the mean absolute value of the weight and height variances proved the unreliability of self-reported weight and height values. This study's findings suggest self-reported weight inaccuracy especially for obese populations. This should be adjusted when using it in epidemiological studies and healthcare planning.

Prediction of the 10-year probability of gastric cancer occurrence in the Japanese population: the JPHC study cohort II

Gastric cancer is a particularly important issue in Japan, where incidence rates are among the highest observed. In this work, we provide a risk prediction model allowing the estimation of the 10-year cumulative probability of gastric cancer occurrence. The study population consisted of 19,028 individuals from the Japanese Public Health Center cohort II who were followed-up from 1993 to 2009. A parametric survival model was used to assess the impact on the probability of gastric cancer of clinical and lifestyle-related risk factors in combination with serum anti-Helicobacter pylori antibody titres and pepsinogen I and pepsinogen II levels. Based on the resulting model, cumulative probability estimates were calculated and a simple risk scoring system was developed. A total of 412 cases of gastric cancer occurred during 270,854 person-years of follow-up. The final model included (besides the biological markers) age, gender, smoking status, family history of gastric cancer and consumption of highly salted food. The developed prediction model showed good predictive performance in terms of discrimination (optimism-corrected c-index: 0.768) and calibration (Nam and d'Agostino's χ(2) test: 14.78; p values = 0.06). Estimates of the 10-year probability of gastric cancer occurrence ranged from 0.04% (0.02, 0.1) to 14.87% (8.96, 24.14) for men and from 0.03% (0.02, 0.07) to 4.91% (2.71, 8.81) for women. In conclusion, we developed a risk prediction model for gastric cancer that combines clinical and biological markers. It might prompt individuals to modify their lifestyle habits, attend regular check-up visits or participate in screening programmes.