Role of Polyunsaturated Fat in Modifying Cardiovascular Risk Associated With Family History of Cardiovascular Disease: Pooled De Novo Results From 15 Observational Studies.

BACKGROUND: It is unknown whether dietary intake of polyunsaturated fatty acids (PUFA) modifies the cardiovascular disease (CVD) risk associated with a family history of CVD. We assessed interactions between biomarkers of low PUFA intake and a family history in relation to long-term CVD risk in a large consortium. METHODS: Blood and tissue PUFA data from 40 885 CVD-free adults were assessed. PUFA levels ≤25th percentile were considered to reflect low intake of linoleic, alpha-linolenic, and eicosapentaenoic/docosahexaenoic acids (EPA/DHA). Family history was defined as having ≥1 first-degree relative who experienced a CVD event. Relative risks with 95% CI of CVD were estimated using Cox regression and meta-analyzed. Interactions were assessed by analyzing product terms and calculating relative excess risk due to interaction. RESULTS: After multivariable adjustments, a significant interaction between low EPA/DHA and family history was observed (product term pooled RR, 1.09 [95% CI, 1.02-1.16]; P=0.01). The pooled relative risk of CVD associated with the combined exposure to low EPA/DHA, and family history was 1.41 (95% CI, 1.30-1.54), whereas it was 1.25 (95% CI, 1.16-1.33) for family history alone and 1.06 (95% CI, 0.98-1.14) for EPA/DHA alone, compared with those with neither exposure. The relative excess risk due to interaction results indicated no interactions. CONCLUSIONS: A significant interaction between biomarkers of low EPA/DHA intake, but not the other PUFA, and a family history was observed. This novel finding might suggest a need to emphasize the benefit of consuming oily fish for individuals with a family history of CVD.

Association of depressive symptoms with incident fractures: the Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT).

This 5-year longitudinal study investigated the relationship between depressive symptoms and fracture risk in a large Japanese cohort. Depressive symptoms were a significant risk factor for hip fractures in women. PURPOSE: A relationship between depressive symptoms and fractures has not been clearly demonstrated. We aimed to investigate the relationship between depressive symptoms and 5-year fracture risk in the Japan Public Health Center-based Prospective Study for the Next Generation. METHODS: From 2011 to 2016, 114,092 participants were enrolled, and a follow-up survey was conducted 5 years later. We analyzed 30,552 men and 38,063 women aged 40-74 years who had no past fractures at baseline. Presence of depressive symptoms was defined as a modified 11-item Center for Epidemiological Studies Depression Scale score of 8 or higher, a history of depression, or use of antidepressants. Subjects were asked to report vertebral, upper limb, and/or hip fractures, except for traffic or work accidents, that occurred during the follow-up period. The adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for fracture were analyzed via logistic regression analysis to evaluate the relationship between depressive symptoms and fracture. RESULTS: Women with depressive symptoms demonstrated a high AOR for hip fractures (AOR: 2.78, 95% CI: 1.30 - 5.92); this result was consistent in post menopause women. In men, this association was not found for any age group or any type of fracture. CONCLUSIONS: Depressive symptoms in women may increase the risk of hip fractures. Further studies are required to explore this relationship in more detail.

Fruit and Vegetable Intake and Risk of Disabling Dementia: Japan Public Health Center Disabling Dementia Study.

BACKGROUND: Fruits and vegetables contain abundant amounts of antioxidant vitamins such as vitamin C, α-carotene, and ß-carotene. Few prospective observational studies have investigated the effects of fruit and vegetable intake on the risk of dementia, and the results are inconsistent. OBJECTIVES: Our aim was to examine associations between fruit and vegetable intake and the risk of disabling dementia. METHODS: We conducted a follow-up survey within the Japan Public Health Center-based Prospective Study involving 42,643 individuals aged 50-79 y at baseline (2000-2003). Dietary fruit and vegetable intakes and related antioxidant vitamin intakes (i.e., α-carotene, ß-carotene, and vitamin C) were determined using a food frequency questionnaire. The diagnosis of disabling dementia was made based on the daily living disability status related to dementia under the Japanese long-term care insurance program from 2006 to 2016. Hazard ratios and 95% confidence intervals for disabling dementia were estimated using area-stratified Cox proportional hazard models adjusted for potential confounding factors. RESULTS: A total of 4994 cases of disabling dementia were recorded. We observed an inverse association between total fruit and vegetable intake and the risk of dementia among males and females: the multivariate hazard ratios (95% confidence intervals) for the highest compared with lowest quartiles of intake were 0.87 (0.76, 0.99) (P- trend = 0.05) among males and 0.85 (0.76, 0.94) (P- trend = 0.006) among females. Among antioxidant vitamins, vitamin C intake was inversely associated with the risk of dementia among males and females: the multivariate hazard ratios (95% confidence intervals) for the highest compared with lowest quartiles of intake were 0.71 (0.61, 0.84) (P- trend < 0.0001) among males, and 0.76 (0.67, 0.86) (P- trend < 0.0001) among females. CONCLUSIONS: Fruit and vegetable intake and dietary intake of vitamin C may contribute to reducing the risk of disabling dementia among males and females.

Sleep duration, its change, and risk of dementia among Japanese: The Japan Public Health Center-based Prospective Study.

OBJECTIVE: Previous findings on the association between sleep duration, changes in sleep duration, and long-term dementia risk were mixed. Thus, we aimed to investigate the association between midlife sleep duration, its change, and dementia. METHODS: We recruited 41,731 Japanese (40-71 years) and documented their habitual sleep duration at baseline (1990-1994) and a 5-year follow-up survey. Changes in sleep duration were calculated as differences between baseline and 5-year measurements. We identified dementia using the Long-Term Care Insurance system (2007-2016). Hazard ratios (HRs) and 95% confidence intervals (CIs) of dementia were calculated using the area-stratified Cox model. RESULTS: During 360,389 person-years, 4621 participants exhibited dementia. The multivariable HRs of dementia compared with 7 h of sleep were 1.13 (95% CI: 0.98-1.30) for 3-5 h, 0.93 (0.85-1.02) for 6 h, 1.06 (0.99-1.14) for 8 h, 1.13 (1.01-1.27) for 9 h, and 1.40 (1.21-1.63) for 10-12 h with a J-shaped fashion (p for linear < 0.001 and quadratic < 0.001). For its change, the HRs compared with no change were 1.02 (0.90-1.16) for decreased ≥2 h, 0.95 (0.88-1.03) for decreased 1 h, 1.00 (0.91-1.09) for increased 1 h, and 1.37 (1.20-1.58) for increased ≥2 h. The positive association for decreased sleep duration was observed in individuals with an initial sleep duration of ≤7 h, but not in those with ≥8 h (p for interaction = 0.007). CONCLUSIONS: Long and increased sleep duration was associated with a higher risk of dementia.

Mushroom intake and risk of incident disabling dementia: the Circulatory Risk in Communities Study (CIRCS).

It is uncertain whether dietary intake of mushrooms rich in dietary fibre and several antioxidants is associated with a lower risk of dementia. We sought to examine prospectively the association between mushroom intake and the risk of disabling dementia. We performed a prospective study involving 3750 people aged 40 to 64 years residing in three communities who participated in an annual cardiovascular risk survey from 1985 to 1999. Cases of incident disabling dementia were surveyed from 1999 to 2020. We calculated the hazard ratios (HR) and 95 % CI for incident total dementia according to mushroom intake among participants with or without a history of stroke. During a mean 16·0 years' follow-up in 3739 eligible participants, 670 people developed disabling dementia. For women, mushroom intake was inversely associated with the risk of total dementia and the association was confined to dementia without a history of stroke. The multivariable HR (95 % CI) for total dementia in women were 0·81 (0·62, 1·06) for mushroom intake of 0·1-14·9 g/d and 0·56 (0·42, 0·75) for mushroom intake above 15·0 g/d (Pfor trend = 0·003) compared with no intake. The corresponding HR (95 % CI) for dementia without a history of stroke were 0·66 (0·47, 0·93) and 0·55 (0·38, 0·79) (Pfor trend = 0·01). In men, no associations were observed between mushroom intake and the risk of disabling dementia. Among Japanese women, dietary mushroom intake was associated with a lower risk of disabling dementia.

Different trends in suicide rates among foreign residents in Japan and Japanese citizens during the COVID-19 pandemic.

BACKGROUND: Suicide rates in Japan have increased during the COVID-19 pandemic, and foreign residents may be more vulnerable to mental stress during such crises. Therefore, we aimed to compare the trends in suicide rates during the COVID-19 pandemic between foreign residents and Japanese citizens. METHODS: Vital statistics of Japan data from January 1, 2016 to December 31, 2021 were used to calculate quarterly sex-specific suicide rates for foreign residents and Japanese citizens. An event-study analysis was conducted to evaluate whether suicide rates during the COVID-19 pandemic increased compared to pre-pandemic estimates; foreign residents and Japanese citizens were compared using difference-in-difference-in-differences estimates. RESULTS: Between 2016 and 2021, 1,431 foreign residents and 121,610 Japanese citizens died from suicide in Japan. Although the suicide rate for foreign residents was lower than that for Japanese citizens, Korean residents, who comprise approximately half of the foreign decedents, had largely higher suicide rates than Japanese citizens. The event-study analysis indicated that suicide rates increased among foreign residents for both men and women, and continued for men by the end of 2021. In Japanese citizens, after a decline in suicide rates in the second quarter of 2020, suicide rates increased both among men and women, and lasted for women until the fourth quarter of 2021. The difference-in-difference-in-differences analyses confirmed the initial decline in the second quarter of 2020 in suicide rate only in Japanese men and women, and the persistent increase through 2021 in foreign men. CONCLUSIONS: We found differential trends in suicide rates between foreign and Japanese men and women during the COVID-19 pandemic featuring a persistent increase in foreign men. Suicide prevention measures should be focused on these high-risk subpopulations.

Validity of self-reported participation in cancer screenings and health checkups in Japan.

BACKGROUND: The participation rate for screening is regarded as a useful indicator for preventing cancer and cardio-metabolic disease. However, the validity of self-reported screening participation has not yet been thoroughly evaluated in Japan. We aimed to examine its validity using the municipal screening records among the Japanese population. METHODS: We included 3,060 men and 3,860 women insured by the National Health Insurance for residents aged <75 years or the Medical Care System for the Elderly aged ≥75 years in the Chikusei area of the Japan Public Health Center-based Prospective Study for the Next Generation. They were asked about their participation in cancer screenings and health checkups during the previous year. We compared their responses to the municipal records and calculated the sensitivity and specificity of self-reported screening participation. RESULTS: The sensitivity and specificity of self-reported participation were 0.49 and 0.86 for lung cancer screening; 0.67 and 0.85 for colorectal cancer screening; 0.77 and 0.79 for stomach cancer screening; and 0.86 and 0.65 for health checkup, respectively. Among women, the sensitivity and specificity were 0.83 and 0.81 for breast cancer and 0.85 and 0.90 for cervical cancer, respectively. CONCLUSION: Self-reported cancer screening participation for colorectal, stomach, breast, and cervical cancers had moderate-high sensitivity and specificity. Self-reported participation, especially for lung cancer screening and health checkups, should be carefully interpreted when assessing the performance of preventive measures.

Validity of Self-reported Helicobacter pylori Eradication Treatment From Questionnaire and Interview Surveys of the JPHC-NEXT Study: Comparison With Prescription History From Insurance Claims Data.

BACKGROUND: We aimed to evaluate the validity of self-administered questionnaire surveys and face-to-face interview surveys for the detection of Helicobacter pylori eradication therapy. METHODS: Participants were a cohort, aged 40-74 years, living in three different locations of Japan, who took part in the baseline survey (2011-2012) of the Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT). Five years after the baseline survey, a questionnaire and interview survey were independently conducted to determine the history of Helicobacter pylori eradication treatment over the 5-year period. Prescription of Helicobacter pylori eradication medications in national insurance claims data from the baseline survey to the 5-year survey was used as a reference standard. RESULTS: In total, 15,760 questionnaire surveys and 8,006 interview surveys were included in the analysis. There were 3,471 respondents to the questionnaire and 2,398 respondents to the interview who reported having received Helicobacter pylori eradication treatment within the past 5 years. Comparison of the questionnaire survey to national insurance claims data showed a sensitivity of 95.1% (2,213/2,328), specificity of 90.6% (12,174/13,432), positive predictive value of 63.8% (2,213/3,471), negative predictive value of 99.1% (12,174/12,289), and Cohen's Kappa value of 0.71. Respective values of the interview survey were 94.4% (1,694/1,795), 88.7% (5,507/6,211), 70.6% (1,694/2,398), 98.2% (5,507/5,608), and 0.74. CONCLUSION: Both the questionnaire and the interview showed high sensitivity, high specificity, and good agreement with the insurance claim prescriptions data. Some participants may have received eradication treatment without going through the public insurance claim database, resulting in a low positive predictive value.

Serum folate and risk of disabling dementia: a community-based nested case-control study.

PURPOSE: The aim of this study was to examine associations between serum folate levels and risk of disabling dementia that required care under the national insurance (disabling dementia). METHODS: We performed a nested case-control study in a community-based cohort, the Circulatory Risk in Communities Study, involving 13,934 Japanese individuals aged 40-84 years at the baseline period of 1984-2005. Serum folate was measured in 578 cases of incident disabling dementia, and in 1,156 controls whose age (±1 years), sex, area of residence, and baseline year were matched with the cases. The diagnosis of disabling dementia was performed by attending physicians under the National Long-Term Care Insurance System in Japan. Conditional odds ratios of disabling dementia according to quintiles of serum folate were calculated using conditional logistic regression models. RESULTS: After a 20.8-year follow-up, serum folate was inversely associated with risk of disabling dementia. The respective multivariable odds ratios (95% CIs) were 0.71 (0.51-0.99), 0.76 (0.54-1.06), 0.70 (0.49-1.00), and 0.62 (0.43-0.90) for persons with the second, third, fourth, and highest quintiles of serum folate as compared with the lowest quintile (P for trend = 0.03). A similar association was observed for dementia with or without stroke. CONCLUSION: In this nested case-control study with a long follow-up, low serum folate levels were associated with an increased risk of disabling dementia among Japanese individuals.

Relationship between Ikigai and longitudinal changes in serum HDL cholesterol levels: the Circulatory Risk in Communities Study (CIRCS).

BACKGROUND: Having positive psychological well-being has been associated with serum high-density lipoprotein cholesterol (HDLC), but no longitudinal study to date has examined the association between Ikigai and serum HDLC. Therefore, we examined the association between Ikigai and change in serum HDLC over time using a cohort dataset spanning 2010-2018. METHODS: The study included 471 men and 776 women aged 40-74 years who underwent a cardiovascular examination in 2010 and were asked their levels of Ikigai. We combined "definitely yes" and "yes" as "with Ikigai" and recorded "a little" as "with a little Ikigai" and "no" as "without Ikigai". We measured serum HDLC using direct methods. The association between Ikigai and serum HDLC levels at baseline, and changes in this relationship during an eight-year period, were analyzed using linear mixed-effect models. RESULTS: At the baseline, relative to those without Ikigai, women with Ikigai had higher serum HDLC (baseline difference in those with a little Ikigai = 7.52 mg/dl, 95% confidence interval [CI]: 1.12 to 13.9 and in those with Ikigai = 8.11 mg/dl, 95% CI: 1.54 to 14.7). The difference in serum HDLC between women with and without Ikigai remained over the eight-year follow-up period. There were no similar Ikigai-associated differences in the serum HDLC of men. CONCLUSIONS: Women with Ikigai showed differences in serum HDLC that were observed at baseline and persisted over time.

The effect of age on the relationship between body mass index and risks of incident stroke subtypes: The JPHC study.

OBJECTIVE: The associations between body mass index (BMI) and stroke subtypes, particularly intracerebral hemorrhage, have not been consistent. Such inconsistencies may be due to differences in the age at which BMI was obtained. We examined the possible age modifications in the association between BMI and stroke risk. MATERIALS AND METHODS: We followed 88,754 participants, aged 40-69 years at baseline (1990-1994), of the Japan Public Health Center-based prospective (JPHC) study for stroke incidence. BMI was obtained using self-reported body weight and height, which were categorized using the following cut-off points: 18.5, 21, 23, 25, 27.5, and 30 kg/m2. Time-dependent Cox proportional hazards models that updated BMI and covariates using 5- and 10-year questionnaire responses were used to estimate hazard ratios and 95 % confidence intervals. The analyses were stratified by age group (40-59 and ≥60 years) and the age of the individuals was updated. RESULTS: During the median follow-up period of 19 years, we documented 4,690 strokes, including 2,781 ischemic strokes and 1,358 intracerebral hemorrhages. After adjusting for sex, age, smoking, alcohol consumption, leisure-time physical activity, history of hypertension, dyslipidemia, and diabetes mellitus, we observed a positive linear association between BMI and ischemic stroke (linear trend, p < 0.001) in both age groups (interaction p>0.05). In contrast, a curvilinear association between BMI and intracerebral hemorrhage was observed in both the middle (curvilinear trend, p=0.017) and the older group (curvilinear trend, p=0.098) (interaction p>0.05). CONCLUSION: BMI and stroke associations did not vary significantly with age, although the association may differ according to subtype.

Longitudinal trajectories of smoking status using 25 year annually-updated data and all-cause mortality followed over 30 years: A community-based prospective cohort study.

We aimed to evaluate the long-term risk of smoking for all-cause mortality according to smoking status trajectories using 25-year annually-repeated input, traced by group-based trajectory modeling with an extension to account for non-random participant attrition or truncation due to death. We examined 2682 men and 4317 women aged 40 to 59 years who participated in annual health checks for the community-based prospective cohort study, 1975-1984 enrollment in Japan. The main outcome measure was all-cause mortality (follow-up period: median 30.2 years in men and 32.2 years in women). We traced annual smoking trajectories, stratified by sex and smoking status at baseline. For smokers at baseline, we identified five trajectories in both sexes, with different patterns of smoking cessation (e.g., early quitters and lifelong smokers). We calculated HRs and 95% CI of all-cause mortality using Cox proportional hazards regression modeling adjusted for age, body mass index, alcohol intake, blood pressure category, dyslipidemia and glucose category. Compared with one-time-point-based smokers, trajectory-based lifelong smokers had an increased risk of all-cause mortality; HRs were 1.31 (95% CI, 1.18-1.46) in men and 1.26 (95% CI, 0.91-1.73) in women. Among community residents aged 40 to 59 years, 25-year-trajectory-based lifelong smokers had an approximately 30% increased risk for all-cause mortality compared to one-time-point-based smokers. Risk of all-cause mortality among smokers with earlier cessation varied materially. It is necessary to consider the trajectories of smoking status to clarify the long-term excess risk of smoking.

Impact of Cardiovascular Disease on the Death Certificate Diagnosis of Heart Failure, Ischemic Heart Disease, and Cerebrovascular Disease　- The Japan Public Health Center-Based Prospective Study.

BACKGROUND: There is considerable interest in the trending discrepancy between ischemic heart disease (IHD) and heart failure (HF) in vital statistics. Clinically, acute myocardial infarction (AMI) and stroke are closely associated with HF, but their contribution to HF as the underlying cause of death (UCD) is unclear.Methods and Results: In 1990 and 1992-1993, we enrolled a total of 140,420 residents of Japanese nationality (aged 40-69 years) from 11 public health center areas. We prospectively examined the occurrence of cardiovascular disease (CVD), including AMI, sudden cardiac death within 1 h (SCD), and stroke, and analyzed the 14,375 participants without a history of CVD at baseline who died during the 20-year follow-up. A time-dependent Cox proportional hazards model was used to estimate hazard ratios and the population attributable fraction (PAF) of AMI, AMI+SCD, stroke, and CVD for deaths due to HF, IHD, and cerebrovascular disease as the UCD, adjusted for individuals' lifestyles and comorbid conditions. The PAF of AMI for HF deaths was 2.4% (95% confidence interval [CI] 1.7-2.9%), which increased to 12.0% (95% CI 11.6-12.2%) for AMI+SCD. The PAF of CVD-attributed HF deaths was estimated to be 17.6% (95% CI 15.9-18.9%). CONCLUSIONS: HF as the UCD was partly explained by CVD. The data imply that most HF deaths reported in vital statistics may be associated with underlying causes other than CVD.

Prospective cohort study on potato intake and mortality from cardiovascular diseases: the Japan Collaborative Cohort Study (JACC study).

PURPOSE: The association between potato intake and risk of cardiovascular diseases is unknown. This study aimed to examine the association between potatoes intake and mortality from stroke and coronary heart disease among Japanese. METHODS: The study included 74,750 participants of the Japan Collaborative Cohort Study, aged 40-79, who were initially free of cardiovascular diseases or cancer at baseline (1988-1990) and provided information on their potato intake. Hazard ratios and 95% confidence intervals were estimated by fitting a Cox proportional hazards model according to the frequency of potatoes intake (0, 0.4, 1.5, 3.5 and 7 servings per week) adjusting for geographic location, age, body mass index, drinking status, smoking status, perceived mental stress, education level, walking time, dietary intakes of total energy, meat, fish, vegetables, fruit, dairy products, cakes, and salt. RESULTS: Over a median of 19.2 years of follow-up, 4908 deaths from cardiovascular diseases were identified: 1019 from coronary heart diseases and 2153 from strokes (738 ischemic strokes and 495 hemorrhagic strokes). After adjustment for potential confounding factors, the hazard ratio of mortality from cardiovascular diseases for daily potato intake compared with no potato intake was 0.82 (95% confidence interval: 0.70, 0.95) among women, and 1.01 (0.88, 1.16) among men. Among women, the multivariable hazard ratios were 0.67 (0.48, 0.96) for coronary heart disease, 0.83 (0.66-1.05) for total stroke, 0.70 (0.43-1.15) for hemorrhagic stroke, and 0.75 (0.49-1.13) for ischemic stroke. CONCLUSION: We found an inverse association of potato intake with mortality from total cardiovascular diseases, especially that from coronary heart disease, among Japanese women. To our knowledge, this is the first report to show an inverse association between potato intake and total cardiovascular diseases.

Alcohol consumption from midlife and risk of disabling dementia in a large population-based cohort study in Japan.

OBJECTIVES: The association between alcohol consumption and dementia in Japanese is poorly understood, and use of single-point alcohol assessment may cause measurement error. We explored this association in Japanese using repeated alcohol assessments. METHODS: Participants in the Japan Public Health Center-based Prospective Study (JPHC Study) since 1990 and who were alive in 2006 were followed from 2006 until 2016 for dementia ascertainment. Disabling dementia was identified through long-term care insurance records. Alcohol consumption was assessed at the 5-year questionnaire survey (1995-1999) and drinking patterns were assessed on repeated follow-up (2000-2003). We performed Cox proportional hazards models with age as the time-scale with adjustment for various lifestyle factors and medical history using light consumption (<75 g ethanol/week, hereinafter "g") as reference. Analysis considering death as a competing risk was also conducted. RESULTS: Among 42,870 participants aged 54-84 years, 4802 cases of disabling dementia were newly diagnosed. Average years from alcohol assessment until dementia incidence was 14.9 years. Non-drinkers and regular drinkers with ≥450 g at 5 years had adjusted HRs (95% CI) of 1.29 (1.12-1.47) and 1.34 (1.12-1.60). Patterns of long-term abstinence, former drinking, and regular heavy weekly consumption of ≥450 g showed increased adjusted HRs of 1.61 (1.28-2.03), 2.54 (1.93-3.35), and 1.96 (1.49-2.59), respectively. Competing risk analysis yielded similar results. CONCLUSIONS: In Japanese, non-drinking and regular weekly consumption of ≥450 g from midlife were associated with high risk of disabling dementia compared with light drinking.

Breastfeeding in Infancy in Relation to Subsequent Physical Size: A 20-year Follow-up of the Ibaraki Children's Cohort Study (IBACHIL).

BACKGROUND: Breastfeeding is said to prevent overweight and obesity in childhood but the evidence about its long-term impact on body size into adolescence and adulthood is scarce. We sought to examine the association between feeding types and subsequent physical size at the ages of 3, 6, 12, and 22 years. METHODS: The Ibaraki Children's Cohort (IBACHIL) Study, which began in 1992, involved a cohort of 4,592 Japanese children from 87 communities of a single prefecture whose parents answered health questionnaires about their child's health and life habits at the age of 3 years. Follow-up questionnaires were distributed to the same cohort when they were 6, 12, and 22 years old. Self-reported height and weight, body mass index (BMI), and overweight status at ages of 3 (n = 4,290), 6 (n = 1,999; proportion of participants analyzed = 47%), 12 (n = 2,227; 52%), and 22 (n = 1,459; 34%) years were compared according to feeding type (breastfeeding, formula feeding, and mixed feeding) during infancy. RESULTS: At the age of 3 years, multivariable adjusted-mean weight and prevalence of overweight were less for breastfed children than those formula-fed in both boys (weight: 14.6 kg vs 14.7 kg, P = 0.07, overweight: 6.3% vs 9.3%, P = 0.03) and in girls (14.0 kg vs 14.2 kg, P = 0.01 and 10.4% vs 13.6%, P = 0.06). However, there were no statistically significant differences in weight, BMI, and overweight at the ages of 6, 12, and 22 years according to feeding type. CONCLUSION: Breastfeeding may prevent overweight in childhood, but its impact is not significant in adolescence and adulthood.

Association Between Interpregnancy Interval and Risk of Preterm Birth and Its Modification by Folate Intake: The Japan Environment and Children's Study.

BACKGROUND: Both short and long interpregnancy intervals (IPIs) have been associated with risk of preterm birth, but the evidence is limited in Asians. It is also uncertain whether the association is modified by dietary folate intake or folic acid supplementation during pregnancy. Thus, we examined associations between IPI and risk of preterm birth and effect modification of those associations by dietary intake of folate and supplementation with folic acid on the basis of a nationwide birth cohort study. METHODS: Among 103,062 pregnancies registered in the Japan Environment and Children's Study, 55,203 singleton live-birth pregnancies were included in the analysis. We calculated IPI using birth date, gestational age at birth of offspring, and birth data of the latest offspring. Odds ratios (ORs) and 95% confidence intervals (CIs) of the risk of preterm birth were estimated according to IPI categories. RESULTS: Both <6-month and ≥120-month IPIs were associated with an increased risk of preterm birth, compared with an 18-23-month IPI. The multivariable ORs were 1.63 (95% CI, 1.30-2.04) for <6-month and 1.41 (95% CI, 1.11-1.79) for ≥120-month IPIs. These associations were confined to women with inadequate intake of dietary folate and folic acid supplementation during pregnancy. Multivariable ORs were 1.76 (95% CI, 1.35-2.29) for <6-month IPI and 1.65 (95% CI, 1.24-2.19) for ≥120-month IPI. CONCLUSION: Both <6-month and ≥120-month IPIs were associated with an increased risk of preterm birth. These higher risks were confined to women with inadequate intake of dietary folate and folic acid supplementation during pregnancy.

Risk and population attributable fraction of stroke subtypes in Japan.

BACKGROUND: Associations of major risk factors for stroke with total and each type of stroke as well as subtypes of ischemic stroke and their population attributable fractions had not been examined comprehensively. METHODS: Participants of the Japan Public Health Center-based prospective (JPHC) Study Cohort II without histories of cardiovascular disease and cancer (n=14,797) were followed from 1993 through 2012. Associations of current smoking, hypertension, diabetes, overweight (body mass index ≥ 25 kg/m2), non-high-density lipoprotein cholesterol (non-HDLC) categories, low HDLC (< 40 mg/dL), urine protein, and history of arrhythmia were examined in a mutually-adjusted Cox regression model that included age and sex. Population attributable fraction (PAF) was estimated using the hazard ratios and the prevalence of risk factors among cases. RESULTS: Subjects with hypertension were 1.63 to 1.84 times more likely to develop any type of stroke. Diabetes, low HDLC, current smoking, overweight, urine protein, and arrhythmia were associated with risk of overall and ischemic stroke. Hypertension and urine protein were associated with risk of intracerebral hemorrhage while current smoking, hypertension, and low non-HDLC were associated with subarachnoid hemorrhage. Hypertension alone accounted for more than a quarter of stroke incidence, followed by current smoking and diabetes. High non-HDLC, current smoking, low HDLC, and overweight contributed mostly to large-artery occlusive stroke. Arrhythmia explained 13.2% of embolic stroke. Combined PAFs of all the modifiable risk factors for total, ischemic and large-artery occlusive strokes were 36.7 and 44.5% and 61.5%, respectively. CONCLUSION: Although there are differences according to the subtypes, hypertension could be regarded as the most crucial target for preventing strokes in Japan.

Hobby Engagement and Risk of Disabling Dementia.

BACKGROUND: The association between hobby engagement and risk of dementia reported from a short-term follow-up study for individuals aged ≥65 years may be susceptible to reverse causation. We examined the association between hobby engagement in age of 40-69 years and risk of dementia in a long-term follow-up study among Japanese, including individuals in mid-life, when the majority of individuals have normal cognitive function. METHODS: A total of 22,377 individuals aged 40-69 years completed a self-administered questionnaire in 1993-1994. The participants answered whether they had hobbies according to the three following responses: having no hobbies, having a hobby, and having many hobbies. Follow-up for incident disabling dementia was conducted with long-term care insurance data from 2006 to 2016. RESULTS: During a median of 11.0 years of follow-up, 3,095 participants developed disabling dementia. Adjusting for the demographic, behavioral, and psychosocial factors, the multivariable hazard ratios of incident disabling dementia compared with "having no hobbies" were 0.82 (95% confidence interval [CI], 0.75-0.89) for "having a hobby" and 0.78 (95% CI, 0.67-0.91) for "having many hobbies". The inverse association was similarly observed in both middle (40-64 years) and older ages (65-69 years). For disabling dementia subtypes, hobby engagement was inversely associated with the risk of dementia without a history of stroke (probably non-vascular type dementia), but not with that of post-stroke dementia (probably vascular type dementia). CONCLUSION: Hobby engagement in both mid-life and late life was associated with a lower risk of disabling dementia without a history of stroke.

Association between birth weight and prevalence of cardiovascular disease and other lifestyle-related diseases among Japanese population: JPHC-NEXT Study.

BACKGROUND: An association between birth weight and cardiovascular disease (CVD) in adulthood has been observed in many countries; however, only a few studies have been conducted in Asian populations. METHODS: We used data from the baseline survey (2011-2016) of the Japan Public Health Center-based Prospective Study for the Next Generation Cohort, which included 114,105 participants aged 40-74 years. Adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs) were calculated from the prevalence of present and past histories of CVD and other lifestyle-related diseases, including hypertension, diabetes, hyperlipidemia, and gout, by birth weight, using Poisson regression. RESULTS: The prevalence of CVD increased with lower birth weight, with the highest prevalence among those with birth weight under 1,500 grams (males 4.6%; females 1.7%) and the lowest one among those with birth weight at or over 4,000g (males 3.7%: females 0.8%). Among 88.653 participants (41,156 males and 47,497 females) with complete data on possible confounders, birth weight under 1,500g was associated with a higher prevalence of CVD (aPR 1.76 [95%CI 1.37-2.26]), hypertension (aPR 1.29 [95%CI 1.17-1.42]), and diabetes (aPR 1.53 [95%CI 1.26-1.86]) when a birth weight of 3,000-3,999 grams was used as the reference. Weaker associations were observed for birth weight of 1500-2499 grams and 2500-2999 grams, while no significant associations were observed for birth weight at or over 4000 g. The association between birth weight and the prevalence of hyperlipidemia was less profound, and no significant association was observed between birth weight and gout. CONCLUSION: Lower birth weight was associated with a higher prevalence of CVD, hypertension, and diabetes in the Japanese population.