Japan Public Health Center-based Study Research Articles

Perceived Level of Life Enjoyment and Risk of Developing Disabling Dementia: The Japan Public Health Center-Based Study.

Life enjoyment, linked to the ability to engage pleasurably with one's environment, may be related to the risk of developing dementia. This prospective cohort study examined the association between level of life enjoyment and disabling dementia incidence among Japanese community residents. The participants were Japanese, aged 45-74 years old at 5-years follow-up, in the Japan Public Health Center-based Study (N = 38,660). Psychological conditions and other confounding variables were identified through self-administered questionnaires. Incident disabling dementia registered based on the Japan's Long-Term Care Insurance system from 2006 to 2016. Hazard ratios [95% confidence intervals] were assessed using Cox proportional hazards models. Over a median follow-up period of 9.4 years, a total of 4,642 cases of disabling dementia developed. Level of life enjoyment was inversely associated with the risk of disabling dementia: the multivariable hazard ratios were 0.75 [0.67-0.84] (p < .001) and 0.68 [0.59-0.78] (p < .001) with medium and high life enjoyment, respectively, compared to low life enjoyment. Furthermore, the association between greater life enjoyment and low risk for disabling dementia was strongest in the subgroup with low-medium mental stress. In the high mental stress group, this association was evident for poststroke disabling dementia, but not for disabling dementia without a history of stroke. A higher level of life enjoyment was associated with a lower risk of disabling dementia, particularly in the low-medium mental stress group. This finding suggests the importance of having life enjoyment by managing mental stress for reducing risk of disabling dementia.

Having hobbies and the risk of cardiovascular disease incidence: A Japan public health center-based study

Background and aimsThe role of hobbies as a protective factor against cardiovascular diseases (CVD) has gained increasing attention; however, no large-scale studies were performed to confirm this. We aimed to examine the association between having hobbies and the risk of total CVD, coronary heart disease (CHD), and stroke in a large Japanese cohort. MethodsA total of 56,381 adults aged 40–69 years were divided into the non-hobby, having a hobby, and having many hobbies groups. We performed Cox proportional hazard models to estimate the hazard ratio (HRs) for incident CVD, CHD, and stroke after adjusting for potential confounding factors. ResultsWe identified 3685 incident CVDs (940 CHDs and 2839 strokes) during a median follow-up of 16.3 years. After multivariable adjustment, compared to the non-hobby group, participants having a hobby and many hobbies had a 10% (HR = 0.90 [0.83, 0.97]) and 20% (HR = 0.80 [0.69, 0.93]) lower risk of CVD incidence, respectively. The risk of CHD was lower in those with many hobbies, but the association between having many hobbies and CHD risk was not statistically significant. We also found a similar inverse association for stroke. Compared to the non-hobby group, participants having a hobby and many hobbies had a 13% (HR = 0.87 [0.80, 0.96]) and 20% (HR = 0.80 [0.68, 0.94]) lower risk of stroke. ConclusionsHaving hobbies was associated with a lower risk of CVD. Engagement in hobbies may emerge as an important target for healthy lifestyle promotion for the primary prevention of CVD.

Coping strategies and cancer incidence and mortality: The Japan Public Health Center-based prospective study

BackgroundPsychological stress is a modifiable risk factor for health outcomes and can be managed through coping mechanisms. Biological and behavioral hypotheses have been proposed to explain the association between stress coping strategies and cancer outcomes. MethodsThe Japan Public Health Center-based study asked questions on coping behaviors in its 10-year follow-up survey. 55,130 subjects aged 50–79 without a history of cancer diagnosis and who provided complete answers on coping were included in analyses on cancer incidence and mortality. Hazard Ratios (HR) according to coping style were determined using Cox regression models adjusted for known confounders for cancer. ResultsMean follow-up time was 9.5 years for cancer incidence and 9.8 years for cancer mortality. The utilization of the approach-oriented coping strategy (HR=0.85, 95% CI: 0.72–0.99) and a behavior of positive reappraisal (HR=0.84, 95% CI: 0.72–0.97) was associated with a reduced risk of cancer mortality. The approach-oriented coping strategy was further associated with localized cancer incidence (HR=1.13, 95% CI: 1.01–1.27) and screening-detected cancers (HR=1.35, 95% CI: 1.15–1.58). The avoidance oriented coping strategy was inversely associated with cancer incidence (HR=0.69, 95% CI: 0.50–0.94) only after excluding events occurring in the first three years of follow-up. ConclusionThe results of this study may favor the behavioral hypothesis to explain associations between premorbid coping styles and cancer outcomes.

The association of active and secondhand smoking with oral health in adults: Japan public health center-based study.

BackgroundSmoking is one of the major risk factors for oral diseases, and many studies have found that active smoking is closely associated with the prevalence or severity of periodontal disease and fewer remaining teeth. In contrast to the established association between active smoking and oral health, there have been very few studies investigating the effects of secondhand smoking on oral health, and whether secondhand smoking deteriorates oral health has not been fully clarified. The purpose of the present study was to examine whether active and secondhand smoking were associated with the prevalence of severe periodontal disease and number of teeth among Japanese adults.MethodsSubjects were 1,164 dentate adults aged 55–75 years as of May 2005 who participated in both the Japan Public Health Center-Based Study Cohort I in 1990 and a dental survey in 2005. The dental survey was implemented in the Yokote health center jurisdiction, Akita Prefecture. Participating subjects completed a self-administered questionnaire and a clinical oral examination. The association of smoking status with prevalence of periodontal disease was analyzed using a logistic regression, and with number of teeth or functional tooth units of natural teeth (n-FTUs) using a generalized linear model.ResultsAfter adjusting for age, education level, history of diabetes, BMI, alcohol consumption, perceived mental stress, presence of a family dentist, and oral hygiene, the odds ratio (OR) of risk for periodontal disease in male subjects was significantly increased in non-smokers with secondhand smoking only at home (OR = 3.14, 95 % CI: 1.08−9.12, p = 0.036), non-smokers with secondhand smoking both at home and other places (OR = 3.61, 95 % CI: 1.33−9.81, p = 0.012) and current smokers (OR = 3.31, 95 % CI: 1.54−7.08, p = 0.002), compared to non-smokers without secondhand smoking. Further in men, current smokers had significantly fewer numbers of teeth (19.7 ± 6.82) and n-FTUs (4.92 ± 4.12) than non-smokers without secondhand smoking (22.2 ± 6.92, p = 0.014 and 6.56 ± 4.18, p = 0.007). Such significant relationships of smoking status with periodontal disease and dentition were not observed in women.ConclusionsThe present study indicates that active smoking as well as secondhand smoking may have harmful effects on periodontal health in men. Therefore, it is imperative for health and oral health professionals to enlighten people about the negative influence of smoking, not only on their own health but also on others’ health.

Association between parity and dentition status among Japanese women: Japan public health center-based oral health study.

BackgroundSeveral studies have shown that parity is associated with oral health problems such as tooth loss and dental caries. In Japan, however, no studies have examined the association. The purpose of this study was to determine whether parity is related to dentition status, including the number of teeth present, dental caries and filled teeth, and the posterior occlusion, in a Japanese population by comparing women with men.MethodsA total of 1,211 subjects, who participated both in the Japan Public Health Center-Based (JPHC) Study Cohort I in 1990 and the dental survey in 2005, were used for the study. Information on parity or number of children was collected from a self-completed questionnaire administered in 1990 for the JPHC Study Cohort I, and health behaviors and clinical dentition status were obtained from the dental survey in 2005. The association between parity or number of children and dentition status was analyzed, by both unadjusted-for and adjusted-for socio-demographic and health behavioral factors, using a generalized linear regression model.ResultsParity is significantly related to the number of teeth present and n-FTUs (Functional Tooth Units of natural teeth), regardless of socio-demographic and health behavioral factors, in female subjects. The values of these variables had a significantly decreasing trend with the rise of parity: numbers of teeth present (p for trend = 0.046) and n-FTUs (p for trend = 0.026). No relationships between the number of children and dentition status were found in male subjects.ConclusionHigher-parity women are more likely to lose teeth, especially posterior occluding relations. These results suggest that measures to narrow the discrepancy by parity should be taken for promoting women’s oral health. Delivery of appropriate information and messages to pregnant women as well as enlightenment of oral health professionals about dental management of pregnant women may be an effective strategy.

The combination of Helicobacter pylori- and cytotoxin-associated gene-A seropositivity in relation to the risk of myocardial infarction in middle-aged Japanese: The Japan Public Health Center-based study

BackgroundLimited evidence is available concerning the impact of the combination of Helicobacter pylori- (H. pylori) and cytotoxin-associated gene-A (CagA)-positivity on the risk of myocardial infarction (MI) and stroke, particularly in Asian populations, in which the prevalence of H. pylori infection is high. MethodsA prospective, nested case–control study was conducted to examine the association between H. pylori and CagA and risk of MI and stroke within a cohort of 29,876 men and women aged 40–69 years with no history of heart disease, stroke or cancer. Participants completed a risk factor survey and donated blood samples between 1990 and 1994. Systematic cardiovascular surveillance was performed through 2002. One control for each stroke case and two controls for each MI case were matched by sex, age, date of blood sampling, time since last meal and study location. ResultsDuring the follow-up period, there were 600 strokes and 106 MIs. H. pylori-IgG positivity was not associated with the risk of MI, while CagA positivity tended to be associated with it (OR = 1.72, 95%CI: 0.91–3.26, p = 0.10). We found no association between H. pylori or CagA and risk of stroke. ConclusionsH. pylori infection was not significantly associated with risk of MI and stroke among middle-aged Japanese. However, CagA positivity tended to be associated with MI.

Response to Letter Regarding Article, “The Impact of Green Tea and Coffee Consumption on the Reduced Risk of Stroke Incidence in Japanese Population: The Japan Public Health Center-Based Study Cohort”

Response: We thank Dr Chen for his interest in our article and his valuable suggestions on this topic. As you know, in our study, we found that higher green tea drinking (≥2 cups/d) or coffee consumption (≥1 cup/d) was inversely associated with the risk of cardiovascular disease and stroke, especially of intracerebral hemorrhage.1 In a further analysis, we found significant decreases in the incidence of stroke among participants who drank green tea (multivariable-adjusted hazard ratio [HR], 0.88; 95% confidence intervals [CIs], 0.81–0.95) or coffee (HR, 0.88; 95% CIs, 0.82–0.94) as a whole (≥1 cup/wk) compared with nondrinkers. In addition, the participants who drank green tea ≥4 cups/d (HR, 0.86; 95% …

Letter by Chen Regarding Article, “The Impact of Green Tea and Coffee Consumption on the Reduced Risk of Stroke Incidence in Japanese Population: The Japan Public Health Center-Based Study Cohort”

To the Editor: In a recent study published in Stroke , Kokubo et al1 reported that consumption of green tea and coffee could significantly reduce the risk of stroke; compared with no tea drinking, participants drinking ≥4 cups/d had a 20% reduction in incidence of all strokes, and a similar reduction was found for those drinking coffee ≥2 cups/d compared with no coffee drinking. It would be interesting to see whether or not there were any significant differences in incidence of stroke between participants with drinking tea or coffee as a whole and those that are nondrinkers. The large data from the Japan Public Health Center (JPHC)–Based …

The Impact of C-Reactive Protein on Risk of Stroke, Stroke Subtypes, and Ischemic Heart Disease in Middle-Aged Japanese: the Japan Public Health Center-Based Study

To examine the impact of C-reactive protein on the risks of stroke and its subtypes, particularly among Asian populations in which median C-reactive protein levels are typically lower than in Western populations. A prospective, nested case-control study was conducted to examine the associations between high sensitivity-CRP (hs-CRP) and risks of cardiovascular disease within a cohort of 29,876 men and women aged 40-69 years, with no history of stroke, ischemic heart disease or cancer, who submitted blood samples between 1990 and 1993. Systematic cardiovascular surveillance was performed throughout 2007. One control for each stroke and two controls for each ischemic heart disease were matched for sex, age, date of blood drawing, time since last meal and study location. We documented 1,132 incident strokes (638 ischemic and 494 hemorrhagic strokes) and 209 ischemic heart diseases (168 myocardial infarctions and 41 sudden cardiac deaths), and observed a linear association between hs-CRP levels and risks of ischemic stroke and ischemic heart disease, more specifically myocardial infarction. The multivariable odds ratios associated with 1-SD increment of logarithmically transformed hs-CRP were 1.13 (0.99-1.29),p= 0.07 for ischemic stroke, 1.16 (0.96-1.41),p= 0.13 for lacunar infarction, 1.41 (0.98-2.01),p= 0.06 for embolic infarction, and 1.28 (1.03-1.59),p= 0.03 for myocardial infarction. The predictive value of hs-CRP for ischemic stroke was reduced primarily after adjustment for hypertensive status and body mass index. No association was found between hs-CRP levels and the risk of hemorrhagic or total stroke. High serum hs-CRP levels were associated with the risk of myocardial infarction and more weakly with the risk of ischemic stroke among middle-aged Japanese men and women.

Dietary fiber intake and risk of cardiovascular disease in the Japanese population: the Japan Public Health Center-based study cohort

There has been no study with regard to the association between dietary fibers and the incidence of stroke and coronary heart disease (CHD) in Asia. We investigated the association between dietary fiber and the risk of cardiovascular disease (CVD), which we defined as stroke or CHD, in a Japanese population. We studied 86 387 Japanese subjects (age 45-65 years, without CVD or cancer in 1995 as Cohort I and in 1998 as Cohort II) and used a self-administered questionnaire to follow-up the participants until the end of 2004. Dietary fiber intake was estimated from food-frequency questionnaires comprising 138 food items. After 899 141 person-years of follow-up, we documented the incidence of 2553 strokes and 684 cases of CHD. Multivariable-adjusted hazard ratios (95% confidence intervals (CIs)) of CVD for the third to fifth quintiles of total fiber were 0.79 (0.63-0.99), 0.70 (0.54-0.89) and 0.65 (0.48-0.87) in women, respectively, compared with the lowest quintile. Total fiber intake was inversely associated with the incidence of stroke, either cerebral infarction or intracerebral hemorrhage in women. The results for insoluble fiber in women were similar to those for total fiber, whereas those for soluble fiber were weak. An inverse association of total fiber with CVD was observed primarily in non-smokers (P for trend=0.045 and 0.001) and not in smokers (probability values for interaction between total fiber and smoking were 0.06 and 0.01 in men and women, respectively). Higher total dietary fiber was associated with reduced risk of CVD in Japanese non-smokers.

Long chain n-3 fatty acids intake, fish consumption and suicide in a cohort of Japanese men and women — The Japan Public Health Center-based (JPHC) Prospective Study

Objective Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been implicated as protective against suicide. However, it is uncertain whether a higher intake of EPA and DHA or of fish, a major source of these nutrients, lowers suicidal risk among Japanese, whose fish consumption and suicide rate are both high. This study prospectively examined the relation between fish, EPA, or DHA intake and suicide among Japanese men and women. Method Subjects were 47,351 men and 54,156 women aged 40–69 years who participated in the JPHC Study, completed a food frequency questionnaire in 1995–1999, and were followed for death through December 2005. We used the Cox proportional hazards regression model to estimate the hazard ratio (HR) and 95% confidence interval (CI) for suicide by quintile of intake. Results A total of 213 and 85 deaths from suicide were recorded during 403,019 and 473,351 person-years of follow-up for men and women, respectively. Higher intakes of fish, EPA, or DHA were not associated with a lower risk of suicide. Multivariate HRs (95% CI) of suicide death for the highest versus lowest quintile of fish consumption were 0.95 (0.60–1.49) and 1.20 (0.58–2.47) for men and women, respectively. A significantly increased risk of suicidal death was observed among women with very low intake of fish, with HRs (95% CI) for those in 0–5th percentile versus middle quintile of 3.41 (1.36–8.51). Conclusions Our overall result does not support a protective role of higher intake of fish, EPA, or DHA against suicide in Japanese men and women.

10-Year risk of colorectal cancer: Development and validation of a prediction model in middle-aged Japanese men

Background: To estimate an individual's probability of developing colorectal cancer (CRC) may aid health professionals and individuals in improving lifestyle behaviors or deciding the screening regimens. As fewer studies on cancer risk prediction were seen so far, we initially developed an assessment tool with synthesizing key information from a variety of CRC risk factors through a large population-based cohort study. Method: The prediction model was derived from 28,115 men in the Japan Public Health Center-based (JPHC) Prospective Study Cohort II (follow-up: 1993–2005), with risk factors selected by Cox proportion hazard regression. 18,256 men in the JPHC Study Cohort I (follow-up: 1995–2005) were used to evaluate the model's performance. Results: 543 and 398 CRCs were diagnosed during the follow-up period in Cohorts II and I, respectively. The prediction model, including age, BMI, alcohol consumption, smoking status, and the daily physical activity level, showed modest discrimination ability for CRC ( C = 0.70; 95% confidential interval, 0.68–0.72) in Cohort II and well calibrated in Cohort I (Hosmer–Lemeshow χ 2 = 14.2, P = 0.08). Conclusion: The 10-year CRC risk prediction model may be used to estimate CRC risk in Japanese men. It may also play a role in the promotion of CRC prevention strategies.

The impact of the metabolic syndrome and its components on the incidence of ischemic heart disease and stroke: the Japan public health center-based study

In this study, we aimed to examine the impact of the metabolic syndrome and its components on the risk of cardiovascular disease among a relatively less-obese population. A total of 8249 men and 15 064 women, aged 40-69 years, with no history of ischemic heart disease, stroke and/or cancer completed a risk-factor survey between 1993 and 1995. The metabolic syndrome was defined based on modified criteria of the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) and the International Diabetes Federation (IDF). Systematic cardiovascular surveillance was carried out throughout 2003, and 693 events of ischemic heart disease and stroke were identified. We observed significant associations of the metabolic syndrome with the risk of ischemic heart disease and ischemic stroke, but not with hemorrhagic stroke. The multivariable hazard ratio (95% confidence interval) of ischemic heart disease among men for the metabolic syndrome based on the AHA/NHLBI criteria was 2.25 (1.44-3.51) and that of ischemic stroke was 1.88 (1.40-2.52). The respective hazard ratios for the metabolic syndrome based on the IDF criteria were 1.61 (0.99-2.64) for ischemic heart disease and 1.94 (1.41-2.68) for ischemic stroke. The population-attributable fraction (PAF) of the metabolic syndrome based on the AHA/NHLBI criteria was higher than that based on the IDF criteria: 19 vs. 12% (P for difference=0.003) for ischemic cardiovascular disease among men, because non-overweight men with >or=2 risk factors were also at high risk (20% of the PAF). Our data suggest that the metabolic syndrome based on the AHA/NHLBI criteria predicts ischemic cardiovascular disease better than the syndrome based on the IDF criteria, because of the exclusion of non-overweight high-risk individuals from the reference group.

Body mass index and weight change since 20 years of age and risk of coronary heart disease among Japanese: the Japan Public Health Center-Based Study

Obesity and weight gain are associated with increased risk of coronary heart disease in Western countries. However, their impact is not well elucidated in Asia, where body mass index (BMI) levels are generally lower than in Western countries. We examined associations of BMI (kg/m(2)) and weight change with risk of coronary heart disease in Japanese people. A total of 43 235 men and 47 444 women aged 40-69 years living in communities were followed up from 1990 to 2001 in the Japan Public Health Center-based (JPHC) prospective study . During 879 619 person-years of follow-up, we documented 399 cases of coronary heart disease (334 myocardial infarction and 65 sudden cardiac death) for men and 119 (95 myocardial infarction and 24 sudden cardiac death) for women. Compared with persons with BMI 23.0-24.9, men, but not women, with BMI >/=30.0 had higher risk of coronary heart disease and myocardial infarction; the multivariable relative risks for men were 1.8 (1.1-3.0) and 1.9 (1.1-3.2), respectively. When weight change was examined according to BMI at age 20 years, men with initial BMI <21.7 who gained more than 10 kg compared with men of no weight change had a twofold higher risk of coronary heart disease. Both men and women with initial BMI >/=21.7 showed no association between weight loss and the risk. High BMI was associated with increased risk of coronary heart disease among men. Also, weight gain was associated with increased risk among lean men.