Masako Kakizaki

Sleep duration and the risk of prostate cancer: the Ohsaki Cohort Study

In a prospective study of prostate cancer incidence (127 cases), among 22 320 Japanese men, sleep duration was associated with lower risk; the multivariate hazard ratio of men who slept ⩾9 h per day compared with those who slept less was 0.48 (95% confidence interval: 0.29–0.79, P for trend=0.02).

Association between body mass index and cardiovascular disease mortality in east Asians and south Asians: pooled analysis of prospective data from the Asia Cohort Consortium

Objective To evaluate the association between body mass index and mortality from overall cardiovascular disease and specific subtypes of cardiovascular disease in east and south Asians. Design Pooled analyses of 20 prospective cohorts in Asia, including data from 835 082 east Asians and 289 815 south Asians. Cohorts were identified through a systematic search of the literature in early 2008, followed by a survey that was sent to each cohort to assess data availability. Setting General populations in east Asia (China, Taiwan, Singapore, Japan, and Korea) and south Asia (India and Bangladesh). Participants 1 124 897 men and women (mean age 53.4 years at baseline). Main outcome measures Risk of death from overall cardiovascular disease, coronary heart disease, stroke, and (in east Asians only) stroke subtypes. Results 49 184 cardiovascular deaths (40 791 in east Asians and 8393 in south Asians) were identified during a mean follow-up of 9.7 years. East Asians with a body mass index of 25 or above had a raised risk of death from overall cardiovascular disease, compared with the reference range of body mass index (values 22.5-24.9; hazard ratio 1.09 (95% confidence interval 1.03 to 1.15), 1.27 (1.20 to 1.35), 1.59 (1.43 to 1.76), 1.74 (1.47 to 2.06), and 1.97 (1.44 to 2.71) for body mass index ranges 25.0-27.4, 27.5-29.9, 30.0-32.4, 32.5-34.9, and 35.0-50.0, respectively). This association was similar for risk of death from coronary heart disease and ischaemic stroke; for haemorrhagic stroke, the risk of death was higher at body mass index values of 27.5 and above. Elevated risk of death from cardiovascular disease was also observed at lower categories of body mass index (hazard ratio 1.19 (95% confidence interval 1.02 to 1.39) and 2.16 (1.37 to 3.40) for body mass index ranges 15.0-17.4 and <15.0, respectively), compared with the reference range. In south Asians, the association between body mass index and mortality from cardiovascular disease was less pronounced than that in east Asians. South Asians had an increased risk of death observed for coronary heart disease only in individuals with a body mass index greater than 35 (hazard ratio 1.90, 95% confidence interval 1.15 to 3.12). Conclusions Body mass index shows a U shaped association with death from overall cardiovascular disease among east Asians: increased risk of death from cardiovascular disease is observed at lower and higher ranges of body mass index. A high body mass index is a risk factor for mortality from overall cardiovascular disease and for specific diseases, including coronary heart disease, ischaemic stroke, and haemorrhagic stroke in east Asians. Higher body mass index is a weak risk factor for mortality from cardiovascular disease in south Asians.

Coffee Consumption and Mortality Due to All Causes, Cardiovascular Disease, and Cancer in Japanese Women

Coffee contains various compounds that have recently been reported to exert beneficial health effects. However, the conclusion of its relation with mortality has not yet been reached. In this study, we aimed to investigate the associations between coffee consumption and all-cause and cause-specific mortality in Japan. We included 37,742 participants (18,287 men and 19,455 women) aged 40-64 y without a history of cancer, myocardial infarction, or stroke at baseline in our analysis, based on the Miyagi Cohort Study initiated in 1990. The outcomes were mortality due to all causes, cardiovascular disease (CVD), and cancer. During the 10.3 y of follow-up, 2454 participants died, including 426 due to CVD and 724 due to cancer. In women, the multivariate hazard ratios (HR) (95% CI) for all-cause mortality in participants who drank coffee never, occasionally, 1-2 cups (150-300 mL)/d, and > or =3 cups/d were 1.00, 0.88 (0.73-1.06), 0.82 (0.66-1.02), and 0.75 (0.53-1.05), respectively (P-trend = 0.04). For CVD mortality in women, the multivariate HR (95% CI) were 1.00, 0.56 (0.36-0.86), 0.48 (0.29-0.80), and 0.45 (0.20-1.03), respectively (P-trend = 0.006). Of the specific CVD diseases, there was a strong inverse association between coffee consumption and mortality due to coronary heart disease (CHD) in women (P-trend = 0.02) but not in men. Death due to cancer was not associated with coffee consumption in either men or women, except for colorectal cancer in women. Our results suggest that coffee may have favorable effects on morality due to all causes and to CVD, especially CHD, in women.

Sense of Life Worth Living (Ikigai) and Mortality in Japan : Ohsaki Study

Objective: To investigate the association between the sense of “life worth living (ikigai)” and the cause-specific mortality risk. The psychological factors play important roles in morbidity and mortality risks. However, the association between the negative psychological factors and the risk of mortality is inconclusive. Methods: The Ohsaki Study, a prospective cohort study, was initiated on 43,391 Japanese adults. To assess if the subjects found a sense of ikigai, they were asked the question, “Do you have ikigai in your life?” We used Cox regression analysis to calculate the hazard ratio of the all-cause and cause-specific mortality according to the sense of ikigai categories. Results: Over 7 years’ follow-up, 3048 of the subjects died. The risk of all-cause mortality was significantly higher among the subjects who did not find a sense of ikigai as compared with that in the subjects who found a sense of ikigai; the multivariate adjusted hazard ratio (95% confidence interval) was 1.5 (1.3–1.7). As for the cause-specific mortality, subjects who did not find a sense of ikigai were significantly associated with an increased risk of cardiovascular disease (1.6; 1.3–2.0) and external cause mortality (1.9; 1.1–3.3), but not of the cancer mortality (1.3; 1.0–1.6). Conclusions: In this prospective cohort study, subjects who did not find a sense of ikigai were associated with an increased risk of all-cause mortality. The increase in mortality risk was attributable to cardiovascular disease and external causes, but not cancer. CVD = cardiovascular disease; NHI = National Health Insurance; PHC = Public Health Center; IHD = ischemic heart disease; HR = hazard ratio; CI = confidence interval; BMI = body mass index.

Meat intake and cause-specific mortality: a pooled analysis of Asian prospective cohort studies

BACKGROUND Total or red meat intake has been shown to be associated with a higher risk of mortality in Western populations, but little is known of the risks in Asian populations. OBJECTIVE We examined temporal trends in meat consumption and associations between meat intake and all-cause and cause-specific mortality in Asia. DESIGN We used ecological data from the United Nations to compare country-specific meat consumption. Separately, 8 Asian prospective cohort studies in Bangladesh, China, Japan, Korea, and Taiwan consisting of 112,310 men and 184,411 women were followed for 6.6 to 15.6 y with 24,283 all-cause, 9558 cancer, and 6373 cardiovascular disease (CVD) deaths. We estimated the study-specific HRs and 95% CIs by using a Cox regression model and pooled them by using a random-effects model. RESULTS Red meat consumption was substantially lower in the Asian countries than in the United States. Fish and seafood consumption was higher in Japan and Korea than in the United States. Our pooled analysis found no association between intake of total meat (red meat, poultry, and fish/seafood) and risks of all-cause, CVD, or cancer mortality among men and women; HRs (95% CIs) for all-cause mortality from a comparison of the highest with the lowest quartile were 1.02 (0.91, 1.15) in men and 0.93 (0.86, 1.01) in women. CONCLUSIONS Ecological data indicate an increase in meat intake in Asian countries; however, our pooled analysis did not provide evidence of a higher risk of mortality for total meat intake and provided evidence of an inverse association with red meat, poultry, and fish/seafood. Red meat intake was inversely associated with CVD mortality in men and with cancer mortality in women in Asian countries.

Adiposity, adult weight change and breast cancer risk in postmenopausal Japanese women: the Miyagi Cohort Study.

Background:The role of adult weight change in breast cancer (BC) risk is unclear in Japanese women.Methods:A total of 10 106 postmenopausal women aged 40–64 years (the Miyagi Cohort) were followed from 1990 to 2003, and 108 BC cases were identified. Hazard ratios (HRs) were estimated according to body mass index (BMI) at the current age and at the of age 20 years, and weight change since age 20 years.Results:Higher current BMI was associated with an increased risk of BC (P for trend=0.02), whereas higher BMI at the age 20 years was inversely associated with this risk (P for trend=0.002). There was a significant association between weight change since age 20 years and BC risk (P for trend=0.0086). Compared with stable weight, HR was 0.35 for weight loss of 5 kg or more (P for weight loss trend=0.04) and 1.55 for weight gain of 12 kg or more (P for weight gain trend=0.05).Conclusion:Adiposity at younger and current age has differential effects on BC risk among postmenopausal women; weight gain in adulthood being associated with an increased, and weight loss with a decreased risk.

Coffee Consumption and the Risk of Oral, Pharyngeal, and Esophageal Cancers in Japan The Miyagi Cohort Study

An inverse association between coffee consumption and the risk of oral, pharyngeal, and esophageal cancers has been suggested in case-control studies, but few results from prospective studies are available. Data from the Miyagi Cohort Study in Japan were used to clarify the association between coffee consumption and the risk of these cancers. Information about coffee consumption was obtained from self-administered food frequency questionnaires in 1990. Among 38,679 subjects aged 40-64 years with no previous history of cancer, 157 cases of oral, pharyngeal, and esophageal cancers were identified during 13.6 years of follow-up. Hazard ratios were estimated by the Cox proportional hazards regression model. The risk of oral, pharyngeal, and esophageal cancers was inversely associated with coffee consumption. The multivariate-adjusted hazard ratio of these cancers for > or =1 cups of coffee per day compared with no consumption was 0.51 (95% confidence interval: 0.33, 0.77). This inverse association was consistent regardless of sex and cancer site and was observed both for subjects who did not drink or smoke and for those who currently drank or smoked at baseline. In conclusion, coffee consumption was associated with a lower risk of oral, pharyngeal, and esophageal cancers, even in the group at high risk of these cancers.

Green tea consumption and the risk of incident functional disability in elderly Japanese: the Ohsaki Cohort 2006 Study

Background: Previous studies have reported that green tea consumption is associated with a lower risk of diseases that cause functional disability, such as stroke, cognitive impairment, and osteoporosis. Although it is expected that green tea consumption would lower the risk of incident functional disability, this has never been investigated directly. Objective: The objective was to determine the association between green tea consumption and incident functional disability in elderly individuals. Design: We conducted a prospective cohort study in 13,988 Japanese individuals aged ≥65 y. Information on daily green tea consumption and other lifestyle factors was collected via questionnaire in 2006. Data on functional disability were retrieved from the public Long-term Care Insurance database, in which subjects were followed up for 3 y. We used Cox proportional hazards regression analysis to investigate the association between green tea consumption and functional disability. Results: The 3-y incidence of functional disability was 9.4% (1316 cases). The multiple-adjusted HR (95% CI) of incident functional disability was 0.90 (0.77, 1.06) among respondents who consumed 1–2 cups green tea/d, 0.75 (0.64, 0.88) for those who consumed 3–4 cups/d, and 0.67 (0.57, 0.79) for those who consumed ≥5 cups/d in comparison with those who consumed <1 cup/d (P-trend < 0.001). Conclusion: Green tea consumption is significantly associated with a lower risk of incident functional disability, even after adjustment for possible confounding factors.

Factors Associated With Psychological Distress in a Community-Dwelling Japanese Population: The Ohsaki Cohort 2006 Study

Background In Asia, there has been no population-based epidemiological study using the K6, a 6-item instrument that assesses nonspecific psychological distress. Methods Using cross-sectional data from 2006, we studied 43 716 (20 168 men and 23 548 women) community-dwelling people aged 40 years or older living in Japan. We examined the association between psychological distress and demographic, medical, lifestyle, and social factors by using the K6, with psychological distress defined as 13 or more points out of a total of 24 points. Results The following variables were significantly associated with psychological distress among the population: female sex, young and old age, a history of serious disease (hypertension, diabetes mellitus, stroke, myocardial infarction, or cancer), current smoking, former alcohol drinking, low body mass index, shorter daily walking time, lack of social support (4 of 5 components), and lack of participation in community activities (4 of 5 components). Among men aged 40 to 64 years, only “lack of social support for consultation when in trouble” and a history of diabetes mellitus remained significant on multivariate analysis. Among men aged 65 years or older, age was not significantly associated with psychological distress, and the significant association with current smoking disappeared on multivariate analysis. Among women aged 40 to 64 years, a history of stroke was not associated with psychological distress. Among women aged 65 years or older, the significant association with current smoking disappeared on multivariate analysis. Conclusions A number of factors were significantly associated with psychological distress, as assessed by the K6. These factors differed between men and women, and also between middle-aged and elderly people.

Long sleep duration and cause-specific mortality according to physical function and self-rated health: the Ohsaki Cohort Study

Although several studies have examined the association between sleep duration and all‐cause or cause‐specific mortality, it is unclear whether long sleep duration might merely reflect decreased physical strength and poorer health status. We therefore examined the association between sleep duration and all‐cause and cause‐specific mortality, and conducted stratified analysis based on physical function and self‐rated health. This study used prospective data from the Ohsaki Cohort Study, conducted in Miyagi Prefecture, in northern Japan. This study population comprised 49 256 subjects aged 40–79 years at the baseline survey. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) of all‐cause and cause‐specific mortality according to the five categories of sleep duration (≤6, 7, 8, 9, ≥10 h day−1), treating 7 h as the reference group, employing Coxs proportional hazard regression analysis. We found that long sleep duration was associated with mortality. The HRs (95% CIs) of subjects who slept more than 10 h were 1.37 (1.27–1.47), 1.49 (1.30–1.71) and 1.53 (1.36–1.73) for mortality due to all causes, total cardiovascular disease and other causes of death mortality, respectively. The association between long sleep duration and stroke mortality was especially marked among subjects with limited physical function and poorer health status. However, we did not observe such a trend for mortality due to all causes, total cardiovascular disease, ischaemic heart disease, cancer or other causes of death. We conclude that, with the exception of stroke mortality, the association between long sleep duration and mortality is not modified by physical function or health status.