Kaori Ohmori

Prognostic significance of the nocturnal decline in blood pressure in individuals with and without high 24-h blood pressure: the Ohasama study.

Objective To examine the relationship between the normal nocturnal decline in blood pressure and the risk of cardiovascular mortality in individuals with and without high 24-h blood pressure values. Methods We obtained 24-h ambulatory blood pressure readings from 1542 residents of Ohasama, Japan, who were aged 40 years or more and were representative of the Japanese general population. We then followed up their survival for a mean of 9.2 years. The relationship was analysed using a Cox proportional hazards model adjusted for possible confounding factors. Results There was a linear relationship between the nocturnal decline in blood pressure and cardiovascular mortality. On average, each 5% decrease in the decline in nocturnal systolic/diastolic blood pressure was associated with an approximately 20% greater risk of cardiovascular mortality. There were no significant interactions for the risk between 24-h systolic/diastolic blood pressure values and continuous values for the nocturnal decline in blood pressure (P for interaction > 0.6). Even when 24-h blood pressure values were within the normal range (< 135/80 mmHg, average 118/69 mmHg), diminished nocturnal decreases in systolic/diastolic blood pressure were associated with an increased risk of cardiovascular mortality. Conclusions This is the first study to demonstrate that a diminished nocturnal decline in blood pressure is a risk factor for cardiovascular mortality, independent of the overall blood pressure load during a 24-h period, in the general population.

Obesity and risk of cancer in Japan

We conducted a population‐based prospective cohort study in Japan to examine the relationship between body mass index (BMI) and the risk of incidence of any cancer and of cancer at individual sites. Body mass index was calculated from self‐administered body weight and height at baseline. Relative risks (RR) and 95% confidence intervals (CI) were calculated in multivariate proportional‐hazards models. Among 27,539 persons (15,054 women and 12,485 men) aged 40 years or older who were free of cancer at enrollment in 1984, 1,672 (668 women and 1,004 men) developed cancer during 9 years of follow‐up. In women, after adjustment for potential confounders, the RR of all cancers associated with different BMI, relative to a BMI of 18.5–24.9, were 1.04 (95% CI = 0.85–1.27) for BMI = 25.0–27.4, 1.29 (1.00–1.68) for BMI = 27.5–29.9 and 1.47 (1.06–2.05) for BMI ≥30.0 (p for trend = 0.007). Higher BMI was also significantly associated with higher risk of cancers of the colorectum, breast (postmenopausal), endometrium and gallbladder in women. In men, we observed significantly increased all‐cancer risk among only never‐smokers. Overweight and obesity could account for 4.5% (all subjects) or 6.2% (never‐smokers) of the risk of any cancer in women and −0.2% (all subjects) or 3.7% (never‐smokers) in men. The value for women was within the range among women reported from Western populations (3.2%–8.8%). Our data demonstrate that excess weight is a major cancer risk among Japanese women.

Coffee consumption and the risk of primary liver cancer: Pooled analysis of two prospective studies in Japan

Although case‐control studies suggested that coffee consumption is associated with a decreased risk of liver cancer, no prospective cohort study has been carried out. To examine the association between coffee consumption and the risk of liver cancer, we conducted a pooled analysis of data available from 2 cohort studies in Japan. A self‐administered questionnaire about the frequency of coffee consumption and other health habits was distributed to 22,404 subjects (10,588 men and 11,816 women) in Cohort 1 and 38,703 subjects (18,869 men and 19,834 women) in Cohort 2, aged 40 years or more, with no previous history of cancer. We identified 70 and 47 cases of liver cancer among the subjects in Cohort 1 (9 years of follow‐up with 170,640 person‐years) and Cohort 2 (7 years of follow‐up with 284,948 person‐years), respectively. We used Cox proportional hazards regression analysis to estimate the relative risk (RR) and 95% confidence interval (CI) of liver cancer incidence. After adjustment for potential confounders, the pooled RR (95% CI) of drinking coffee never, occasionally and 1 or more cups/day were 1.00 (Reference), 0.71 (0.46–1.09) and 0.58 (0.36–0.96), respectively (p for trend = 0.024). In the subgroup of subjects with a history of liver disease, we found a significant inverse association between coffee consumption and the risk of liver cancer. Our findings support the hypothesis that coffee consumption decreases the risk of liver cancer. Further studies to investigate the role of coffee in prevention of liver cancer among the high‐risk population are needed.

Association between social support and depression status in the elderly: Results of a 1‐year community‐based prospective cohort study in Japan

Abstract  We conducted a prospective cohort study on subjects aged ≥ 70 years in an urban community to determine whether there is any association between lack of social support and depression status. Of the 2730 eligible subjects, 1178 participated and were interviewed in a Comprehensive Geriatric Assessment (CGA) in 2002. We investigated the five social supports items using the following questions: (i) do you have someone with whom you can consult when you are in trouble?, (ii) do you have someone with whom you can consult when your physical condition is not good?, (iii) do you have someone who can help you with your daily housework?, (iv) do you have someone who can take you to a hospital when you do not feel well?, and (v) do you have someone who can take care of you when you are ill in bed? The Geriatric Depression Scale was used to estimate depression status. The subjects were divided into two groups: depressive and non‐depressive. Of 753 subjects classified as non‐depressive, 475 also took part in a CGA in 2003 and 278 dropped out. We calculated the risk of depression status in the elderly without social support. Lack of social support items (i) and (v) were significantly associated with an increased risk of depression status. The multivariate odds ratios (95% confidence intervals) regarding the risk of depression status among the elderly without (i) and (v) social support items were 2.6 (1.2–5.3) and 3.0 (1.4–6.1), respectively. We also found the increase risk of depression status with lack of social support item (v) was significantly different for different sexes and for different pain conditions. We conclude that there is a significant increase in the risk of depression status associated with the lack of social support in Japanese elderly people in an urban community.

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.

Influence of leisure-time physical activity on the relationship between C-reactive protein and hypertension in a community-based elderly population of Japan : The tsurugaya project

There are several studies indicating an association between C-reactive protein (CRP) and blood pressure (BP) in the Japanese population, but the influence of physical activity has not been considered. Therefore, we designed a cross-sectional survey to determine whether leisure-time physical activity (LTPA) modifies the relation between CRP and hypertension among Japanese elderly. Our study population comprised 643 subjects aged 70 years and over in whom CRP, home BP, and self-reported LTPA were measured. LPTA was categorized into three levels of intensity—walking, brisk walking, and sports—and a questionnaire was used to estimate the level in each patient. Hypertension was defined as a home systolic BP of 135 mmHg or over and/or home diastolic BP of 85 mmHg or over or current use of antihypertensive agents. LTPA levels were associated with both CRP and hypertension. After adjustment for factors affecting CRP and hypertension, and additional adjustment for LTPA levels, the odds ratio (95% confidence interval) of hypertension by CRP was 2.21 (range: 1.33–3.72), 1.99 (1.17–3.42), and 2.38 (1.36–4.21) times higher in subjects in the second, third, and fourth quartiles of CRP, as compared to subjects in the first quartile, respectively. A multiple regression model showed a positive and significant relation between log-transformed CRP and systolic BP after adjustment for potential confounding factors when participants taking antihypertensive medication were excluded. This is the first study to clarify that the positive significant relation between CRP and hypertension was independent of LTPA levels among Japanese elderly.

Modifiable factors for the length of life with disability before death: Mortality retrospective study in Japan

Background: Past studies have measured and described the length of life with disability before death, but there has been no study of the relationship between modifiable lifestyle factors and duration of disability. Objective: To examine whether there are modifiable factors influencing the length of life with disability before death. Methods: The study was designed asa retrospective observation of the deceased who had earlier been enrolled in a prospective cohort study.During the follow-up period (1996–1999), we documented 781 deaths among those who were 70–79 years of age at the baseline survey in 1994 (n = 10,216). In 2000, we interviewed family members of the deceased about the duration of the subjects’ disability before death (n = 655). Results: The median duration of disability before death was approximately 6 months. Both higher Body Mass Index (BMI) and shorter time spent walking were significantly associated with an increased risk of long-term disability (more than 6 months). The odds ratios of long-term disability were 1.3 in those with BMI 20–25 and 2.1 in those with BMI >25, compared with BMI <20. The odds ratios of long-term disability were 1.3 in those walking for 0.5–0.9 h/day and 1.7 in those walking for <0.5 h/day, compared with those walking for >1.0 h/day. These relationships were unchanged after stratification for causes of death. Conclusion: Weight control and walking in later life may shorten the length of life with disability before death.

Dietary Intakes and Plasma 8-Iso-Prostaglandin F2α Concentrations in Community-Dwelling Elderly Japanese: The Tsurugaya Project

We examined the association between dietary intakes and oxidative stress status in elderly Japanese. We analyzed cross-sectional data from a community-based Comprehensive Geriatric Assessment conducted in 2002. The subjects included 961 Japanese subjects aged 70 years or older who were non-daily antioxidant supplements users. We measured plasma total 8-iso-prostaglandin (PG)F(2alpha) concentrations, a measurable lipid peroxidation biomarker, using a specific enzyme immunoassay kit. Dietary intakes were assessed through a food frequency questionnaire. Subjects were divided into three groups according to their dietary intake frequencies. Logistic regression was applied to calculate the odds ratios (ORs) for being in the highest tertile of plasma 8-iso-PGF(2alpha) concentration. Frequent intake of orange or other citrus fruits, or persimmon, strawberry, or kiwi fruit was associated with lower plasma 8-iso-PGF(2alpha) concentrations, respectively. After adjustment for potential confounders, the ORs and 95% confidence intervals (CIs) for orange or other citrus fruits were 1.00 (reference), 0.66 (0.47, 0.92), and 0.58 (0.39, 0.87) (p for trend, 0.009). Intake of persimmon, strawberry, or kiwi fruit showed similar results. These associations were partly explained by vitamin C intake. Other dietary intakes had no association. Intake of fruits may have a beneficial effect against oxidative stress in elderly Japanese.

Impact of Non-dietary Nutrients Intake on Misclassification in the Estimation of Nutrient Intake in Epidemiologic Study

BACKGROUND Few previous epidemiologic studies have evaluated the effects of non-dietary nutrient intake, such as supplements, over the counter (OTC) drugs, and prescription drugs containing vitamins or minerals, in examining the relationship between dietary factors and health outcomes. METHODS To examine the influence of the non-dietary intake of vitamins and calcium on the estimation of nutrient intake, we conducted a cross-sectional study with 1,168 community-dwelling Japanese subjects aged 70 years or older in 2002. The subjects were asked to bring their non-dietary nutrient sources to the examining site. The dietary and non-dietary intakes of vitamins B1, C, E and calcium were obtained and the subjects were grouped into quartiles according to their dietary intake and their dietary plus non-dietary intake. The degree of agreement between these two classifications was examined to estimate the degree of misclassification. RESULTS Among the subjects who were classified into the highest intake category for vitamin E with dietary intake plus non-dietary nutrient intake, 34.2 % were misclassified into lower category with dietary intake alone. Similarly, intake of vitamin B1, vitamin C and calcium were misclassified 28.8%, 18.8 %, 6.2 %, respectively. CONCLUSIONS Our data suggest that estimation of vitamin intake from dietary sources alone would yield a maximum misclassification of one-third, which would lead to misleading conclusions being drawn from epidemiologic studies. In contrast, the degree of misclassification for calcium may be relatively small.