The Ohsaki Cohort 2006 Study: design of study and profile of participants at baseline.

BACKGROUND: Large-scale cohort studies conducted in Japan do not always include psychosocial factors as exposures. In addition, such studies sometimes fail to satisfactorily evaluate disability status as an outcome. METHODS: This prospective cohort study comprised 49 603 (22 438 men and 27 165 women) community-dwelling adults aged 40 years or older who were included in the Residential Registry for Ohsaki City, Miyagi Prefecture, in northeastern Japan. The baseline survey, which included psychosocial factors, was conducted in December 2006. Follow-up of death, immigration, cause of death, cancer incidence, and long-term care insurance certification was started on 1 January 2007. RESULTS: The response rate was 64.2%. In general, lifestyle-related conditions in the study population were similar to those of the general Japanese population; however, the proportion of male current smokers was higher in the cohort. The association between age and the proportion of those reporting psychological distress showed a clear U-shaped curve, with a nadir at age 60 to 69 years in both men and women, although more women were affected by such distress than men. The proportion of those who reported a lack of social support was highest among those aged 40 to 49 years. Most men and women surveyed did not participate in community activities. Among participants aged 65 years or older, 10.9% of participants were certified beneficiaries of the long-term care insurance system at baseline. CONCLUSIONS: The Ohsaki Cohort 2006 Study is a novel population-based prospective cohort study that focuses on psychosocial factors and long-term care insurance certification.

Calcium intake and associated factors in a general Japanese population: baseline data of NIPPON DATA80/90 and the National Nutrition Survey.

OBJECTIVE: The purpose of this study was to investigate the dietary calcium intake and associated other dietary factors among representative sample of Japanese general men and women. METHODS: Data was obtained by linking NIPPON DATA80 and 90 with the corresponding National Nutrition Surveys held in 1980 and 1990. We analyzed data for 10,422 subjects (4585 men and 5837 women) in NIPPON DATA80 and 8342 subjects (3488 men and 4854 women) in NIPPON DATA90. Calcium intake was calculated by age groups. Dietary calcium intake was classified into quintiles and physical, life-style, and dietary parameters were examined across the quintiles. RESULTS: For both men and women, calcium intake tended to be positively associated with age in NIPPON DATA80 and 90, and there were significant differences in estimated calcium intake between age groups. Calcium intake tended to be positively associated with age, protein, fat, saturated fat, vitamins A and C, sodium, potassium, and iron for men and women. Calcium intake also tended to be positively associated with intake of nuts, potatoes, sugar and sweeteners, soybeans and legumes, fruits, green and yellow vegetables, other vegetables, mushrooms, sea algae, fish and shellfish, eggs, and milk and dairy products for men and women. CONCLUSIONS: The characteristics of calcium intake in Japanese people were able to be clarified by using the baseline data of NIPPON DATA and the National Nutrition Survey.

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.

[Malnutrition and the risk of long-term care insurance certification or mortality. A cohort study of the Tsurugaya project].

OBJECTIVE: The purpose of this study was to propose a suitable cut-off point for the serum albumin value to predict which elderly individuals are qualified for long-term care insurance certification and those at risk of death. METHODS: The Tsurugaya Project was a comprehensive geriatric assessment conducted for community-dwelling elderly persons aged 70 years or older in Sendai, Japan. Of those participating, the 832 from whom consent was obtained and who were not qualified for long-term care insurance certification were adopted as subjects. Cut-off points on serum albumin levels were set every 0.1 g/dL from 3.5 g/ dL to 4.0 g/dL. The risk of incident certification of long-term care insurance or death (calculated by the Cox proportional hazards model), the frequency of the subjects, the sensitivity, the specificity and the positive predictive value of the category below each cut-off point were calculated. RESULTS: During 3 years follow-up, a total of 130 subjects either became certificated for long-term care insurance or died. On multivariate analyses, the risk of incident certification of long-term care insurance or death showed significantly increase with all cut-offpoints. The frequencies were 1.3% at 3.5 g/dL, 9.6% at 3.8 g/dL and 29.6% at 4.0 g/dL. The sensitivities were 5.4% at 3.5 g/dL, 18.5% at 3.8 g/ dL and 45.4% at 4.0 g/dL. The specificities were 99.4% at 3.5 g/dL, 92.0% at 3.8 g/dL and 73.4% at 4.0 g/dL. The positive predictive values were 63.6% at 3.5 g/dL, 30.0% at 3.8 g/dL and 24.0% at 4.0 g/dL. When the serum albumin cut-off point was set to 3.8 g/dL and the highest tertile level of the serum albumin value was used as a reference category, the sex- and age-adjusted hazard ratios (95% confidence intervals) were 2.1 (1.1-3.9) in those with serum albumin < or =3.8 g/dL, 1.5 (0.9-2.5) in those with the lowest tertile level and 1.0 (0.6-1.7) in those with the middle tertile level. CONCLUSION: This study suggested that a serum albumin value of 3.8 g/dL is a suitable cut-off point with regard to sensitivity, specificity and positive predictive value.

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.