Kazutoshi Nakamura

Reliability of self-reported body height and weight of adult Japanese women

The purpose of this study was to validate the self-reported body height and weight of adult Japanese women. The subjects were women, aged 20-42 years, who participated in a survey on eating disorders in women in 1995. Physically measured height and weight data were obtained for 368 (89.8%) of the 469 women who self-reported their height and weight. The report-based heights and weights were compared with the measured values. The correlation coefficients for height and weight were 0.990 and 0.963 (p < 0.0001), respectively. Mean reported height was 0.1 cm shorter and mean reported weight 0.2 kg lighter than the measured values. Shorter women tended to report a taller height than their actual height, and heavier women to report a lower weight than their actual weight. Despite these limitations, the self-reported heights and weights of adult Japanese women were precise and accurate, and their use in epidemiological surveys is considered acceptable.

Low serum concentrations of 25-hydroxyvitamin D in young adult Japanese women: a cross sectional study

OBJECTIVES The vitamin D nutrition status of young adult women is unclear, but a recent preliminary report suggested that they may have vitamin D insufficiency. This study assessed the serum concentrations of 25-hydroxyvitamin D (25[OH]D), an index of vitamin D nutrition status, in young adult Japanese women in comparison with those in older women and investigated whether serum 25(OH)D concentrations are associated with other calcium-related hormones and bone mass. METHODS A cross sectional study of 77 healthy women, age 19 to 66 y, working in nursing homes in Japan was conducted in the winter of 1999 and 2000. The investigation included blood tests, forearm bone mass measurements, and a lifestyle questionnaire. RESULTS The mean serum 25(OH)D concentration in women younger than 30 y was 34.0 nmol/L (standard deviation [SD] = 11.0) and significantly lower than that in women 30 y and older (50.0 nmol/L, SD = 14.4). The proportion of subjects younger than 30 y who had serum 25(OH)D concentrations less than 30 nmol/L was 42.1% and was significantly higher (P < 0.001) than the proportion of those 30 y and older (10.3%). There was a weak but significant linear association between serum 25(OH)D concentrations and forearm bone mineral content (R(2) = 0.114, P = 0.0052) but not between serum 25(OH)D concentrations and bone mineral density. The association held after adjusting for body weight (R(2) = 0.139, P = 0.0111). Serum intact parathyroid hormone concentrations were within the normal range and not associated with serum 25(OH)D concentrations. CONCLUSIONS Serum 25(OH)D concentrations in young adult Japanese women (<30 y old) are lower than those of older adult women (30 to 66 y), and lower serum 25(OH)D concentrations are likely associated with lower forearm bone mineral content.

Fish as a major source of vitamin D in the Japanese diet.

OBJECTIVES We investigated the amount and sources of vitamin D in the Japanese diet by analyzing diet records collected over a 4-mo period. METHODS Dietary data for this study were provided by a nursing home in Niigata, Japan. Diet records, written by the nursing homes dietitian, for 122 consecutive days between September and December 1999, were used. The amount of food for an individual was weighed before cooking and recorded on the diet record. Vitamin D-containing foods, including fish, eggs, meat, and mushrooms, were selected from the diet records, and their vitamin D (vitamin D2 plus D3) per day was calculated by referring to the Standard Tables of Food Composition in Japan. RESULTS The overall average vitamin D intake per day was 7.10 microg (284 IU), which is about 70% of the recommended dietary allowance of 10 microg (400 IU). There were no significant differences in vitamin D values over the 4 mo (P = 0.822). Overall, the contribution of vitamin D from fish to total vitamin D intake was 90.7%, followed by mushrooms (4.4%), eggs (3.2%), and meat (1.7%). CONCLUSIONS Frequent fish intake appears to be an advisable health practice in terms of preventing vitamin D insufficiency in the elderly.

Eating problems in female Japanese high school students: A prevalence study

OBJECTIVES This study was conducted to estimate the prevalence of eating problems and to identify factors associated with the eating problems among Japanese high school girls. METHODS This study used a cross-sectional design. The study population was 3,032 female students attending three high schools in Fukushima, Japan. The 26-item version of the Eating Attitudes Test (EAT-26) was administered to assess eating problems. Inquiries were also made regarding possible risk factors for the eating problems. RESULTS Of the 2,685 subjects, 5.4% had a total EAT-26 score above the cutoff point (20 < or =). Logistic regression analysis demonstrated that older age, higher body mass index, a distorted body image, obsessive-compulsive tendency, and some familial issues were independently related to the eating problems. DISCUSSION The prevalence of eating problems in the Japanese female population was low compared with reports from Western countries. In addition, distorted body image was suggested to have the greatest influence on eating problems.

Vitamin D insufficiency in Japanese populations: from the viewpoint of the prevention of osteoporosis

Low levels of vitamin D nutrition (i.e., vitamin D insufficiency), which potentially cause osteoporosis, have been recognized as a common health problem for elderly people in European and North American countries, but there have been no studies on the prevalence of vitamin D insufficiency in Japan until recently. The aim of this article was to review descriptive features of serum 25-hydroxyvitamin D [25(OH)D] levels and vitamin D insufficiency in Japanese subjects. Reviewing 15 studies pertaining to vitamin D nutritional status recently published for various Japanese populations revealed that: (1) the prevalence of vitamin D insufficiency in active elderly people was as low as 5% or less; (2) the prevalence of vitamin D insufficiency was much higher (up to about 50%) in inactive elderly people than in active elderly people, depending on activities of daily living (ADL); (3) frequent fish consumption helps increase serum 25(OH)D concentrations, especially in winter; and (4) vitamin D nutrition in young women was poorer than people in middle and advanced ages, which may adversely affect bone metabolism. Future studies should focus on the effects of low vitamin D status on bone mass and fractures in Japanese subjects.

Long-term effects of the Niigata-Chuetsu earthquake in Japan on acute myocardial infarction mortality: an analysis of death certificate data

Objective: To determine if the Niigata-Chuetsu earthquake of October 2004 increased long-term mortality from acute myocardial infarction (AMI). Design: A comparative study of mortality rates before and after the earthquake, as well as between the disaster and control areas, by analysing death certificate data from 1 October 1999 to 30 September 2007. Setting: The disaster area and a control area in Niigata Prefecture (n = 2 448 025 in 1 October 2004) in Japan. Population: The total population of Niigata Prefecture observed for five years (12 333 429 person-years) before and three years (7 279 076 person-years) after the earthquake. Main outcome measures: Mortality from AMI (ICD-10, I21 and I22). Results: Overall mortality rates from AMI five years before and three years after the earthquake in the disaster area were 47.3 and 53.9 per 100 000 person-years, respectively. Change (+6.6 or +14.0%) was significantly different (p = 0.0008), compared to the control area, where mortality rates were 42.5 and 42.6 per 100 000 person-years, respectively, and was not significantly different (p = 0.9028). In men, a change in AMI mortality before and after the earthquake in the disaster area was +7.1 per 100 000 person-years (+13.4%, p = 0.0172), and +2.0 (+4.2%, p = 0.2362) in the control area. In women, a change in AMI mortality in the disaster area was +6.2 per 100 000 person-years (+14.9%, p = 0.0184) and −1.6 (−4.2%, p = 0.2735) in the control area. Conclusions: The Niigata-Chuetsu earthquake significantly increased long-term mortality from AMI in both men and women. Clinicians and policymakers in public health must recognise the need for long-term prevention of AMI in earthquake disaster areas.

Prevalence of anorexia nervosa and bulimia nervosa in a geographically defined area in Japan

OBJECTIVE Little has been understood regarding the frequency of eating disorders in Japan. This study was designed to identify the prevalence of anorexia nervosa (AN) and bulimia nervosa (BN) in Japan. METHOD We asked doctors in all of the relevant medical facilities (130 hospitals and 1,326 clinics) in Niigata Prefecture to report patients with DSM-IV-diagnosed eating disorders who appeared or were admitted between 20-24 October 1997. The response rate was 94.4%. RESULTS The estimated point prevalences of AN and BN were 4.79 and 1.02, respectively, per 100,000 females. Specifically for the age group of 15-29 years, the prevalence of AN was 17.10 and that of BN 5.79. DISCUSSION The prevalence of AN and BN in Japan is lower than that for European Caucasian populations. This result may be due to cultural and ethnic differences and/or it may be a transient phenomenon.

Body support effect on standing balance in the visually impaired elderly

OBJECTIVE To evaluate the effectiveness of body support in compensating for decreased standing balance stability in elderly persons with visual impairment. DESIGN Standing balance was measured in a cross-section of elderly persons from two nursing homes--one for aged individuals with visual impairment, the other for aged individuals without visual impairment. PARTICIPANTS The subjects were 44 visually impaired persons with a mean age of 79.0 yrs and 39 people without visual impairment, mean age 76.3 yrs. OUTCOME MEASURES The area of gravity-center sway was measured with subjects standing on a gravicorder for 30sec in three positions: (1) without support, (2) with cane, (3) with light support by touching a wall. RESULTS Both men and women in the visually impaired group swayed more than their sighted counterparts when standing without support, the only statistically significant difference between the two groups. For all subjects, the greatest degree of sway occurred when subjects stood unsupported, and the least sway occurred when subjects touched a wall for support. CONCLUSION In visually impaired elderly persons, touching a wall for body support while standing is more effective than using a cane.

Physical performance tests after stroke: reliability and validity.

ObjectiveTo evaluate the reliability and validity of the modified physical performance tests for stroke survivors who live in a community. DesignThe subjects included 40 stroke survivors and 40 apparently healthy independent elderly persons. The physical performance tests for the stroke survivors comprised two physical capacity evaluation tasks that represented physical abilities necessary to perform the main activities of daily living, e.g., standing-up ability (time needed to stand up from bed rest) and walking ability (time needed to walk 10 m). ResultsRegarding the reliability of tests, significant correlations were confirmed between test and retest of physical performance tests with both short and long intervals in individuals after stroke. Regarding the validity of tests, the authors studied the significant correlations between the maximum isometric strength of the quardriceps muscle and the time needed to walk 10 m, centimeters reached while sitting and reaching, and the time needed to stand up from bed rest. ConclusionsThe authors confirmed that there were significant correlations between the instrumental activity of daily living and the time needed to stand up from bed rest, along with the time needed to walk 10 m for the stroke survivors. These physical performance tests are useful guides for evaluating a level of activity of daily living and physical frailty of stroke survivors living in a community.

Appropriate Waist Circumference Cutoff Values for Persons with Multiple Cardiovascular Risk Factors in Japan: a Large Cross-sectional Study

Background In Japan, the current standard waist circumference cutoff value for persons with multiple cardiovascular risk factors remains controversial. In this study we aimed to analyze the health-check examination data from a large Japanese population and propose a revised waist circumference cutoff value. Methods Subjects of this study were 12,725 adults who underwent a health-check by thorough medical examination between April 2006 and March 2007. Medical examinations included measurement of waist circumference, fasting blood triglycerides, HDL cholesterol, glucose concentrations, blood pressure and collection of demographic characteristics. Receiver operating characteristic (ROC) curve analysis was utilized to find appropriate waist circumference cutoff values in relation to multiple cardiovascular risk factors with two or more of the following: dyslipidemia (hypertriglyceridemia or low HDL cholesterol), hypertension, and hyperglycemia defined by the Japanese criteria of metabolic syndrome. Results The average age of the subjects was 50.7 years (standard deviation [SD]: 8.8) for men and 49.7 years (SD: 8.6) for women. ROC curve analysis showed maximum sensitivity plus specificity at a waist circumference of 87 cm in men (0.66 and 0.62, respectively) and 83 cm in women (0.73 and 0.70). When analyzed by ten-year age groups, the ROC curves for younger age groups were shifted up and to the left compared to older age groups, but associations between cutoff values and age were not clear. Conclusion In Japan, the appropriate cutoff value of waist circumference for persons with multiple cardiovascular risk factors is 87cm for men and 83 cm for women.