Ayako Miura

Prevalence of Alzheimer's disease, vascular dementia and dementia with Lewy bodies in a Japanese population

Abstract We studied the prevalence of dementing disorders in a rural town of Japan (Amino‐cho), using a door‐to‐door two‐phase design. Of the 170 persons screened as having cognitive impairment, 142 cases were diagnosed as having dementia. The prevalence (cases/100 aged 65 years older) was 3.8 for all types of dementia, 2.1 for Alzheimers disease (AD), 1.0 for vascular dementia (VD) and 0.7 for other types of dementia. Among other types of dementia, there were four male patients with dementia with Lewy bodies (prevalence: 0.1), but no patients with frontotemporal lobar degeneration. The overall prevalence was higher in women for AD, while that of VD was the same in both sexes. With results similar to many previous studies in Western countries and some recent surveys in Japan, the present sudy clearly showed that AD is more prevalent than VD.

Soybean Isoflavones Reduce Postmenopausal Bone Resorption in Female Japanese Immigrants in Brazil: A Ten-Week Study

Objective: Some human studies and animal models of experimental osteoporosis have shown that soy isoflavones may be effective on bone health. In this study, we carried out an intervention study to explore the effects of dietary isoflavone on bone metabolism. Methods: Forty healthy female postmenopausal Japanese immigrants living in Brazil were divided into two groups: isoflavone-administered (n = 20) or placebo (n = 20). Subjects in the isoflavone-administered group ingested 37.3 mg per day for 10 weeks. The collection of 24-hour urine and the measurement of bone stiffness were performed at 0 and 10 weeks. Urinary excretion of isoflavones and bone resorption markers were analyzed. Results: Urinary isoflavone excretion in the isoflavone-administered group was significantly increased at weeks 3 and 10. Urinary excretion of bone resorption markers was reduced in the isoflavone-administered group, while the placebo group did not show any significant reduction. Differences in levels of urinary isoflavones and bone resorption markers between the two groups were significant. Conclusion: This study demonstrated that the bone resorption was associated with the intake of soy isoflavones in postmenopausal women, and continuous dietary intake of isoflavone may inhibit postmenopausal osteoporosis.

Estimation of caffeine intake in Japanese adults using 16 d weighed diet records based on a food composition database newly developed for Japanese populations

OBJECTIVE Previous studies in Western populations have linked caffeine intake with health status. While detailed dietary assessment studies in these populations have shown that the main contributors to caffeine intake are coffee and tea, the wide consumption of Japanese and Chinese teas in Japan suggests that sources of intake in Japan may differ from those in Western populations. Among these teas, moreover, caffeine content varies widely among the different forms consumed (brewed, canned or bottled), suggesting the need for detailed dietary assessment in estimating intake in Japanese populations. Here, because a caffeine composition database or data obtained from detailed dietary assessment have not been available, we developed a database for caffeine content in Japanese foods and beverages, and then used it to estimate intake in a Japanese population. DESIGN The caffeine food composition database was developed using analytic values from the literature, 16 d weighed diet records were collected, and caffeine intake was estimated from the 16 d weighed diet records. SETTING Four areas in Japan, Osaka (Osaka City), Okinawa (Ginowan City), Nagano (Matsumoto City) and Tottori (Kurayoshi City), between November 2002 and September 2003. SUBJECTS Two hundred and thirty Japanese adults aged 30-69 years. RESULTS Mean caffeine intake was 256.2 mg/d for women and 268.3 mg/d for men. The major contributors to intake were Japanese and Chinese teas and coffee (47 % each). Caffeine intake above 400 mg/d, suggested in reviews to possibly have negative health effects, was seen in 11 % of women and 15 % of men. CONCLUSIONS In this Japanese population, caffeine intake was comparable to the estimated values reported in Western populations.

Estimation of Trans Fatty Acid Intake in Japanese Adults Using 16-Day Diet Records Based on a Food Composition Database Developed for the Japanese Population

Background The Standard Tables of Food Composition in Japan do not include information on trans fatty acids. Previous studies estimating trans fatty acid intake among Japanese have limitations regarding the databases utilized and diet assessment methodologies. We developed a comprehensive database of trans fatty acid food composition, and used this database to estimate intake among a Japanese population. Methods The database was developed using analytic values from the literature and nutrient analysis software encompassing foods in the US, as well as values estimated from recipes or nutrient compositions. We collected 16-day diet records from 225 adults aged 30 to 69 years living in 4 areas of Japan. Trans fatty acid intake was estimated based on the database and the 16-day diet records. Results Mean total fat and trans fatty acid intake was 56.9 g/day (27.7% total energy) and 1.7 g/day (0.8% total energy), respectively, for women and 66.8 g/day (25.5% total energy) and 1.7 g/day (0.7% total energy) for men. Trans fatty acid intake accounted for greater than 1% of total energy intake, which is the maximum recommended according to the World Health Organization, in 24.4% of women and 5.7% of men, and was particularly high among women living in urban areas and those aged 30–49 years. The largest contributors to trans fatty acid intake were confectionaries in women and fats and oils in men. Conclusions Although mean trans fatty acid intake was below the maximum recommended intake of the World Health Organization, intake among subgroups was of concern. Further public health efforts to reduce trans fatty acid intake should be encouraged.

Within- and Between-Individual Variation in Energy and Nutrient Intake in Japanese Adults: Effect of Age and Sex Differences on Group Size and Number of Records Required for Adequate Dietary Assessment

Background Information on within- and between-individual variation in energy and nutrient intake is critical for precisely estimating usual dietary intake; however, data from Japanese populations are limited. Methods We used dietary records to examine within- and between-individual variation by age and sex in the intake of energy and 31 selected nutrients among Japanese adults. We also calculated the group size required to estimate mean intake for a group and number of days required both to rank individuals within a group and to assess an individual’s usual intake, all with appropriate arbitrary precision. A group of Japanese women (younger: 30–49 years, n = 58; older: 50–69 years, n = 63) and men (younger: 30–49 years, n = 54; older: 50–76 years, n = 67) completed dietary records for 4 nonconsecutive days in each season (16 days in total). Results Coefficients of within-individual variation and between-individual variation were generally larger in the younger group than in the older group and in men as compared with women. The group size required to estimate a group’s mean intake, and number of days required to assess an individual’s usual intake, were generally larger for the younger group and for men. In general, a longer period was required to rank women and older adults. Conclusions In a group of Japanese adults, coefficients of within-individual variation and between-individual variation, which were used to estimate the group size and number of records required for adequate dietary assessment, differed by age, sex, and nutrient.

The influence of age and body mass index on relative accuracy of energy intake among Japanese adults

OBJECTIVE To examine relationships between the ratio of energy intake to basal metabolic rate (EI/BMR) and age and body mass index (BMI) among Japanese adults. DESIGN Energy intake was assessed by 4-day semi-weighed diet records in each of four seasons (16 days in total). The EI/BMR ratio was calculated from reported energy intake and estimated basal metabolic rate as an indicator of reporting accuracy. SETTING Residents in three areas in Japan, namely Osaka (urban), Nagano (rural inland) and Tottori (rural coastal). SUBJECTS One hundred and eighty-three healthy Japanese men and women aged > or =30 years. RESULTS The oldest age group (> or =60 years) had higher EI/BMR values than the youngest age group (30-39 years) in both sexes (1.74 vs. 1.37 for men; 1.65 vs. 1.43 for women). In multiple regression analyses, age correlated positively (partial correlation coefficient, beta = 0.012, P < 0.001 for men; beta = 0.011, P < 0.001 for women) and BMI correlated negatively (beta = -0.031, P < 0.001 for men; beta = -0.025, P < 0.01 for women) with EI/BMR. CONCLUSION Age and BMI may influence the relative accuracy of energy intake among Japanese adults.

The influence of season and air temperature on water intake by food groups in a sample of free-living Japanese adults

Background/objectives:To examine the influence of season and climate (air temperature and humidity) on water intake by the food group in a sample of free-living Japanese adults.Subjects/methods:Four-nonconsecutive-day, semi-weighed dietary records were collected from each of the four seasons in a single 12-month period (16 days in total). The influence of season and climate on individual water intake by the food group was analyzed using a mixed linear model. Participants were 242 healthy adults (121 women aged 30–69 years and 121 men aged 30–76 years) from four areas in Japan.Results:For women and men together, the mean total water intake was 2230 g/day (highest in summer: 2331 g/day; lowest in winter: 2134 g/day). Fifty-one percent of water was derived from foods and the rest from beverages. In a mixed linear model adjusted for sex, age and body mass index, intake of water from foods decreased by 3.1 g/day and that from beverages increased by 8.4 g/day, with an increase in the mean outdoor air temperature on the survey day of 1 °C (both P<0.0001). The influence of humidity was nonsignificant.Conclusions:In contrast to previous findings in Western countries, half of water intake in Japanese adults was derived from foods. Water intake from beverages was positively associated with air temperature, whereas that from foods was inversely associated with air temperature.

Estimation of intakes of copper, zinc, and manganese in Japanese adults using 16-day semi-weighed diet records

Data for the intake of copper, zinc, and manganese in Japanese populations obtained by detailed diet assessment methods and the most recent version of the food composition database in Japan are scarce. Moreover, data on food sources which contribute to the intake of these nutrients in Asian countries, including Japan, are not available. Here, we estimated copper, zinc, and manganese intake and elucidated major food sources of these nutrients in a Japanese population. We collected 16-day diet records from 225 adults aged 30 to 69 years living in 4 areas of Japan. Intakes of copper, zinc, and manganese were estimated using the 16-day diet records and the latest version of the Food Composition Tables in Japan. Mean intakes of copper, zinc, and manganese were 1.2 mg/day, 8.2 mg/day, and 4.9 mg/day for women and 1.4 mg/day, 10.1 mg/day, and 5.1 mg/day for men, respectively. White rice was the largest contributor to the intake of copper, zinc, and manganese, accounting for approximately 20%-30% of the total intake of each.

Estimation of habitual iodine intake in Japanese adults using 16 d diet records over four seasons with a newly developed food composition database for iodine.

Although habitual seaweed consumption in Japan would suggest that iodine intake in Japanese is exceptionally high, intake data from diet records are limited. In the present study, we developed a composition database of iodine and estimated the habitual intake of iodine among Japanese adults. Missing values for iodine content in the existing composition table were imputed based on established criteria. 16 d diet records (4 d over four seasons) from adults (120 women aged 30-69 years and 120 men aged 30-76 years) living in Japan were collected, and iodine intake was estimated. Habitual intake was estimated with the Best-power method. Totally, 995 food items were imputed. The distribution of iodine intake in 24 h was highly skewed, and approximately 55 % of 24 h values were < 300 μg/d. The median iodine intake in 24 h was 229 μg/d for women and 273 μg/d for men. All subjects consumed iodine-rich foods (kelp or soup stock) on one or more days of the sixteen survey days. The mean (median) habitual iodine intake was 1414 (857) μg/d for women and 1572 (1031) μg/d for men. Older participants had higher intake than younger participants. The major contributors to iodine intake were kelp (60 %) and soup stock (30 %). Habitual iodine intake among Japanese was sufficient or higher than the tolerable upper intake level, particularly in older generations. The association between high iodine intake as that observed in the present study and thyroid disease requires further study.

Higher proportion of total and fat energy intake during the morning may reduce absolute intake of energy within the day. An observational study in free-living Japanese adults☆

BACKGROUND Although the distribution of energy intake throughout the day appears to impact overall daily energy intake, little is known about the ad libitum distribution of energy intake. OBJECTIVE Our aim was to investigate associations between the distribution of energy intake during the day and subsequent or overall energy intake, and food choice in free-living adults. DESIGN A total of 119 women and 116 men completed 16-day semi-weighed dietary records. The longitudinal dietary intake data for each participant were analyzed using a mixed model to examine the effect of energy intake at various times of day on subsequent or overall energy intake. RESULTS Mean proportion of total energy intake in the morning (4:00 a.m.-10:29 a.m.), afternoon (10:30 a.m.-4:59 p.m.) and evening (5:00 p.m.-3:59 a.m.) meal was 22.6%, 33.8% and 43.6% in men, and 24.7%, 36.5%, 38.8% in women, respectively. Proportion of energy intake (%) in the morning meal was significantly and negatively associated with energy intake (kcal) in the subsequent afternoon and evening meals, and consequently in the whole day in both sexes. This significant and negative association was also observed for proportion of energy intake (%) of fat, but not of carbohydrate or protein, in both sexes. Proportion of energy intake (%) in the morning meal was negatively associated with overall energy intake (kcal) from the group of meats, fish, and eggs in both sexes, and from the group of confectioneries and soft drinks in women. CONCLUSIONS More energy in the morning meal may reduce energy intake, especially that from fat, in the subsequent meals, and consequently in the whole day.