Tai-ichiro Takemoto

Falls Among Community‐Dwelling Elderly in Japan

Japanese have a lower incidence of hip fracture than Caucasians despite having lower bone mass. Hip fractures usually occur after a fall, and differing incidence rates of falls might explain the observed differences in hip fracture rates. To explore this hypothesis, we studied falls and related conditions among 1534 (624 men, 910 women) community‐dwelling people aged 65 years and over in Japan and compared the prevalence of falls to Japanese‐Americans living in Hawaii and to published studies of Caucasians. In Japan, 9% of the men and 19% of the women reported one or more falls during the past year. The prevalence of falls increased with age in both genders and was greater among women compared with men. In logistic regression models, having musculoskeletal disease, physical disability or limited activity increased the risk of falls by two to four times in both genders. Most fallers (92%) reported fear of future falls, and about one third of fallers reported that they went out less often as a result of their falls. Compared with native Japanese, the age‐standardized prevalence of falls among Japanese‐Americans was similar but about twice as high for Caucasians, which may explain the lower hip fracture risk of Japanese.

Relationship between falls and physical performance measures among community-dwelling elderly women in Japan

Background and aims: The relationship between falls and physical performance has focused on the frail elderly who have several health problems, particularly those in nursing homes or care facilities. It is important to clarify the relationship between falls and physical performance among the community-dwelling elderly. Methods: We examined the relationship between falls and physical performance measures (grip strength, chair stand time, functional reach, usual walking speed) among 402 community-dwelling Japanese elderly women aged 60 years and over. Results: Overall prevalence of falls was 21.1%, and increased with age. In univariate analysis, grip strength and functional reach were not significantly different between women who did and did not fall. Chair stand time of women who fell was longer than that of women who did not (p=0.05), and the usual walking speed of women who fell was significantly slower than that of women who did not fall (p<0.0001). Physical functioning significantly decreased with age; grip strength, functional reach and usual walking speed decreased, and chair stand time increased. Logistic regression analysis, adjusting for age and other covariates, showed that slower usual walking speed was significantly associated with falls, but grip strength and functional reach were not. Increased chair stand time had a borderline association (p=0.1). Conclusions: Our findings indicate that poor lower extremity function, especially walking ability, is an important risk factor for falls in elderly Japanese community-dwelling women.

Comparison of performance-based measures among native Japanese, Japanese-Americans in Hawaii and Caucasian women in the United States, ages 65 years and over: a cross-sectional study

BackgroundJapanese (both in Japan and Hawaii) have a lower incidence of falls and of hip fracture than North American and European Caucasians, but the reasons for these differences are not clear.Subjects and MethodsA cross-sectional study. We compared neuromuscular risk factors for falls using performance-based measures (chair stand time, usual and rapid walking speed, and grip strength) among 163 Japanese women in Japan, 681 Japanese-American women in Hawaii and 9403 Caucasian women in the United States aged 65 years and over.ResultsAfter adjusting for age, the Caucasian women required about 40% more time to complete 5 chair stands than either group of Japanese. Walking speed was about 10% slower among Caucasians than native Japanese, whereas Japanese-American women in Hawaii walked about 11% faster than native Japanese. Grip strength was greatest in Japan, which may reflect the rural farming district that this sample was drawn from. Additional adjustment for height, weight or body mass index increased the adjusted means of chair stand time and grip strength among Japanese, but the differences remained significant.ConclusionsBoth native Japanese and Japanese-American women in Hawaii performed better than Caucasians on chair stand time and walking speed tests, and native Japanese had greater grip strength than Japanese in Hawaii and Caucasians. The biological implications of these differences in performance are uncertain, but may be useful in planning future comparisons between populations.

Calcaneus Bone Mineral Density is Lower Among Men and Women with Lower Physical Performance

Abstract Fracture risk is influenced by both bone strength and by falls. Measures of physical function and performance are predictors of falls. However, the interrelationships among bone mineral density (BMD), regular physical activity, and measures of physical performance are not well known. We studied 447 community-dwelling Japanese people aged 40 years and over (96 men and 351 women) to examine the association of calcaneus BMD with measures of physical performance (grip strength, walking speed, chair stand, and functional reach) and regular physical activity. Calcaneus BMD decreased with age by approximately 25% in men and 42% in women. Measures of physical performance decreased with age by approximately 30% in both genders, however, performance on the chair stand test declined by approximately 60%. There were only minimal differences in performance measures and calcaneus BMD between people with and those without regular physical activity in both genders, and most differences were not significant. However, there were significant BMD increases of 3–6% per standard deviation (SD) increase in all performance measures for women and a 7% increase in BMD per SD increase in grip strength for men, after adjusting for age. These associations remained after additional adjustment for body mass index and regular physical activity. These findings suggest that bone density and physical function decline markedly in both men and women with age, and that low BMD and poor function tend to occur together, which would increase fracture risk more than either risk factor alone.

Prevalence of joint pain is higher among women in rural Japan than urban Japanese-American women in Hawaii

OBJECTIVE Environmental factors such as farming contribute to the frequency of joint symptoms. The purpose of this study is to explore the possible role of environment (lifestyle), by comparing the prevalence of joint pain between Japanese in a rural farming district in Japan and in urban Hawaii. SUBJECTS AND METHODS Current or previous pain at specific joints was surveyed among 222 women in rural Japan and 638 Japanese women in urban Hawaii aged 60–79. The age adjusted prevalence was compared using logistic regression. RESULTS The prevalence of pain at one or more joints was approximately 70% in Japan and 50% in Hawaii. The prevalence of knee pain in Japan ranged from 36% at ages 60–69 years to 53% at 70–79 years (mean 41%), whereas knee pain affected only 20% of women in Hawaii in both age groups. The odds ratio (and 95% CI) was 3.2 (2.1, 4.8) for knee pain, and 4.0 (2.2, 7.4) for mid-back pain in Japan, compared with Hawaii. Pain was also significantly more common in Japan at the shoulder, elbow, and ankle, but not at other joints. Women in Japan were shorter and weighed less than in Hawaii. Adjustment for body mass index increased the odds ratios to 4.4 (2.9, 6.8) for knee, and 4.5 (2.4, 8.5) for mid-back pain. CONCLUSION Although the potential influence of cultural factors or other sources of bias cannot be ruled out, the large differences in the prevalence of pain at specific joints suggest that environmental factors are probably responsible, because both populations are of similar genetic stock.

Ecological structure and incidence rates of schizophrenia in Nagasaki City

The purpose of this study was to investigate the relationship between incidence rates of schizophrenia and residential features in Nagasaki City, Japan. Social features of residents in 259 areas in the Nagasaki City ecological structure were determined using the results of the 1980 national census. Six residential factors ‐ employment status, occupational and academic career, household status, length of residence, housing tenure and young male predominance ‐ were selected as factors that clearly reflect residential differentiation of residents. Contrary to the findings of many other studies conducted in Western cities, no statistically significant differences were observed, although it seemed that incidence rates were comparatively higher in the lower social classes. These results possibly reflect differences in cultural and social values and structures.

Appendicular bone mass and knee and hand osteoarthritis in Japanese women: a cross-sectional study

BackgroundIt has been reported that there is an inverse association between osteoarthritis (OA) and osteoporosis. However, the relationship of bone mass to OA in a Japanese population whose rates of OA are different from Caucasians remains uncertain.MethodsWe studied the association of appendicular bone mineral density (second metacarpal; mBMD) and quantitative bone ultrasound (calcaneus; stiffness index) with knee and hand OA among 567 Japanese community-dwelling women. Knee and hand radiographs were scored for OA using Kellgren-Lawrence (K/L) scales. In addition, we evaluated the presence of osteophytes and of joint space narrowing. The hand joints were examined at the distal and proximal interphalangeal (DIP, PIP) and first metacarpophalangeal/carpometacarpal (MCP/CMC) joints.ResultsAfter adjusting for age and body mass index (BMI), stiffness index was significantly higher in women with K/L scale, grade 3 at CMC/MCP joint compared with those with no OA. Adjusted means of stiffness index and mBMD were significantly higher in women with definite osteophytes at the CMC/MCP joint compared to those without osteophytes, whereas there were no significant differences for knee, DIP and PIP joints. Stiffness index, but not mBMD, was higher in women with definite joint space narrowing at the CMC/MCP joint compared with those with no joint space narrowing.ConclusionsAppendicular bone mass was increased with OA at the CMC/MCP joint, especially among women with osteophytes. Our findings suggest that the association of peripheral bone mass with OA for knee, DIP or PIP may be less clearcut in Japanese women than in other populations.

Selenium intake status in an Andean highland population

Abstract Nutritional selenium (Se) status in an Andean population living at high altitude (4000 m above sea level) was examined using dietary Se (DSe) intake. Mean (±SD) DSe intake was 47.7±16 μg/day for adult males (19 years old and above), and 36.6±13 μg/day for adult females. Two-thirds of the subjects were found to consume less Se than the U.S. Recommended Dietary Allowance values. The DSe levels among the subjects examined were marginally lower compared to values reported from other areas of the world. Their blood Se (whole blood Se, erythrocyte Se and serum Se), however, appeared to be maintained at a relatively high level with respect to the marginally lower DSe intake.

Daily Response of Blood Pressure to Day-to-Day Variation of Urinary Sodium to Potassium Ratio

The relationship between blood pressure and urinary sodium-to-potassium (Na/K) ratio was assessed in eight healthy men, none of whom used antihypertensive medications. Blood pressure and urinary sodium and potassium concentrations were measured for 11 to 33 days without any dietary restriction. For two of the eight subjects, the urinary Na/K ratio significantly correlated with systolic blood pressure (r=0.70 and 0.45, respectively), and in one of the two subjects, the urinary ratio also positively correlated with diastolic blood pressure (r=0.72). In the others, no relationship between the ratio and blood pressure was observed (r=-0.24 to 0.26). The results indicate that, in some individuals, the daily variation of urinary Na/K ratio is closely correlated with day-to-day changes in blood pressure level, and suggest that the urinary Na/K ratio is useful in the management of the daily sodium and potassium intake balance of hypertensive patients who need to restrict salt intake.

Urinary sodium/potassium ratio and prevalence of hypertension in two communities of different historical origin in Ohshima Island, Nagasaki, Japan

Urinary Na/K ratios and prevalence of hypertension were compared in two communities on the Ohshima Island, Nagasaki, Japan. The western area consisted of agricultural‐fishery community while the eastern area was a migrant/ex‐mining community. A subsistence agricultural‐fishery lifestyle was still seen in parts of the western community, while people of the eastern area were mostly consumers of purchased food. Urinary Na/K ratio was higher in the eastern area than in the western area in both men (5.2 vs 4.2) and women (4.8 vs 4.4). Since both population groups shared the same physical environment, the results suggest that the historical background of the communities influenced food habits including sodium and potassium intake. However, the hypertensive rates did not differ between the areas. Our results suggest that the prevalence of hypertension in both communities could reach a plateau at a given urinary Na/K ratios.