Impact of dietary habits on renal function in Saku, a rural Japanese town: a cohort study.

BACKGROUND: High protein intake leads to a decline in renal function in the advanced stages of chronic kidney disease (CKD). An effective diet for maintaining renal function in healthy individuals or patients in the early stages of CKD has not been established. This cohort study was conducted in Saku, Nagano Prefecture, Japan, to investigate the impact of dietary habits on renal function. METHODS: In this cross-sectional cohort study, we used the Saku Control Obesity Program (UMIN000016892), including 4,446 participants who submitted a brief-type self-administered diet history questionnaire and underwent routine physical examination. The amount of food intake was divided into quartiles. After adjusting for age and sex, multivariate logistic regression analysis was used to calculate the odds ratio (OR) for the risk of developing CKD (estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m2). RESULTS: In total, 3,899 participants were analyzed. The overall prevalence of patients with eGFR < 60 mL/min/1.73 m2 was 11% (n = 434, male; 7.1%, female; 4.1%). The groups with a high intake of chicken (approximately 63.4 g/day, adjusted OR: 0.632, P = 0.003), natto (fermented bean; approximately 21.7 g/day, adjusted OR: 0.679, P = 0.01), and plant protein (approximately 0.8 g/ideal body weight/day, adjusted OR: 0.695, P = 0.042) showed a low risk of developing CKD compared to the group with the lowest intake. CONCLUSIONS: Our cross-sectional study showed that the intake of chicken meat, natto, and plant protein was associated with high eGFR levels. This information can be of value for preventing CKD incidence in healthy Japanese individuals.

Dietary therapy with low protein genmai (brown rice) to improve the gut-kidney axis and reduce CKD progression.

Low protein rice can be part of a nutritionally adequate dietary pattern in the prevention of chronic kidney disease. We developed a low protein fermented genmai (brown rice) LPFG) to improve chronic kidney disease (CKD) management. The principal functional features of brown rice are retained in LPFG, lessening the negative spiral of gut-kidney associative spiral attributable to uremic dysbiosis and a leaky gut. LPFG is characterized by (1) an energy value the same as white rice, (2) a protein content less than 0.2 g/ 100 g, (3) a potassium content almost zero, (4) phosphorus less than a quarter that of conventional rice, (5) the presence of dietary fiber, (6) having γ-oryzanol, and (7) antioxidant activity. Dietary therapy for CKD patients is challenged by the joint needs to provide enough energy and to restrict protein. Patients replaced staple foods with LPFG without side dish restriction. Preliminary study of intervention with 3 months of LPFG reduced constipation probably by increased Blautia wexlerae, Bifidobacteria, acetic acid, and a decrease in potentially harmful bacteria. Protein intake decreased from 60 to 50 g per day. Urinary protein excretion decreased from 510 to 300 mg per day, and ß2-microglobulin from 926 to 250 µg/L. Adherence to the LPFG diet enabled improvement in glomerular and tubular function.

Why and How the Indo-Mediterranean Diet May Be Superior to Other Diets: The Role of Antioxidants in the Diet.

The Seven Countries Study showed that traditional Japanese and Mediterranean diets are protective against cardiovascular diseases (CVDs). The Japanese diet is considered the healthiest because it provides Japanese populations with the highest longevity and health. DASH and Mediterranean-style diets are also considered healthy diets, although the Indo-Mediterranean-style diet may provide better protective effects among patients with CVDs compared to other diets. The concept of the Indo-Mediterranean type of diet was developed after examining its role in the prevention of CVDs in India, the value of which was confirmed by a landmark study from France: the Lyon Heart Study. These workers found that consuming an alpha-linolenic acid-rich Mediterranean-style diet can cause a significant decline in CVDs and all-cause mortality. Later in 2018, the PREDIMED study from Spain also reported that a modified Mediterranean-style diet can cause a significant decline in CVDs, type 2 diabetes mellitus (T2DM), and cancer. The Indo-Mediterranean diet may be superior to DASH and Mediterranean diets because it contains millets, porridge, and beans, as well as spices such as turmeric, cumin, fenugreek, and coriander, which may have better anti-inflammatory and cardioprotective effects. These foods are rich sources of nutrients, flavonoids, calcium, and iron, as well as proteins, which are useful in the prevention of under- and overnutrition and related diseases. It is known that DASH and Mediterranean-style diets have a similar influence on CVDs. However, the Indo-Mediterranean-style diet may be as good as the Japanese diet due to improved food diversity and the high content of antioxidants.

Dietary Approaches to Stop Hypertension via Indo-Mediterranean Foods, May Be Superior to DASH Diet Intervention.

Western-type diet with high salt and sugar, sedentary behavior, obesity, tobacco and alcoholism are important risk factors for hypertension. This review aims to highlight the role of western diet-induced oxidative stress and inflammation in the pathogenesis of hypertension and the role of various types of diets in its prevention with reference to dietary approaches to stop hypertension (DASH) diet. It seems that it is crucial to alter the western type of diet because such diets can also predispose all CVDs. Western diet-induced oxidative stress is characterized by excessive production of reactive oxygen species (ROS) with an altered oxidation-reduction (redox) state, leading to a marked increase in inflammation and vascular dysfunction. Apart from genetic and environmental factors, one important cause for differences in the prevalence of hypertension in various countries may be diet quality, deficiency in functional foods, and salt consumption. The role of the DASH diet has been established. However, there are gaps in knowledge about the role of some Indo-Mediterranean foods and Japanese foods, which have been found to decrease blood pressure (BP) by improving vascular function. The notable Indo-Mediterranean foods are pulses, porridge, spices, and millets; fruits such as guava and blackberry and vegetables, which may also decrease BPs. The Japanese diet consists of soya tofu, whole rice, in particular medical rice, vegetables and plenty of fish rich in fish oil, fish peptides and taurine that are known to decrease BPs. Epidemiological studies and randomized, controlled trials have demonstrated the role of these diets in the prevention of hypertension and metabolic diseases. Such evidence is still meager from Japan, although the prevalence of hypertension is lower (15-21%) compared to other developed countries, which may be due to the high quality of the Japanese diet. Interestingly, some foods, such as berries, guava, pumpkin seeds, carrots, soya beans, and spices, have been found to cause a decrease in BPs. Omega-3 fatty acids, fish peptide, taurine, dietary vitamin D, vitamin C, potassium, magnesium, flavonoids, nitrate and l-arginine are potential nutrients that can also decrease BPs. Larger cohort studies and controlled trials are necessary to confirm our views.

Low-Protein Diet: History and Use of Processed Low-Protein Rice for the Treatment of Chronic Kidney Disease.

The epidemiology of chronic kidney disease (CKD) shows increasing trends in prevalence and mortality and has become the leading health problem worldwide. Reducing the amount of proteins ingested from rice is an easy way to control the total intake of proteins, saving energy sources, particularly in rice-eating countries. In Japan, low-protein white rice had been developed, but the taste and function were not satisfactory for CKD patients. We reviewed the brief history of low-protein dietary therapy for renal diseases and the recent development of low-protein processed brown rice (LPBR). The new LPBR is characterized by a low-protein content, the same energy content as white rice, low potassium and phosphorus contents, and high amounts of dietary fibers, γ-oryzanol, and antioxidant activity. Dietary fibers and γ-oryzanol would stabilize intestinal microbiota and improve uremic dysbiosis and leaky gut syndrome. All these features suggest that the health benefits of LPBR extend to preventing CKD progression and enhancing the quality of life (QOL) of patients with CKD.

Tratamiento ayurveda (Virechana y Basti) y cambios de la microbiota intestinal a nivel de Phylum y especie / Ayurveda Treatment (Virechana and Basti) and Changes of Intestinal Microbiota at Phyla and Species Level

Introducción: Se han analizado terapias ayurvédicas y prácticas médicas para un grupo de pacientes en Japón. La característica del tratamiento ayurvédico es una desintoxicación con una gran cantidad de tratamiento con aceite mediante un masaje con aceite en la superficie del cuerpo y una terapia de purificación con ghee o aceite de hierbas especialmente preparado. Los cambios de la microbiota intestinal durante estos tratamientos no han sido bien estudiados. Mé- LA PRENSA MÉDICA ARGENTINA Ayurveda Treatment (Virechana and Basti) and Changes of Intestinal Microbiota at Phyla and Species Level 79 V.107/Nº 2 todo: Los participantes fueron reclutados de la Clínica Hatai Ayurveda en Tokio. La terapia de Virechana, una terapia de purificación o la terapia de Basti (decocción y enema de aceite) se llevó a cabo en 13 pacientes con diversas manifestaciones. Todos los participantes proporcionaron el detalle de su estilo de vida, hábitos dietéticos, enfermedades pasadas y presentes mediante el cuestionario, y se registró la condición precisa durante la admisión al final del campamento. Se tomaron muestras fecales a la entrada, durante el tratamiento, al alta y tres semanas después para analizar la microbiota intestinal por el gen seqyebcubg 16srRNA. Resultados: el peso corporal disminuyó aproximadamente un 5% con la terapia de Virechana, mientras que no ocurrió con Basti, pero la grasa corporal aumentó un 4% (2,2 kg) en promedio en ambos grupos. Varias manifestaciones clínicas de los participantes mejoraron, especialmente en una erupción cutánea y un cambio atópico. El paciente deprimido también remitió mejoras en sus ganas de vivir. En su mayoría son vegetarianos y tenían más Bacteroides (48.09 ± 7.51%), Firmicutes (38.27 ± 10.82%) y Actinobacteria (3.30 ± 3.58%) que los omnívoros que tenían más Proteobacteria (10.73 ± 4.75%), Fusobacteria (2.40 ± 6.25%) y cianobacterias (0,09 ± 0,24%). Cuando los grupos se dividieron por el consumo de aceite, los usuarios de ghee mostraron más Fusobacterium y menos Firmicutes y Actinobacteria. La terapia con Virechana provocó cambios notables en la microbiota después del pretratamiento, como la disminución de Firmicutes y el aumento de Proteobacterias. A nivel género-especie, destacan el aumento de Enterobacteriaceae y la pérdida de Akkermansia municiphila. Niruha Basti y Matra Basti disminuyeron Firmicutes y aumentaron Proteobacteria (p = 0.096). Fusobacterium también aumentó. Después del alta, la Proteobateria se mantuvo alta, pero Firmicutes regresó al 30% en promedio, oscilando entre el 25% y el 50%. Tres semanas después, la variedad aumentó con Fusobacterium, Verrucomicrobia, Tenericutes y Lentisphaerae. La variedad de especies también aumentó tres semanas después. Conclusión: Varias quejas de los participantes mejoraron por el tratamiento ayurvédico con una gran cantidad de tratamiento de aceite por masaje de aceite de superficie corporal y terapia de purga. Causó cambios en la microbiota intestinal y los metabolitos bacterianos pueden afectar las lesiones cutáneas y la salud mental como la sensación depresiva

The associations of eating behavior and dietary intake with metabolic syndrome in Japanese: Saku cohort baseline study.

BACKGROUND: The prevention of metabolic syndrome (MetS) is a major public health concern in Japan. The effects of the relationship between eating behavior and nutritional intake on MetS remained unclear. To evaluate nutrition's role in preventing or exacerbating MetS, we examined the associations among eating behavior, nutritional intake, and MetS for the baseline study in the cohort subjects undergone health checkups. METHODS: Four thousand and four hundred forty-seven Japanese men and women were enrolled at the Saku Central Hospital. They received an anthropometric and clinical examination and were assessed for present illness, lifestyle factors such as physical activity, smoking, drinking, and dietary habits at the enrollment. Eating behavior was analyzed by the Sakata's Eating Behavior Questionnaire. Dietary assessment was made using a brief self-administered diet history questionnaire. Two thousand and six hundred two men and 1844 women aged more than 20 were analyzed. RESULTS: The mean age in men and women were 59.2 and 58.4 years old and the mean body mass index (BMI) were 23.7 and 22.3 kg/m2, respectively. The percentages of MetS were 20.6 in men and 6.1 in women. In some nutrients, significantly higher energy-adjusted intakes in subjects without MetS than with Mets appeared both in men and women after age adjustment. After adjusting by age, energy-adjusted intake beverages in men and cereals in women were significantly higher in subjects with MetS than those without MetS. The scores of all the categories in eating behavior were significantly worse in subjects with MetS than those without MetS. CONCLUSIONS: The differences in dietary intake between subjects with Mets and without Mets were relatively small. The scores of all the categories in eating behavior were worse in subjects with MetS than without MetS. It was suggested that the problem lay in the quality of diet, not in the quantity, caused by bad eating habits. The potential influence of eating behavior and nutritional intake on MetS was presented in men and women.

Association between selective IgA deficiency and COVID-19.

The purpose of this study was to propose a hypothesis that there is a potential association between the incidence of selective IgA deficiency in various countries and COVID-19 cases. The number of deaths due to COVID-19 increased in clear proportion to the number of infected patients, and the difference in the number of deaths by country was due to the difference in the number of infected patients. The frequency of selective IgA deficiency has a strong positive correlation with the prevalence of COVID-19 per population. The low infection rate contributed to the low death rate from COVID-19 in Japan, suggesting that the extremely low frequency of selective IgA deficiency may be a contributing factor.

Energy Expenditure in Free-Living Japanese People with Obesity and Type 2 Diabetes, Measured Using the Doubly-Labeled Water Method.

We determined the total energy expenditure (TEE) of healthy overweight or obese people, and those with impaired glucose tolerance and/or impaired fasting glycemia (IGT/IFG), or type 2 diabetes (T2DM) using the doubly-labeled water method. As a second purpose, we compared the measured TEE with the target energy intake recommended in the treatment guidelines for diabetes. The participants were normal glucose tolerance (NGT), and IGT/IFG (n=11) and T2DM (n=9) patients, who were 50-59 y and had a body mass index >25 kg/m2. The median TEE/body mass (BM) values were 32.6, 33.3, and 34.4 kcal/kg BM and the TEE/target BM values (target BM: BM at a BMI of 22 kg/m2) were 43.7, 50.2, and 46.5 kcal/kg target BM for each group, respectively, and did not differ significantly among them. Obese Japanese participants with T2DM in this study had lower TEE/BM than previously studied in non-obese participants with T2DM. In IGT/IFG or T2DM patients, if 30 kcal/kg target BM was used as the energy coefficient, on the basis of the treatment guidelines, the difference between TEE and the target energy intake would be -1,174±552 kcal (-38±11%). When 35 kcal/kg target BM was used as the energy coefficient, the difference between TEE and the target energy intake would be -877±542 kcal (-27±13%). Thus, the energy coefficients used to estimate target energy intake during lifestyle modification in obese/overweight patients with T2DM are considered to be quite low during the first step of diet therapy.

Covid-19 and dietary socioecology: Risk minimisation.

Pandemics have shaped humanity over and over again, but the coronavirus outbreak of 2019-2020 is in a world at the tipping point of catastrophic climate change. Its origins and distinction derive from over-population with inequity and an industrial revolution since the 17th century which has exploited fossil fuels as a globalised energy source, a period now described as the anthropocene. Asymptotic ecosystem loss and dysfunction, for people whose being is socioecological, makes ultimate survival tenuous. Microbial forms of life jump species when habitats are destroyed, or their host misused. Our innate immunity depends on our general health and fitness- social, mental, physical, and nutritional, in step with nature and its rhythms through walking in it, enjoying sunlight and sleep. Biodiversity and the associated benefit of food variety, after being breast-fed, is the key descriptor of a healthful, sustainable, accessible, and acceptable way of eating. How this pattern might contribute to our resilience in the face of a highly transmissible and biologically evasive virus is becoming clear. It may also be possible to compliment usefully preventive vaccination and therapeutic healthcare and rehabilitation through a greater understanding of our nutritional biology.

Effects of 1-year weight loss intervention on abdominal skeletal muscle mass in Japanese overweight men and women.

BACKGROUND AND OBJECTIVES: Limited information is available on how weight loss intervention programs affect skeletal muscle mass especially in trunk. METHODS AND STUDY DESIGN: A total of 235 overweight Japanese men and women aged 40-64 years with a body mass index of 28.0 to 44.8 kg/m2 participated in this randomized controlled intervention study. They were randomly divided into a lifestyle intervention group and control group. Before and after the one-year lifestyle intervention for weight loss an abdominal transverse image was acquired by computed tomography. The cross-sectional areas (CSAs) of visceral fat, subcutaneous fat, and skeletal muscle of rectus abdominis, abdominal oblique, iliopsoas, and erector spinae muscle were calculated. RESULTS: The body weight changed by approximately -5% in the intervention groups. The corresponding values for subcutaneous fat and visceral fat CSAs were -10.8 to -17.5% in both sexes. The reductions observed in skeletal muscle CSAs were significantly less (-6.0% and -7.2% in the men and women intervention groups respectively) than those in fat tissue CSAs. The CSA of each of the four skeletal muscle groups also significantly decreased; however, after adjustments for body weight at each time point, only reductions in the iliopsoas muscle in both sex and abdominal oblique muscles in men remained significant. CONCLUSIONS: The lifestyle weight loss intervention might reduce the relative amount of the abdominal skeletal muscles especially in iliopsoas muscle.

Association of visceral fat area with abdominal skeletal muscle distribution in overweight Japanese adults.

BACKGROUND: Quantitative evaluation of visceral fat mass and skeletal muscle mass is important for health promotion. Recently, some studies suggested the existence of adipocyte-myocyte negative crosstalk. If so, abdominal skeletal muscles may easily and negatively affected not only by the age but also the visceral fat because age-related reduction in abdominal region is greater compared with limbs. OBJECTIVE: We cross-sectionally examined the existence of quantitative associations between visceral fat area and abdominal skeletal muscle distribution in overweight people. METHODS: A total of 230 Japanese males and females who aged 40-64 years and whose body mass index (BMI) was 28.0-44.8kg/m2 participated in this study. The cross-sectional area (CSA) of the visceral fat, subcutaneous fat, and abdominal skeletal muscles, namely, the rectus abdominis, abdominal oblique, erector spinae, and iliopsoas muscles were measured by the computed tomography images. RESULTS: Stepwise regression analyses revealed the existence of sex difference in the relation between visceral fat CSA and other morphological variables. In males, BMI was a positive, and the iliopsoas muscle group CSA was a negative contributor of the visceral fat CSA. In females, both age and BMI were selected as positive contributors. CONCLUSION: These data suggested that the visceral fat CSA may negatively associated with iliopsoas muscle group CSA in males. In females, the visceral fat CSA was not significantly related to the distribution of the abdominal skeletal muscle groups.

Low-protein diet for the prevention of renal failure.

The prevalence of chronic kidney disease (CKD) is estimated to be 8-16% worldwide, and it is increasing. CKD is a risk factor for heart attack and stroke, and it can progress to kidney failure requiring dialysis or transplantation. Recently, diabetic nephropathy has become the most common cause of CKD. In Japan, the cumulative probability of requiring hemodialysis by the age 80 years is 1/50 in males and 1/100 in females. The number of patients under hemodialysis in Japan exceeded 320,000 in 2014, among which 38,000 were newcomers and 27,000 died.The annual medical costs of hemodialysis are 1.25 trillion yen in Japan, representing 4% of the total national medical expenditures in 2014. A low-protein diet (less than 0.5 g/kg b.wt.) is a very effective intervention. Low-protein rice (1/10 to 1/25 of the normal protein contents) is helpful to control the consumption of proteins, decreasing at the same time the intake of potassium and phosphate.Protein restriction is indicated as soon as the eGFR becomes lower than 60 ml/min/1.73 m2 body surface, in order, to slow disease progression. The newly developed low-protein Indica rice is expected to help many CKD patients in China and Southeast Asia.

Cross-sectional association of the number of neighborhood facilities assessed using postal code with objectively measured physical activity: the Saku cohort study.

Objectives The aim of this study was to examine the association between the number of neighborhood facilities that were assessed according to postal code and objectively measured physical activity by using an accelerometer in community-dwelling Japanese people.Methods The participants included 1,274 Japanese people aged 30-84 years from the Saku cohort study. As neighborhood facilities related to physical activity, we extracted information regarding train stations, supermarkets/convenience stores, postal offices/banks, hospitals/clinics, public offices/community centers, cultural facilities/public children's houses, parks, and sports facilities by using each participant's postal code from the online version of the iTownPages directory published by Nippon Telegraph and Telephone Corporation (NTT) and the official homepage of the Saku City Government Office. We measured each participant's physical activity level using an accelerometer, and calculated the average daily step count and the average weekly period of moderate-to-vigorous intensity (≥3 metabolic equivalents of tasks [METs]) physical activity. The association between two selected physical activity-related variables and the numbers of eight types of neighborhood facilities were analyzed by multivariate logistic regression analysis for people aged 30-64 years and for those aged over 65 years.Results On multivariate logistic regression analysis, meeting the 23 METs h/week of moderate-to-vigorous intensity physical activity was significantly and positively associated with the number of supermarkets/convenience stores in the neighborhood in both age groups. In addition, meeting the desired daily step count outlined in the Japanese National Health Promotion guidelines was positively related to the number of postal offices/banks for people aged over 65 years.Conclusion The results of this study suggest that a sufficient number of neighborhood facilities (i.e., stores, banks, and postal offices) is closely associated with the promotion of physical activity.

The relationship of body composition to daily physical activity in free-living Japanese adult men.

The objective of the present study was to investigate whether a previously reported apparent negative relationship between fat mass and daily physical activity in Japanese adult women would also be observed in Japanese adult men. The subjects were grouped into quartiles of BMI and body fat percentage (%BF). The number of steps walked each day and the duration of light- to vigorous-intensity physical activity were assessed by an accelerometer over the same period of time as for the doubly labelled water experiment. The results showed that BMI negatively correlated with the number of steps and time spent in moderate-intensity physical activity, whereas %BF showed a negative relationship with physical activity-related energy expenditure (PAEE)/body weight (BW) and physical activity level. The analysis of data using %BF quartiles revealed that PAEE/BW decreased from the second quartile in which the BMI was < 25 kg/m2. These observations are similar to those reported in our previous study in Japanese adult women. These cross-sectional studies cannot prove causality, and that obesity causes physical inactivity may be the case. However, the results of the present study provide information regarding which physical activity variables should be used in longitudinal studies.

Low-molecular-weight adiponectin and high-molecular-weight adiponectin levels in relation to diabetes.

OBJECTIVE: To evaluate the association between adiponectin complexes (high-molecular-weight [HMW], middle-molecular-weight [MMW], and low-molecular-weight [LMW] adiponectin) and diabetes. DESIGN AND METHODS: We conducted a case-control study, based on a cohort in Saku, Japan. Among 2565 participants, 300 participants with diabetes and 300 matched controls (430 men and 170 women) were analyzed. RESULTS: After adjusting for age, physical activity, hypertension, family history, alcohol use, smoking, and menopausal status, total, HMW, and LMW, but not MMW adiponectin levels were inversely associated with diabetes: total adiponectin, odds ratio comparing the highest with the lowest quartiles, 0.46 (95% confidence interval, 0.25-0.82; P for trend = 0.046); HMW, 0.40 (95%CI, 0.22-0.72; P = 0.046); MMW, 1.04 (95%CI, 0.60-1.77; P = 0.81); and LMW, 0.51 (95%CI, 0.29-0.89; P = 0.01). The associations between total and HMW adiponectin and diabetes attenuated after adjustment for BMI (P = 0.15 and 0.13, respectively), but LMW remained (P = 0.04). When stratified by sex, LMW adiponectin levels were associated with diabetes in men only. None of the associations were significant after adjustment for HOMA-IR. CONCLUSIONS: Decreased LMW, total, and HMW adiponectin levels are associated with diabetes. These associations may be secondary to adiposity or insulin resistance.

BMI percentile curves for Japanese men and women aged 20-79 years who underwent a health check-up in 1980 and 2005.

OBJECTIVE: To establish body mass index (BMI) percentile curves for adults and to compare these in 1980 with those in 2005 among Japanese men and women. METHODS: Participants included 8080 community residents aged 20-79 years who had a health check-up in 1980 and 5616 community residents aged 20-79 years who had a health check-up in 2005. Sex-specific percentile curves for BMI were constructed using the LMS method. We presented the 3rd, 5th, 15th, 25th, 50th, 75th, 85th, 95th, and 97th percentile curves. RESULTS: From 1980 to 2005, the BMI percentile values of men increased, especially the 95th and 97th percentile values in men aged 20-39 years. The BMI distribution of young men in 2005 was wider than that in 1980. From 1980 to 2005, the 50th percentile values of women in 2005 were lower than those in 1980. However, the 95th percentile values of women increased among women aged less than 50 years. CONCLUSION: We were able to confirm the existence of BMI percentile values depending on date, age, and sex by establishing BMI percentile curves.

Age differences in the risk of diabetes incidence according to body mass index level in Japanese women.

OBJECTIVE: To investigate the age differences in the risk of diabetes incidence according to body mass index (BMI). METHODS: For an average of 10.3 years, this study prospectively followed a cohort of 4725 women aged 30-69 years without diabetes at a baseline health check-up conducted between April 1990 and March 1992. Diabetes onset was identified by fasting and random plasma glucose level, HbA1c or the medical treatment for diabetes by questionnaire. We stratified the subjects according to age (30-39, 40-49, 50-59 and 60-69 years), and calculated the risk of diabetes incidence according to BMI categories (<18.5, 18.5-22.9, 23.0-24.9 and ≥25.0 kg/m(2)) using the Cox proportional hazards model. RESULTS: During 48,866 person-years of follow-up, 392 subjects developed diabetes. Using the normal group as the reference, the HR (95% CI) for diabetes incidence was elevated in obese women of all ages, ranging from a high of 4.72 (1.79-12.40) for women who were 30-39 years of age, to a low of 1.54 (1.02-2.33) for those who were 50-59 years of age. CONCLUSIONS: The risk of diabetes incidence according to BMI is different among different age groups of Japanese women. Obese is a strong risk factor for diabetes incidence among women of all ages, and especially among young adults.