Study design and baseline characteristics of a population-based prospective cohort study of dementia in Japan: the Japan Prospective Studies Collaboration for Aging and Dementia (JPSC-AD)

BACKGROUND@#The burden of dementia is growing rapidly and has become a medical and social problem in Japan. Prospective cohort studies have been considered an effective methodology to clarify the risk factors and the etiology of dementia. We aimed to perform a large-scale dementia cohort study to elucidate environmental and genetic risk factors for dementia, as well as their interaction.@*METHODS@#The Japan Prospective Studies Collaboration for Aging and Dementia (JPSC-AD) is a multisite, population-based prospective cohort study of dementia, which was designed to enroll approximately 10,000 community-dwelling residents aged 65 years or older from 8 sites in Japan and to follow them up prospectively for at least 5 years. Baseline exposure data, including lifestyles, medical information, diets, physical activities, blood pressure, cognitive function, blood test, brain magnetic resonance imaging (MRI), and DNA samples, were collected with a pre-specified protocol and standardized measurement methods. The primary outcome was the development of dementia and its subtypes. The diagnosis of dementia was adjudicated by an endpoint adjudication committee using standard criteria and clinical information according to the Diagnostic and Statistical Manual of Mental Disorders, 3rd Revised Edition. For brain MRI, three-dimensional acquisition of T1-weighted images was performed. Individual participant data were pooled for data analyses.@*RESULTS@#The baseline survey was conducted from 2016 to 2018. The follow-up surveys are ongoing. A total of 11,410 individuals aged 65 years or older participated in the study. The mean age was 74.4 years, and 41.9% were male. The prevalence of dementia at baseline was 8.5% in overall participants. However, it was 16.4% among three sites where additional home visit and/or nursing home visit surveys were performed. Approximately two-thirds of dementia cases at baseline were Alzheimer's disease.@*CONCLUSIONS@#The prospective cohort data from the JPSC-AD will provide valuable insights regarding the risk factors and etiology of dementia as well as for the development of predictive models and diagnostic markers for the future onset of dementia. The findings of this study will improve our understanding of dementia and provide helpful information to establish effective preventive strategies for dementia in Japan.

The Effect of the Weight Reduction on the Salivary Cortisol Levels of Judo Players

The purpose of this study was to investigate the effect of weight reduction prior to a competition on the salivary cortisol level for first-rate judo players. Subjects were divided into three groups by the weight reduction rate. On the day before the competition, the cortisol levels of the low- and high-weight reduction group showed a tendency to decrease and were significantly lower than that of the non-weight reduction group (p<0.05). However, with regard to the change in the stress indices, there was a difference between the high- and low-weight reduction groups. In the high-weight reduction group alone, there was a significant increase in the stress indices on the day before the competition (p<0.05). These findings suggest that the HPA axis is affected during the relatively early stage of weight reduction and mental stress is increased at the higher weight reduction rate.

The Unique Correlation between Anti-Mutagenicity of Human Saliva and Change in Body Weight

The purpose of this study was to investigate the effect of weight reduction on the anti-mutagenicity of human saliva. Subjects were 16 male college judo players. The anti-mutagenicity of the saliva was measured using the umu test. There was an inhibiting effect of the saliva on the mutagenicity of AF-2. However, a modifying effect of the saliva on Trp-P-1 was not observed. On the day before a competition and 7 days after the competition, the inhibiting capacity of the saliva for the mutagenicity of AF-2 decreased and increased in two non-weight reduction and two weight reduction groups, respectively. However, on the day before the competition, the changed body weights (r=−0.77, p<0.01) and BMI (r=−0.77, p<0.01) were significantly correlated with that of the inhibiting capacity of the saliva for the mutagenicity of AF-2. In addition, the BMI at 20 days before the competition was not significantly but markedly correlated with it (r=0.50, p=0.057). At 7 days after the competition, however, these correlations were not found. These findings suggest a unique correlation between the anti-mutagenicity of human saliva and body weight or BMI.

Effects of maximal exercise on nonspecific immunity in athletes under trained and detrained conditions / 体力科学

We investigated both the acute effects of maximal exercise and the chronic effects of training on nonspecific immunity in 15 winter-sports athletes during different periods of training : (a) before the athletic season, in summer, when the athletes were undertaking extensive endurance training to enhance aerobic capacity, (b) during the winter sports season, in early winter, when endurance and athletic training were being undertaken, and (c) after the winter sports season, in spring, when the athletes were resting (detraining for a month) . The mean value of the maximal oxygen uptake in each training period was (a) 65.4 (SD 4.6) mL·kg<SUP>-1</SUP>·min<SUP>-1</SUP>, (b) 63.1 (SD 5.5) mL· kg<SUP>-1</SUP>·min<SUP>-1</SUP>, and (c) 58.3 (SD 5.8) mL·kg<SUP>-1</SUP>·min<SUP>-1</SUP>, respectively. Following maximal exercise, acute peripheral leukocytosis due to lymphocytosis and neutrophila was observed in every period. The capacity of isolated neutrophils to produce reactive oxygen species upon stimulation with opsonized zymosan measure by luminol-dependent chemiluminescence (LDCL) was significantly enhanced after maximal exercise before and during the athletic season. However, the degree of enhancement was smaller during after-season detraining, suggesting that the conditioning state affected the exercise-induced changes in neutophil functional status. Serum opsonic activity also showed a similar pattern. As for the chronic effects of training, the resting values of the neutrophil count, especially the segmented neutrophil count, the neutrophil LDCL response and the serum IgG level, declined significantly in the pre-season training period. Since the subjects were engaged in exhaustive endurance training under heat exposure at that time, the nonspecific immune status might have been partially compromised due to chronic overload.

Effects of maximal exercise on blood leukocyte counts and neutrophil activity in athletes / 体力科学

Twenty endurance-trained athletes (five male speed-skaters, eleven male and four female cross-country skiers, 16-18 years) ran on a treadmill by a protocol of incremental graded increase in workload until exhaustion during an endurance training period in off-season summer. Immediately after exercise, all developed peripheral leukocytosis (1.9 times; p<0.01) due mainly to lymphocytosis (2.6 times; p<0.01) with a predominant effect on large granular lymphocyte (natural killer cell) count (5.9 times ; p<0.01) . Monocyte count was also enhanced 2.3 times (p<0.01) . These increases were transitory and returned to the pre-exercise levels 1 h later. Peripheral neutrophilia was also observed by 43% (p<0.01) immediately after exercise and remained elevated by 25% (p<0.01) 1 h after exercise, but a shift to the left did not take place. The capacity of isolated neutrophils to produce reactive oxygen species was assessed by luminol-dependent chemiluminescence which detects mainly myeloperoxidase (MPO) -mediated formation of such hyperreactive oxidants as HOCl. The maximum intensity of chemiluminescence (peak height) upon stimulation with opsonized zymosan was significantly enhanced following exercise (p<0.05) . Similar results were obtained when phorbol myristate acetate was employed as nonphagocytic soluble stimulus (p<0.01), suggesting that the capacity of neutrophils to degranulate MPO rather than phagocytosis was enhanced following exercise. In addition, the enhancements of chemiluminescence were positively correlated with the increase in segmented neutrophil count. These data indicate that maximal exercise not only mobilized mature neutrophils from the marginated pool into the circulation, but also augmented their capacity to generate reactive oxygen species of higher reactivity.

Epidemiological studies on apple pollinosis / 日本農村医学会雑誌

The subjective symptoms, various blood components, radioallergosorbent test (RAST) and others were examined for the patients who developed nasal allergy each year during the time of artificial apple pollination (before artificial pollination, during the peak of pollination and one month after pollination) compared with those for a control group, and the following results were obtained.<BR>1) The symptoms, the time of their appearance and the kind of symptoms were the same as those of the apple pollinosis.<BR>2) The change in the pattern of the eosinophile count was the same as that of the subjective symptoms.<BR>3) However, only 2 of the 11 patients had a RAST score of suspicious positive, and no difference was detected between these patients and the control group.<BR>From these findings, the many cases of suspected apple pollen allergy were cosidered to have been sensitized by other pollen which have common antigenicity to apple pollen in addition to true apple pollinosis, or to be mistaken diagnosis of other pollen allerg.

Studies on the Obesity Among the Women in Agncultural Villages Behavior of blood components with reference to the degree of lean and obesity / 日本農村医学会雑誌

The purpose of this study was the evaluation of the relationship between the degree of obesity (relative body weight ratio) and values of various components in blood. The degree of lean and obesity was defined as the ratio of actual body weight to standard body weight calculated by the method of katsura. Mean ± standard error and percent frequency of abnormal values of blood components were studied in 880 women with degree of lean and obesity from 80 to 170 % among the women in agricultural villages. The class mean in subjects with relative body weight ratio between 100 and 109 % was used as the standard class value for comparison with these values. The following results were obtained.<BR>1, Red blood count, hemoglobin and hematocrit values were significantly increased as the degree of obesity reached 130-140 %, compared to the standard class value, along with a significant fall of % frequency.<BR>2. Behavior of serum components with reference to the degree of obesity showed a marked component to component variation. The mean level of SGOT, SGPT, γ-GTP, TRIG, CHOL and UA rose along with the increase of the degree of obesity from the lean range via the standard body weight range to the obesity range. ALP, however, was high in the obese and lean ranges, and low in the standard body weight range. BUN showed a tendency in reverse. Electrolyte and creatinine values were not remarkably different between lean and obese persons.<BR>3. Marked changes of the mean levels were seen along with obesity in SGOT, SGPT, γ-GTP, cholesterol and triglyceride. Many of these showed significant increase of the mean in subjects with degree of obesity between 120 and 129 % compared to the standard class value. In subjects with degree of obesity of 140-149 %, frequency of abnormal values were significantly elevated. These results would suggest on an epidemiological basis that detailed examinations of the functional abnormalities of organs and environment in vivo thorugh blood testing is necessary for health control in subjects with degree of obesity of more than 140 % by Katsura method.