Kaori Iwane

Association between concentration of trace elements in serum and bronchial asthma among Japanese general population.

BACKGROUND AND AIMS A number of previous studies had revealed the association between trace elements in serum and bronchial asthma. However, only a few researches had focused on serum concentration of trace elements in a general population. In this study, an association between trace elements in serum and bronchial asthma was investigated in a general population. METHODS Subjects were 1025 volunteers (385 males and 640 females between ages 19 and 82 years old) who had participated in the Iwaki Health Promotion Project 2005. Bronchial asthma was diagnosed based on the European Community Respiratory Health Survey II according to the self-questionnaires on health conditions of subjects. The serum concentrations of certain trace elements (manganese, copper, zinc, selenium and iron) were measured and compared. Also, an association between serum trace elements level and neutrophil-related functions (oxidative burst activity, phagocytic activity, serum opsonic activity) were determined. RESULTS In males, no significant differences were seen in any serum trace elements concentrations. In females, serum zinc level was significantly higher in bronchial asthma group than in control. A positive correlation was seen between serum concentration of zinc and serum opsonic activity in both genders. CONCLUSIONS In female asthmatics, increase of oxidative stress was suggested to be caused by superoxide dismutase pathway (elimination system of reactive oxygen species) rather than serum opsonic activity (production system of reactive oxygen species from neutrophils) pathway, as the zinc concentration in bronchial asthma group was higher than that in control.

Coping behaviors in relation to depressive symptoms and suicidal ideation among middle-aged workers in Japan

BACKGROUND In Japan, the annual number of deaths by suicide markedly increased in 1998 and leveled off at approximately 30,000 per year thereafter. The coping behaviors used to deal with stress may have implications for the prevention of depression and suicidal ideation. This study examined coping behaviors in relation to depression and suicidal ideation. METHODS In this cross-sectional study, a total of 6762 workers (40-60 years of age; 4119 males and 2643 females) completed both the Center for Epidemiologic Studies Depression scale (CES-D) and a questionnaire measuring suicidal ideation. A cut-off score of 19 was used to define probable depression for the CES-D. Stress-coping behaviors were surveyed via an inventory of 14 items that reflected of actual behaviors covering problem-focused, emotion-focused, and avoidant strategies. RESULTS In relation to depression, logistic regression analyses revealed that in both genders, the highest odds ratios (OR) for avoidant coping strategy and the lowest OR was associated with a problem-focused strategy after adjusting for covariates. After making the same adjustments, logistic regression analyses revealed that in both genders, the highest OR were for emotional distraction coping strategies in relation to suicidal ideation. LIMITATIONS The cross-sectional nature of this study does not allow for causal assumptions regarding the sequential nature of the relationship between coping behaviors and the onset of depressive symptoms or suicidal ideation. CONCLUSIONS These findings indicate that coping behaviors may affect both depressive symptoms and suicidal ideation. Furthermore, gender differences in coping behaviors among middle-aged workers were identified. Additional studies are needed to examine the relationships among coping behaviors, depression and suicidal ideation using a longitudinal design.

No association between dietary patterns and depressive symptoms among a community-dwelling population in Japan

BackgroundStudies of the associations between diet and depression have primarily focused on single nutrients or foods. Recently, dietary patterns representing a combination of foods have attracted more interest than individual nutrient. The objective of this study was to examine the association between dietary patterns and depressive symptoms among a community-dwelling population in Japan.MethodsWe examined the association between dietary patterns and the risk of depression among 791 Japanese community-dwelling individuals. Diet was assessed with a validated brief-type self-administered diet history questionnaire (BDHQ). Dietary patterns from 52 predefined food groups [energy-adjusted food (g/d)] were extracted by principal component analysis. The Center for Epidemiologic Studies Depression Scale (CES-D) with a cut-off point of 16 was used to assess the prevalence of depression.ResultsA total of 97 subjects (12.3%) were classified as having depression. Four dietary patterns were identified: “Healthy”, “Western”, “Bread and confectionery”, and “Alcohol and accompanying” dietary patterns. After adjusting for potential confounders, the dietary patterns were not related to the risk of depression.ConclusionsThe present study failed to find associations between dietary patterns and the risk of depression. However, the interpretation of our results was hampered by the lack of certain data, including employment physical activity and longitudinal observations. Potential associations between dietary patterns and depressive symptoms were not completely ruled out. Future research exploring dietary patterns and depressive symptoms is warranted.

Effects of dehydration on immune functions after a judo practice session.

We investigated the effects of dehydration after a judo practice session on player muscle and immune functions. Subjects included 25 female university judoists. Investigations were performed before and after 2.5 h of regular judo practice. Body composition, serum enzymes (myogenic enzymes, immunoglobulins and complements), neutrophils counts, reactive oxygen species (ROS) production capability, and phagocytic activity (PA) were measured. Subjects were divided into two groups according to level of dehydration after practice (mild dehydration and severe dehydration groups) and results were compared. Creatine kinase was found to increase significantly after practice. In addition, neutrophil count also increased significantly after practice in both groups. The changing ratios of IgA, IgG and C3 observed in the mild dehydration group were significantly higher than those in the severe dehydration group. In the severe dehydration group, post-practice PA/neutrophil had decreased significantly. Significant positive correlations were found between severity of dehydration and changing ratios of IgA, IgG, IgM, C3, C4 and ROS production capabilities, whereas no significant association was seen with PA and/or serum SOD activity. These results suggest that dehydration resulted in immunosuppression, including decreased neutrophil function.

Sex-specific effects of subjective memory complaints with respect to cognitive impairment or depressive symptoms

The aim of this study was to investigate the association between subjective memory complaints (SMC) and sex.

The influence of blood glucose on neutrophil function in individuals without diabetes.

We assessed the association of neutrophil function with glycated hemoglobin (HbA1c) levels in a Japanese general population. Participants were 809 males and females who were over 20 years old living in the Iwaki region in Aomori Prefecture located in northern Japan. Lifestyle parameters (smoking, alcohol consumption, and exercise habits), HbA1c and neutrophil function such as reactive oxygen species (ROS) production capability and phagocytic activity (PA) were measured. ROS production capability was measured before and after phagocytic stimulus to obtain basal ROS production and stimulated ROS production. Level of HbA1c had a positive correlation with basal ROS production (p=0.053), a negative correlation with stimulated ROS production (p=0.072) and PA (p=0.059) only in post-menopausal groups, and not in pre-menopausal groups. However, there were no correlations between levels of HbA1c and neutrophil functions in male. In conclusion, in the present study, despite the presence of diabetes, chronic hyperglycemia was found to cause an increase in daily basal ROS production of neutrophils, and increased susceptibility to infection caused by reduced neutrophilic reaction in females in their menopause. Therefore, from the oxidative point of view, strict glycemic control is necessary to prevent post-menopausal females from developing diabetic complications in spite of the presence of diabetes.

Influence of a 3-month training program on muscular damage and neutrophil function in male university freshman judoists.

We studied the effects of a high intensity and high frequency 3-month training program on muscle damage and neutrophil function in male judoists. The study included 15 male judoists who started intensive judo training program after a 6-month break. Creatine kinase (CK), neutrophil counts and reactive oxygen species (ROS) production capability as well as phagocytic activity (PA) of neutrophils were measured at 2 stages; entering university (pre-training) and after 3-month training (post-training). At both points, we investigated parameters three times: just before, immediately after and 24 h after a 2-h practice session. Practice-mediated change in CK was lower at post-training than at pre-training. Neutrophil count significantly increased after 2-h practice but recovered 24 h later whereas it showed no subsequent and further increased at 24 h post-practice. Although neutrophil ROS production capability and PA both decreased (breakdown) after practice session, ROS production capability increased and PA decreased (well-adapted) at the post-training. Long-term training strengthened muscular function and improved neutrophil reaction against practice-mediated stress.

Effects of soccer matches on neutrophil and lymphocyte functions in female university soccer players

In this study, changes in physical fatigue and biological functions of Japanese female soccer players were investigated by determining changes in neutrophil and lymphocyte functions. Study subjects included 18 female soccer players. Body composition, serum myogenic enzymes, neutrophil function, including reactive oxygen species (ROS) production capability, phagocytic activity (PA) and serum opsonic activity, as well as lymphocyte subpopulation were measured before and after a soccer match. Levels of myogenic enzymes (AST, ALT, CK and LDH) and immunoglobulins (IgG and IgA) and complements (C3) increased significantly after the match. In addition, leukocyte, neutrophils and lymphocyte counts increased whereas total PA decreased significantly. The number of T and Th1 cells (subsets of T helper cells) decreased whereas Th2 increased significantly. In addition, the number of B cells increased and NK cells decreased significantly after the match. The match was found to result in degenerative changes in and damage to athlete muscle tissues together with damage- and change-mediated stress. These data also suggest a post-match accelerated inflammatory reaction and potential immunosuppression as indicated by reductions in neutrophil PA and lymphocyte functions.

Relationship Between Dietary Patterns and Cognitive Function in a Community-Dwelling Population in Japan

The purpose of this study was to clarify the association between dietary patterns and cognitive function in a community-dwelling population in Japan. A total of 388 volunteers (60 years and older) who participated in the Iwaki Health Promotion Project 2011 were recruited. Diet was assessed with a validated, self-administered brief-type diet history questionnaire. Dietary patterns were extracted from 52 predefined food groups by principal component analysis. The Mini-Mental State Examination was also used to measure global cognitive status. Three dietary patterns were identified as follows: “Healthy,” “Noodle,” and “Alcohol and accompaniment.” Compared with the low tertile of the “Alcohol and accompaniment” pattern, only the middle tertile was independently related to an increased risk of poor cognitive function. In conclusions, present study failed to substantiate dose-dependent associations between dietary patterns and the risk of poor cognitive function. Further studies with longitudinal observations are warranted.

Changes in neutrophil functions during a 10-month soccer season and their effects on the physical condition of professional Japanese soccer players

We examined changes in neutrophil function of soccer players over a 10-month period and determined its effectiveness as an index for athlete physical condition. Subjects included 21 male professional Japanese soccer players. Data on body composition, myogenic enzymes and neutrophil function were obtained before and after 2 h of training at 3 investigation points: one week before opening season, at season mid-point, and one week before the last game of the season. As a result, change ratios of myogenic enzyme levels before and after the 2-hr training session at the third investigation point were significantly higher compared to the two other points. Reactive oxygen species production and phagocytic activity significantly increased after 2-hr training session at point 1, although the extent of the increase became smaller over time and ROS production capability decreased significantly by point 3 assessment. Fatigue, especially muscle fatigue, chronically accumulated along with a gradual decrease in neutrophil immune function over the 10-month season. Therefore, determination of neutrophil function can be used as a useful index to assess and understand an athletes physical condition.