Effects of body compositions on the associations between ferritin and diabetes parameters among Japanese community dwellers.

BACKGROUND: Ferritin is associated with an increased prevalence of diabetes mellitus. Moreover, the ferritin levels differ across the body compositions. Although there were studies reporting the association of ferritin and diabetes, the alteration in ferritin-diabetes association by body composition differences is rarely explained. Thus, the aim of this study is to identify the effects of body compositions on the association between ferritin and diabetes parameters among the Japanese population. METHODS: This study analyzed the data of a cross-sectional study with 1065 subjects aged over 19 years in the Iwaki area, Japan. Independent variables were ferritin and body compositions, while dependent variables were blood sugar, HbA1c, and diabetes mellitus. Correlations between serum ferritin and blood sugar and HbA1c were analyzed using Spearman's Rank Correlation. Multivariate linear or logistic regressions were used to investigate the effects of body compositions (body fat percentage, muscle mass, or visceral fat level) on the ferritin-diabetes associations by adjusting the confounders. RESULTS: There were significant positive correlations between ferritin and blood sugar in both sexes (p < 0.05), while a significant correlation between ferritin and HbA1c was found only in females (p < 0.001). Higher ferritin was significantly associated with an increase in blood sugar in individuals with normal body fat percentage (lowest vs. highest quartile group, coefficient=5.07, 95 % confidence intervals [CI]: 1.48-8.65), normal visceral fat level (lowest vs. highest quartile group, coefficient=4.84, 95 % CI: 1.74-7.94), and very high muscle mass (lowest vs. highest quartile group, coefficient=14.14, 95 % CI: 5.00-23.29). CONCLUSIONS: By our study findings, individuals' body composition notably influenced the associations of serum ferritin and diabetes parameters, and the association was attenuated in obese individuals.

Association of locomotive activity with sleep latency and cognitive function of elderly patients with cardiovascular disease in the maintenance phase of cardiac rehabilitation.

BACKGROUND: Because of the advanced age of patients with cardiovascular disease (CVD), prevention of sleep disorder and dementia is a priority for cardiac rehabilitation (CR) during their long-term care. This study aimed to investigate the association of physical activity with sleep quality and cognitive function in elderly patients with CVD in the CR maintenance phase. METHODS: We conducted a multicenter study through the Clinical Exercise Physiology Association Japan network, which included 102 elderly patients (mean age, 74±7.4 years) with CVD undergoing phase III CR at 6 institutions. Physical activity was assessed using a triaxial accelerometer for 7 consecutive days and was classified as locomotive and household activities. Physical fitness was assessed via 6-min walking distance (6MD), hand grip power, 10-m walking speed, one leg standing time with eyes open, and 10 times sit-to-stand tests. Sleep quality and cognitive function were evaluated using the Pittsburgh sleep quality index (PSQI) and mini-mental state examination (MMSE) scores, respectively. RESULTS: The patients performed 5506.8±3743.6 steps/day and scored 5.8±3.5 points in the PSQI and 28.4±1.7 points in the MMSE. Sleep latency and MMSE scores correlated with locomotive activity, but not with household activity. Locomotive activity and 6MD were independent predictors of sleep latency and MMSE score, respectively. When patients with heart failure were excluded, the relationship between sleep latency and locomotive activity was preserved, but the relationship between exercise tolerance and cognitive function disappeared. CONCLUSION: Locomotive activity and exercise tolerance are associated with sleep latency and cognitive function in elderly patients with CVD continuing phase III CR. However, in this study, the relationship between exercise tolerance and cognitive function was offset by the presence of heart failure.