Munehiro Matsushita

Body Mass Index and Kidney Stones: A Cohort Study of Japanese Men

BACKGROUND In Japan, the incidence of kidney stones has increased markedly in recent decades. Major causes of kidney stones remain unclear, and limited data are available on the relationship between overweight/obesity and the incidence of kidney stones. We therefore evaluated body mass index (BMI) and the incidence of kidney stones in Japanese men. METHODS Of the workers at a gas company, 5984 males aged 20-40 years underwent a medical examination in 1985 (baseline). This study includes 4074 of the men, who were free of kidney stones at baseline and underwent a second medical examination performed between April 2004 and March 2005. BMI was calculated from measured height and weight in 1985, and men were categorized into tertiles. The development of kidney stones during follow-up was based on self-reports from questionnaires at the second medical examination. RESULTS The average duration of follow-up was 19 years, with 258 participants developing kidney stones during this period. Using the lowest BMI (1st tertile) group as a reference, the hazard ratios (95% confidence intervals [CIs]) for the 2nd and 3rd BMI tertiles were: 1.26 (95% CI, 0.92-1.73) and 1.44 (95% CI, 1.06-1.96), respectively (P for trend = 0.019). After additionally adjusting for potential confounders, such as age, systolic blood pressure, cardiorespiratory fitness, cigarette smoking, and alcohol consumption, the hazard ratios were 1.28 (95% CI, 0.93-1.76) and 1.41 (95% CI, 1.02-1.97), respectively (P for trend = 0.041). CONCLUSIONS These results suggest that increased BMI is a risk factor for kidney stones in Japanese men.

A cross-sectional study on the factors related to cognitive decline in community-dwelling elderly

AIM The aim of this study was to examine the relationship between cognitive decline and physical activity, sitting time, and social participation among elderly people living independently in a local community. METHODS In January 2015, 1,133 independently-living elderly individuals from a local Japanese community completed self-administrated questionnaires. A total of 929 participants completed the questionnaire (valid response rate: 82.0%). A multiple logistic regression analysis was conducted to examine the relationship between cognitive decline, physical activity, sitting time, and social participation. The factors related to cognitive decline were examined using three statistical models: (1) Model 1 was not adjusted for any factors; (2) Model 2 was adjusted for age, education level, smoking status, and drinking status; and (3) Model 3 was adjusted for the covariates in Model 2, plus depression. RESULTS Cognitive decline was observed in 33% of men and 26% of women. The results indicated that decreased social participation was significantly related to cognitive decline in Models 1 and 2. For men, local community activity and political/economic activity were significantly associated with cognitive decline in Models 1 and 2. Among women, physical activity was significantly related to cognitive decline in Model 1. There was also a significant association between social participation and cognitive decline in Models 1 and 2; decreased volunteer activity was significantly related to cognitive decline in all three models. CONCLUSION The results of the present study indicated that attending volunteer activities was significantly related to cognitive decline in women.

Dynapenic Obesity and Prevalence of Type 2 Diabetes in Middle-Aged Japanese Men

BACKGROUND The independent and combined associations of muscle strength and obesity on the prevalence of type 2 diabetes in Japanese men remain unclear. METHODS Hand grip strength was cross-sectionally evaluated between 2011 and 2013 to assess muscle strength in 5039 male workers aged 40 to 64 years. Weight and height were measured, and overweight/obesity was defined as a body mass index ≥25 kg/m(2). The prevalence of type 2 diabetes, defined as fasting plasma glucose ≥126 mg/dL and/or hemoglobin A1c ≥6.5% and/or self-reported physician-diagnosed diabetes, was evaluated. Odds ratios (OR) and 95% confidence intervals (95% CI) for the prevalence of type 2 diabetes were obtained using a logistic regression model. RESULTS In total, 611 participants had type 2 diabetes, and 1763 participants were overweight/obese. After adjustment for covariates, we found an inverse association between muscle strength and the prevalence of type 2 diabetes (P for trend <0.01). In addition, when the analyses were stratified by obesity status, the multivariable-adjusted OR per 2-standard-deviation increase in muscle strength was 0.64 (95% CI, 0.49-0.83) in the overweight/obese group, compared to a weaker relationship in the normal-weight group (OR 0.79 per 2-standard-deviation increase; 95% CI, 0.60-1.06). CONCLUSIONS Dynapenia, an age-related decrease in muscle strength, is associated with increased prevalence of type 2 diabetes, and this relationship is stronger in overweight/obese middle-aged Japanese men than in normal-weight men.