Background: Uric acid (UA) may protect muscle function from oxidative damage due to reactive oxygen species through its powerful antioxidant capacity. However, several studies have demonstrated that hyperuricemia is closely related to systemic inflammation and has oxidant properties effects, both of which may increase the risk of muscle strength loss. The purpose of this study was to examine the association of serum UA concentration with grip strength and leg extension power in adult men. Methods: This study is a cross-sectional survey in which 630 Japanese male employees aged 30 years and older participated. Five hundred and eighty-six subjects participated in the measurement of grip strength, and 355 subjects participated in the measurement of leg extension power. Blood samples were obtained for serum UA analysis. Results: After adjustment for potential confounders, grip strength differed significantly between participants with and those without hyperuricemia (geometric mean and 95% confidence interval [CI]: 40.3 [39.2–41.3] kg vs. 41.9 [41.3–42.5] kg; P = 0.01). In addition, serum UA levels (quartiles) showed an inverted J-shaped curve with grip strength (mean and 95% CI: Q1, 41.6 [40.6–42.6] kg; Q2, 42.2 [41.2–43.2] kg; Q3, 41.8 [40.8–42.8] kg; Q4, 40.4 [39.3–41.4] kg; P for quadratic trend = 0.05). The results in the leg extension power group were similar to those observed in the grip strength group. Conclusion: This population-based cross-sectional study shows for the first time that hyperuricemia is associated with poor muscle strength. Moreover, the results indicate an inverted J-shaped association between serum UA quartiles and muscle strength.

Isoflavones comprise a class of phytoestrogens that resemble human estrogen in chemical structure, and have weak estrogenic effects. Because estrogen modulates sleep duration and quality, we hypothesized that isoflavones would have a beneficial effect on sleep status in a way similar to estrogen. We conducted a cross-sectional study to investigate the relationship between daily isoflavone intake and sleep status in Japanese subjects. Our study included 1076 Japanese adults aged 20-78 years. Daily isoflavone intake was assessed using a brief self-administered diet history questionnaire, and sleep was evaluated using a self-reported questionnaire. The prevalence of regular sleep duration (7–8 h/day) and sufficient sleep quality were 13.3 % and 56.2 %, respectively. After adjusting for potential confounding factors, the odds ratios (95 % CIs) for optimal sleep duration (7–8 h) when higher isoflavone intakes (Q2–Q4) were compared with low isoflavone intake (Q1) were Q2: 0.94 (0.53–1.56); Q3: 1.28 (0.73–2.24); and Q4: 1.84 (1.06–3.18) (p for trend = 0.013). In the final adjusted model, sufficient sleep quality across categories of isoflavone intake was Q1: 1.00 (reference); Q2: 1.30 (0.91–1.84); Q3: 1.48 (1.03–2.12); and Q4: 1.78 (1.22–2.60); (p for trend = 0.002). Higher daily isoflavone intake was positively associated with optimal sleep duration and quality in a Japanese population. This finding suggests that daily isoflavone intake may have a potentially beneficial effect on sleep status.

Sunlight has been reported to have various beneficial effects on human health. Although research indicates an association between sunlight exposure and depressive symptoms, no study has examined it among the older adult population, especially among elderly Chinese women. This cross-sectional study addresses the aforesaid gap by investigating this association in 1,429 Chinese women aged 60 years and older. Information on their sunlight exposure was collected through a self-reported questionnaire. Depressive symptoms were assessed using the Zung Self-Rating Depression Scale (SDS). The logistic regression models revealed that greater exposure to sunlight is associated with a lower prevalence of depressive symptoms. In the final adjusted model, when the short sunlight exposure category (reference) was compared with the medium and long ones, the odds ratios and 95% confidence intervals for the prevalence of depressive symptoms (SDS cutoff ≥ 45) were 0.84 (0.60, 1.19) and 0.62 (0.43, 0.91), respectively (p-value for trend = 0.01). This significant association did not change when the SDS cutoff points were altered to ≥ 40 and ≥ 50. Findings indicate that an increased sunlight exposure duration is associated with a lower prevalence of depressive symptoms in elderly women.

Objectives: Studies have investigated the association between alcohol consumption and muscle mass and muscle disease. However, the relationship between alcohol consumption and muscle strength remains unclear. This study aimed to prospectively investigate the association between alcohol consumption and changes in muscle strength. Methods: This study evaluated 326 Japanese men and women over a 2-year period, assessing alcohol consumption using a brief, self-administered diet-history questionnaire. Muscle strength was assessed using a digital grip dynamometer. Results: In a non-adjusted model, alcohol consumption was positively correlated with a decline in muscle strength (p for trend = 0.002). After adjusting model 1 for age, sex, and body mass index, adjusting model 2 for health status and fully adjusting model 3, there was a significant positive association between alcohol consumption and a decline in muscle strength, and this association showed no change over the 2-year period (p for trend = 0.006). Conclusion: In this Japanese population, high alcohol consumption was associated with a greater decline in muscle strength. Future studies are needed to ascertain whether this relationship is present in other populations.

Purpose: Several studies have investigated the association between physical exercise and depressive symptoms in the elderly population. However, the relationship between components of physical exercise such as frequency, intensity, duration, and depressive symptoms remains unclear. This study was conducted on elderly Chinese women to investigate the association between each component of physical exercise and depressive symptoms and to examine the association between physical exercise patterns and depressive symptoms. Patients and Methods: A total of 1429 Chinese women aged ≥ 60 years were enrolled in this cross-sectional study and provided information on their exercise behaviors through a self-reported questionnaire. Depressive symptoms were assessed using the Zung Self-Rating Depression Scale. Multiple logistic regression analysis was used to estimate adjusted odds ratios (ORs) to measure the association between exercise behaviors and depression. Results: High frequency, moderate intensity, long duration, and exercise habits were significantly associated with lower levels of depressive symptoms. Furthermore, participants with more than one optimal exercise behavior were more likely to have a lower risk of depressive symptoms. These associations were not changed after adjustment for confounding factors. Conclusion: This study shows that exercise behaviors were significantly associated with the risk of developing depression. This finding suggests that keeping an optimal exercise behavior may be associated with a lower risk of depressive symptoms in elderly Chinese women.