Association between sleep duration and a new onset of nonalcoholic fatty liver disease.

Objective A short sleep duration is associated with non-alcoholic fatty liver disease (NAFLD). However, the causal relationship between a short sleep duration and the onset of NAFLD remains unknown because of the lack of any longitudinal studies. Therefore, we evaluated the association between sleep duration and the onset of NAFLD. Methods We evaluated health checkup data for 1,862 NAFLD-free Japanese adults aged 33-86 years at baseline and followed those individuals for a median of 41 months. Hepatic steatosis was examined using ultrasonography (US). The Cox proportional hazards model was used to evaluate the association between sleep duration and NAFLD onset. Results Among the 1,862 participants, 483 (25.9%) developed NAFLD. The proportion of women who developed NAFLD was the highest in the group with a sleep duration of <6 hours and lowest in the group with a sleep duration of 7 to <8 hours. The multivariable-adjusted hazard ratio (95% confidence interval) for the onset of NAFLD in women with a sleep duration <6 hours compared with those with a sleep duration of 7 to <8 hours was 1.55 (1.09-2.20; p=0.02). Conclusions In women, a short sleep duration was independently associated with the onset of NAFLD, thus suggesting that an adequate sleep duration can be a promising preventive factor for the onset of NAFLD in women.

Association between equol production and metabolic syndrome in Japanese women in their 50s-60s.

OBJECTIVE: Equol is an active metabolite of soy isoflavone. As a phytoestrogen, equol has the potential to prevent metabolic disorders such as hyperglycemia, hyperlipidemia, and obesity. This study aimed to determine the association between equol production and metabolic syndrome (METS) in postmenopausal women. METHODS: This cross-sectional study included 1,345 women aged 50 to 69 years who underwent health checkups from February 2018 to November 2021 at four health centers in Fukushima, Japan. Equol producers were defined as those with a urinary equol concentration of 1.0 µM or more. METS was defined based on Japanese diagnostic criteria including abdominal obesity, atherogenic dyslipidemia, elevated blood pressure, and glucose intolerance. The association between equol production and METS was estimated by logistic regression analysis, with adjustments for age, exercise, physical activity, and fast walking. RESULTS: Of the 1,345 women, 378 (28.1%) were equol producers. The proportion of women who had METS (6.6% vs 10.9%) was significantly lower in the equol-producing group than in the nonproducing group. Multivariable logistic regression analysis revealed that equol production was significantly associated with METS (odds ratio, 0.60; 95% CI, 0.38-0.95). CONCLUSIONS: Equol production was associated with a lower prevalence of METS among women aged 50 to 69 years.