Menopausal age represents the endpoint of the entire reproductive cycle of women, and it is a biological marker that indicates the overall health and aging status of women. Flavonoids are the most common polyphenolic compounds in the daily diet, and their intake is related to reduced risks of certain diseases. Our study aimed to analyze the relationships between the intake of flavonoids and menopausal age. We selected 29,940 participants from NHANES database from 2007-2008, 2009-2010 and 2017-2018. A total of 680 participants were included in our analysis after screening. Multiple logistic regression was used to explore the association between dietary flavonoid subclasses intake and menopausal delay (≥ 55 years old). RCS plots were generated to reveal the nonlinear relationships between the subclasses of flavonoids intake and menopausal age. According to the adjusted multiple factor logistic regression analysis, the top quartile intake (compared with bottom intake) of anthocyanidins was positively associated with delayed menopause (OR = 4.123; 95% CI: 1.130, 15.041; p trend = 0.036), whereas the moderate intake of flavonols was negatively associated with delayed menopause (Q2 vs. Q1, OR = 0.081 (95% CI: 0.025, 0.261), p trend = 0.001; Q3 vs. Q1, OR = 0.271 (95% CI: 0.093, 0.791), p trend = 0.023). The RCS revealed that non-linear association was observed between the intake of isoflavones, flavan-3-ols, flavonols and later menopause (p-value for non-linearity < 0.05). Our findings suggest that specific dietary flavonoids intake may have potential roles in regulating menopausal timing.

Cognitive decline is a public health problem for the world’s ageing population. This study was to evaluate the relationships between serum Fe, blood Pb, Cd, Hg, Se and Mn and cognitive decline in elderly Americans. Data of this cross-sectional study were extracted from the National Health and Nutritional Examination Survey (NHANES 2011–2014). Cognitive performance was measured by the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD), Animal Fluency and Digit Symbol Substitution Test (DSST) tests. Weighted univariable and multivariate logistic regression analyses were used to assess the associations between six trace elements and low cognitive performance. Subgroup analyses based on diabetes and hypertension history were further assessed the associations. A total of 2002 adults over 60 years old were included. After adjusting covariates, elevated serum Fe levels were associated with the decreased risk of low cognitive performance, especially in the elderly without diabetes history and with hypertension history. High blood Cd levels were associated with the high odds of low cognitive performance in old adults with diabetes and hypertension history. Elevated blood Mn levels were connected with low cognitive performance in old hypertensive people. High blood Pb levels were related to the high odds of low cognitive performance, especially in the elderly without diabetes and hypertension history. High blood Se levels were linked to the decreased risk of low cognitive performance in all the elderly. Appropriate Fe, Se supplementation and Fe-, Se-rich foods intake, while reducing exposure to Pb, Cd and Mn may be beneficial for cognitive function in the elderly.