Previous studies have indicated that improvement in sleep duration might correlate with better cognition. We aimed to examine the associations between changes in sleep duration and cognitive function. A change from short sleep duration (SSD) to moderate sleep duration (MSD) was associated with better global cognition scores (β=0.54, P <0.01). A change from SSD to long sleep duration (LSD) (β=-0.94, P <0.001) or a change from LSD to SSD (β=-1.38, P <0.01) was associated with lower global cognition. For individuals with MSD, a≥2 h increase (β=-0.89, P <0.001) or decrease (β=-0.70, P <0.001) in sleep duration was associated with lower global cognition. For short sleepers, improvement in sleep duration correlated with better cognition. For long sleepers, there was no need to reduce sleep duration. Excessive changes or deviation from the moderate duration was associated with lower cognition. A total of 10325 individuals aged 45 and older from the China Health and Retirement Longitudinal Study (CHARLS) were included. Self-reported nocturnal sleep duration and cognitive function were assessed in the three waves of CHARLS from 2011 to 2015. Cognitive function was assessed by a global cognition score, which included episodic memory, visuospatial abilities, calculation, orientation and attention.

Despite abundant evidence linking dyslipidaemia to an increased risk of hyperuricaemia, the exact association between each component of dyslipidaemia and hyperuricaemia remains controversial. Thus,...

Background: Long-term exposure to air pollution has been found to contribute to the development of cognitive decline. Our study aimed to assess the association between various air pollutants and cognitive impairment and dementia. Additionally, explore the modification effects of lifestyle and genetic predisposition. Methods: The exposure levels to various air pollutants, including particulate matter (PM) with diameters ≤ 2.5 (PM_2.5), ≤ 10 (PM₁₀), and between 2.5 and 10 μm (PM_2.5−10) and nitrogen oxides (NO and NO₂) were identified. An air pollution score (APS) was calculated to evaluate the combined exposure to these five air pollutants. A genetic risk estimate and healthy lifestyle score (HLS) were also generated. The Cox regression model adjusted by potential confounders was adopted to access the association between pollution exposure and cognitive decline, and several sensitivity analyses were additionally conducted to test the robustness. Results: The combined exposure to air pollutants was associated with an increased risk of incident cognitive decline. Compared with the low exposure group, the hazard ratio (HR) and 95% confidence interval (CI) for all-cause dementia, Alzheimer’s dementia, vascular dementia, and mild cognitive impairment (MCI) in those exposed to the highest levels of air pollutants were respectively 1.07 (95% CI: 1.04 to 1.09), 1.08 (95% CI: 1.04 to 1.12), 1.07 (95% CI: 1.02 to 1.13), and 1.19 (95% CI: 1.12 to 1.27). However, the modification effects from genetic predisposition were not widely observed, while on the contrary for the healthy lifestyle. Our findings were proven to be reliable and robust based on the results of sensitivity analyses. Conclusions: Exposure to air pollution was found to be a significant contributing factor to cognitive impairment and dementia, and this association was not easily modified by an individual’s genetic predisposition. However, adopting a healthy lifestyle may help to manage the risk of cognitive decline related to air pollution.

Objectives This study aimed to examine the urban–rural disparity in health-related quality of life (HRQoL) of the Chinese elderly and to explore the mediating roles of socioeconomic status (SES) and frequency of contact with children in the relationship between urban/rural areas and HRQoL. Methods This cross-sectional study used data from China Health and Retirement Longitudinal Study for 2015–2016, involving 12 369 Chinese aged 45 years and over. HRQoL of respondents was measured by three-level EuroQol five dimensions (EQ-5D-3L). SES, based on principal components analysis, was combined by the individual possessions of durable consumer goods and houses. Frequency of contact with children was derived from the responses to whether they live with children and how often they contact with them. Mediation analyses were performed to examine the mediating effects of SES and frequency of contact in the relationship between urban/rural areas and HRQoL. Results Urban respondents had higher scores of HRQoL than rural respondents (p<0.05). As SES and frequency of contact with children increased, the scores of HRQoL of the elderly went up as well. Mediation analyses proved the possible mediating effects of SES and frequency of contact in the relationship between urban/rural areas and HRQoL (0.0713 and 0.0064). The indirect effects induced by SES and frequency of contact were 65.45% and 5.90%, respectively. Conclusions There was a significant difference in HRQoL between urban and rural middle-aged and elderly participants, which was partially mediated by urban–rural disparities in SES and frequency of contact with children. Higher SES and frequency of contact with children contributed to higher health status in the Chinese elderly.