Correlation Analysis Of Sleep Quality And Cognitive Function Among The Hefei Rural Population In Anhui Province

Objective Mounting evidence revealed a potential connection between sleep quality and cognitive function in elderly people. However, less consistent conclusions had been achieved among many studies of association between insomnia as well as other sleep problems including sleep-disordered breathing and circadian rhythm dysfunction and cognitive impairment. Furthermore, there had been little evidence about this topic in Chinese people. Therefore, we utilized the epidemiology data based on this population-based study and tried to investigate the association between sleep quality and cognitive function among the Hefei rural population in Anhui Province.Method An epidemiological survey was conducted in May,2014 among rural areas in Hefei, Anhui Province. During the survey, the Pittsburgh sleep quality index (PSQI) and Mini-mental state examination (MMSE) were administered to all participants in order to evaluate the sleep quality and cognitive function, respectively. Meanwhile, we also collected several other factors which are associated with sleep quality and cognitive function such as marital status, educational level, smoking status, physical activity, blood pressure, fasting blood-glucose, lipids (triglyceride, low density lipoprotein, high-density lipoprotein, and total cholesterol), blood urea nitrogen, uric acid, creatinine, BMI, depression and nutritional status like albumin. The multiple linear regression analysis was conducted to determine the independent association between PSQI global scores and MMSE scores. Result A total of 777 participants who have completed all the procedures were included in our cross-sectional analyses. (1) Higher PSQI global scores were associated with older age, higher BMI, higher proportion of illiteracy and higher concentrations of blood urea nitrogen (P<0.05). A similar trend was also observed in terms of the proportion of hypertension, depression as well as total cholesterol, but the differences were not statistically significant (P>0.05). Meanwhile, as the PSQI global scores increased, participants had a significantly increased concentration of high density lipoprotein; (2) Results from multiple linear regression analysis adjusted for age, sex, educational level, marital status, blood pressure, fasting blood glucose, lipids, albumin, uric acid, blood urea nitrogen, creatinine, depression, body mass index, smoking status, physical activity and the past medical history showed that the average MMSE scores in the third tertile of PSQI global scores (23.3 ± 5.3, P<0.001) decreased significantly compared with participants in the first tertile (25.5 ± 4.7); (3) The sex-specific analyses showed that lower MMSE scores were significantly associated with increased PSQI global scores in the female participants (β=-0.14, SE=0.05, P=0.004), however the association was non-significant in the male participants (P for interaction=0.093); (4) The age-specific analyses also showed that the negative correlation between PSQI global scores and MMSE scores was only significant among participants older than 60 years (β=-0.19, SE=0.06, P=0.002) but not for participants younger than 60 years (P for interaction=0.026).Conclusion In our cross-sectional study, lower MMSE scores were significantly associated with the increased PSQI global scores in a dose-dependent fashion with the association being only significant in the female participants and participants older than 60 years. Our results showed that poor sleep quality may have a bad effect on cognitive function among the Hefei rural population in Anhui Province and the large prospective cohort studies are worthy to confirm our findings.