Sex-specific associations between lipids and cognitive decline in the middle-aged and elderly: a cohort study of Chinese adults

Abstract

Background Studies regarding the lipid-cognition relationship have increasingly gained popularity but have generated much mixed results. To date, few studies have focused on the difference between sexes. Methods This study included 6792 Chinese adults aged over 45 years (women, 48.56%; mean age, 57.28 years), who were free of severe conditions known to affect cognitive function at the baseline (2011). Blood concentrations of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), and triglycerides (TG) were assessed at baseline, and both continuous and categorical values were used in final analyses. Global cognitive functions were assessed by the word recall test and the mental status test in 2011, 2013, and 2015, respectively. We graded participants into three groups according to the cognitive change slopes: no decline (≥ 0), moderate decline (median to 0), and severe decline (< median). Sex-specific associations between blood lipids and cognitive decline were analyzed using ordinal logistic models, adjusting for sociodemographic information, lifestyle behaviors, and health status. Results Higher baseline TC and LDL-C concentrations exhibited no significant association with 5-year cognitive decline in men but were significantly associated with greater 5-year cognitive decline in women [odds ratio (OR) 1.026, 95% confidence interval (CI) 1.003, 1.050; OR 1.026, CI 1.002, 1.051, respectively]. For higher serum HDL-c levels, a significantly protective effect on cognition was observed in men, but a slightly adverse effect was found in women (not significant after Bonferroni correction). TG presented almost no effect on later cognition in either sex. Conclusion Different associations between sexes were observed for the lipid-cognition relationship, and maintaining serum cholesterol levels at an appropriate range may have a positive effect on cognitive health.

Association Between HDL Cholesterol and Incident Cognitive Impairment in Black and White Adults in The Reasons For Geographic and Racial Differences in Stroke Study

“…Few studies have analyzed sex-speci c differences in HDL-C and ICI. The China Health and Retirement Longitudinal Study (CHARLS) investigated ICI in 6,792 Chinese stroke-free adults aged 45 years and older, and paradoxically reported a higher HDL-C level was associated with a higher risk of cognitive decline in women, but a lower risk of cognitive decline in men (12). Among women <60 years of age, the adjusted odds ratio for cognitive decline associated with HDL-C levels of 40-59 mg/dL and ≥60 mg/dL versus<40 HDL-C is a common metric for HDL; however, the cholesterol content of HDL is an inadequate metric for the multifarious functions of HDL (14).…”

Risk Factors, Lifestyle Behaviors, and Vascular Brain Health

“…Risk factors for poor brain health differ in men versus women; in the Kaiser system, midlife hypertension was associated with dementia in women, but not men. 128 Similarly, elevated cholesterol was associated with steeper cognitive decline in women but not men, 129 and higher body mass index was associated with cognitive decline only in women. 130 The greater impact in women could arise from a longer life-expectancy 131 or perhaps greater vulnerability of the brain to vascular risk factors in the postmenopausal state.…”

Associations between pulmonary function and cognitive decline in the middle-aged and older adults: evidence from the China Health and Retirement Longitudinal Study

“…Based on previous studies [6,11,[26][27][28], demographic characteristics included age (years), residence (urban/ rural), marital status (married/divorced/single), education (illiterate/primary school/middle school and above) and health insurance status (yes/no). Lifestyle behaviors including smoking status (current/former/never), alcohol use (current/former/never) and social activity (none/inactive/active) were also taken into consideration.…”