Favourable Lifestyle Protects Cognitive Function in Older Adults With High Genetic Risk of Obesity: A Prospective Cohort Study.

The relationship between body mass index (BMI) and cognitive impairment remains controversial, especially in older people. This study aims to confirm the association of phenotypic and genetic obesity with cognitive impairment and the benefits of adhering to a healthy lifestyle. This prospective study included 10,798 participants (aged ≥ 50 years) with normal cognitive function from the Health and Retirement Study in the United States. Participants were divided into low (lowest quintile), intermediate (quintiles 2-4), and high (highest quintile) groups according to their polygenic risk score (PRS) for BMI. The risk of cognitive impairment was estimated using Cox proportional hazard models. Higher PRS for BMI was associated with an increased risk, whereas phenotypic obesity was related to a decreased risk of cognitive impairment. Never smoking, moderate drinking, and active physical activity were considered favourable and associated with a lower risk of cognitive impairment compared with current smoking, never drinking, and inactive, respectively. A favourable lifestyle was associated with a low risk of cognitive impairment, even in subjects with low BMI and high PRS for BMI. This study suggest that regardless of obesity status, including phenotypic and genetic, adhering to a favourable lifestyle is beneficial to cognitive function.

Associations of Parity With Change in Global Cognition and Incident Cognitive Impairment in Older Women.

Background: The evidence of the association between parity and risk of mild cognitive impairment (MCI) or dementia is mixed, and the relationship between parity and longitudinal cognitive changes is less clear. We investigated these issues in a large population of older women who were carefully monitored for development of MCI and probable dementia. Methods: Using the Women's Health Initiative Memory Study, 7,100 postmenopausal women (mean age 70.1 ± 3.8 years) with information on baseline parity (defined as the number of term pregnancies), measures of global cognition (Modified Mini-Mental State Examination score) from 1996-2007, and cognitive impairment (centrally adjudicated diagnoses of MCI and dementia) from 1996-2016 were included. Multivariable linear mixed-effects models were used to analyze the rate of changes in global cognition. Cox regression models were used to evaluate the risk of MCI/dementia across parity groups. Results: Over an average of 10.5 years, 465 new cases of MCI/dementia were identified. Compared with nulliparous women, those with a parity of 1-3 and ≥4 had a lower MCI/dementia risk. The HRs were 0.75 (0.56-0.99) and 0.71 (0.53-0.96), respectively (P < 0.01). Similarly, a parity of 1-3 and ≥4 was related to slower cognitive decline (ß = 0.164, 0.292, respectively, P < 0.05). Conclusion: Higher parity attenuated the future risk for MCI/dementia and slowed the rates of cognitive decline in elderly women. Future studies are needed to determine how parity affects late-life cognitive function in women.

Long-Term Increase in Cholesterol Is Associated With Better Cognitive Function: Evidence From a Longitudinal Study.

Background: Higher visit-to-visit cholesterol has been associated with cognitive decline. However, the association between long-term increase or decrease in cholesterol and cognitive decline remains unclear. Methods: A total of 4,915 participants aged ≥45 years with normal cognition in baseline were included. The participants were divided into four groups, namely low-low, low-high, high-low, and high-high, according to the diagnostic thresholds of total cholesterol (TC), non-high-density lipoprotein cholesterol (NHDL-C), low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol (HDL-C) after 4 years of follow-up. Cognitive function was assessed by episodic memory and mental intactness. Binary logistic regression was used to analyse the association of cholesterol variation with cognitive decline. Results: Among the participants, 979 (19.9%) experienced global cognitive decline. The odds ratio (OR) of global cognitive and memory function decline were remarkably lower in participants in the low-high NHDL-C group than those in the low-low group [OR and 95% confidence interval (CI): 0.50 [0.26-0.95] for global cognitive decline, 0.45 [0.25-0.82] for memory function decline]. The lower OR was also significant in females (OR [95% CI]: 0.38 [0.17-0.87] for global cognitive decline; 0.44 [0.19-0.97] for memory function decline) and participants without cardiovascular disease (OR [95% CI]: 0.31 [0.11-0.87] for global cognitive decline; 0.34 [0.14-0.83] for memory function decline). The increases in other cholesterol were also negatively associated with the risk of cognitive decline although not significantly. Conclusions: A longitudinal increase in NHDL-C may be protective for cognition in females or individuals without cardiovascular disease.

Variability in Cardiometabolic and Inflammatory Parameters and Cognitive Decline.

INTRODUCTION: The relationship between variability in cardiometabolic and inflammatory parameters and cognitive changes is unknown. This study investigates the association of visit-to-visit variability in BMI, mean arterial pressure, total cholesterol, triglycerides, HbA1c, high-sensitivity C-reactive protein, ferritin, and fibrinogen with cognitive decline. METHODS: This population-based cohort study included 2,260 individuals (mean age=63.0 [SD=7.5] years) free of cognitive diseases who underwent ≥3 clinical measurements from 2004 to 2019. Variability was expressed as variability independent of the mean across visits. Participants were divided on the basis of quartiles of variability score, a scoring system generated to explore the composite effect of parameter variability (range=0-24), where 0 points were assigned for Quartile 1, 1 point was assigned for Quartile 2, 2 points were assigned for Quartile 3, and 3 points were assigned for Quartile 4, each for the variability of 8 parameters measured as variability independent of the mean. Linear mixed models evaluated the longitudinal associations with cognitive decline in memory and verbal fluency. All analyses were conducted in 2020-2021. RESULTS: Higher BMI, mean arterial pressure, total cholesterol, HbA1c, and ferritin variability were linearly associated with cognitive decline irrespective of their mean values. In addition, participants in the highest quartile of variability score had a significantly worse cognitive decline rate in memory (-0.0224 points/year, 95% CI= -0.0319, -0.0129) and verbal fluency (-0.0088 points/year, 95% CI= -0.0168, -0.0008) than those in the lowest quartile. CONCLUSIONS: A higher variability in cardiometabolic and inflammatory parameters was significantly associated with cognitive decline. Stabilizing these parameters may serve as a target to preserve cognitive functioning.

Depression as a Mediator of the Association Between Wealth Status and Risk of Cognitive Impairment and Dementia: A Longitudinal Population-Based Cohort Study.

BACKGROUND: Wealth and income are potential modifiable risk factors for dementia, but whether wealth status, which is composed of a combination of debt and poverty, and assessed by wealth and income, is associated with cognitive impairment among elderly adults remains unknown. OBJECTIVE: To examine the associations of different combinations of debt and poverty with the incidence of dementia and cognitive impairment without dementia (CIND) and to evaluate the mediating role of depression in these relationships. METHODS: We included 15,565 participants aged 51 years or older from the Health and Retirement Study (1992-2012) who were free of CIND and dementia at baseline. Dementia and CIND were assessed using either the modified Telephone Interview for Cognitive Status (mTICS) or a proxy assessment. Cox models with time-dependent covariates and mediation analysis were used. RESULTS: During a median of 14.4 years of follow-up, 4,484 participants experienced CIND and 1,774 were diagnosed with dementia. Both debt and poverty were independently associated with increased dementia and CIND risks, and the risks were augmented when both debt and poverty were present together (the hazard ratios [95% confidence intervals] were 1.35 [1.08-1.70] and 1.96 [1.48-2.60] for CIND and dementia, respectively). The associations between different wealth statuses and cognition were partially (mediation ratio range: 11.8-29.7%) mediated by depression. CONCLUSION: Debt and poverty were associated with an increased risk of dementia and CIND, and these associations were partially mediated by depression. Alleviating poverty and debt may be effective for improving mental health and therefore curbing the risk of cognitive impairment and dementia.

Diabetes Treatment Is Associated With Better Cognitive Function: The Age Disparity.

Background: Diabetes mellitus (DM) is a recognised risk factor for cognitive dysfunction. The purpose of this study was to explore the relationship between active treatment for DM and cognitive function in middle-aged (< 60 years) and older adults (≥60 years), respectively. Methods: A total of 13,691 participants (58.55 ± 9.64 years, 47.40% of men) from the Chinese Health and Retirement Longitudinal Study (CHARLS) were included. The participants were classified into three groups according to whether or not they have diabetes and to their diabetes treatment status: diabetes-free, treated-diabetes and untreated-diabetes, in which the diabetes-free group was regarded as reference specially. Cognitive function was assessed by two interview-based measurements for mental intactness and episodic memory. Results: Compared with the participants in the diabetes-free group, the older participants in the treated-diabetes group had better performance in terms of mental intactness (ß = 0.37, 95% CI = 0.04-0.70). No significant association was observed in the middle-aged participants. In the subgroup analyses, the lower cognitive score was only observed in people without depression, who had never smoked and drunk, and with a normal weight (body mass index: 18.5-23.9 kg/m2). Conclusion: The cognitive function of actively treated diabetic patients was better than that of patients without diabetes, but the improvement was significant only in elderly people. Depression, smoking, drinking, and an abnormal weight may attenuate this effect.