Association of LIfestyle for BRAin health risk score (LIBRA) and genetic susceptibility with incident dementia and cognitive decline

Lifestyle and cognition: Separating the effects of average lifestyle and lifestyle changes based on the LIBRA score

BACKGROUND

The LIfestyle for BRAin Health (LIBRA) score, consisting of twelve factors, highlights individuals' potential for dementia risk reduction through lifestyle. The LIBRA score includes modifiable protective factors such as low to moderate alcohol consumption, and risk factors such as hypertension.

OBJECTIVE

We studied whether LIBRA scores are longitudinally associated with cognition, and to what extent this is due to between-person differences or within-person changes in LIBRA scores.

METHODS

Individuals were included from four Dutch community-based cohorts: Doetinchem Cohort Study (DCS; n = 4770), Maastricht Aging Study (MAAS; n = 1295), Longitudinal Aging Study Amsterdam (LASA; n = 2391) and the Rotterdam Study (RS; n = 5205). The number of available LIBRA components (range 7-11) and timepoints (range 3-9) differed per cohort. Outcomes were standardized processing speed (LDST), memory (15-word delayed recall of the verbal learning test (VLT)) and verbal fluency. Hybrid mixed models were fit for the association of 1) mean LIBRA score and 2) change in LIBRA between subsequent timepoints. Models were adjusted for age, sex, education and learning effects. Interactions of the mean LIBRA score with age, and change in LIBRA score with age were tested in two separate models.

RESULTS

Higher (i.e., unhealthier) mean LIBRA scores were associated with worse cognitive speed (lower LDST z-score per 1-point higher LIBRA, range between cohorts: 0.039 - 0.0587), memory (VLT, 0.026 - 0.035), and fluency (0.020 - 0.033). Associations of mean LIBRA scores with cognitive function were stronger with older age (LDST: significant age-interaction, 2 out of 4 cohorts; VLT and fluency: 1 out of 4 cohorts). Relative to 65-year-old individuals with a mean LIBRA score at the 50th percentile, individuals at the 90th percentile of the LIBRA score showed an estimated 1.9-3.2 years more advanced cognitive ageing for LDST, 1.9 - 5.3 years for VLT and 1.4 - 1.7 years for fluency. Within-person change in LIBRA showed no consistent associations with cognitive decline.

CONCLUSIONS

An individual's mean LIBRA score, but not their change in LIBRA score over time, was longitudinally associated with cognitive functioning. In the general population, the investigated version of the LIBRA score is possibly not suitable to capture how cognition (as a proxy for dementia risk) changes with improvements in lifestyle.

Measures of retinal health successfully capture risk for Alzheimer's disease and related dementias at midlife

BACKGROUND

Identification of at-risk individuals who would benefit from early intervention for Alzheimer's disease and related dementias (ADRD) is critical as new treatments are developed. Measures of retinal health could offer accessible and low-cost indication of pre-morbid disease risk, but their association with ADRD risk is unknown.

OBJECTIVE

To determine whether midlife retinal neuronal and microvascular measures are associated with ADRD risk-index scores and individual domains of ADRD risk.

METHODS

Data were from the Dunedin Multidisciplinary Health and Development Study, a population-representative longitudinal New Zealand-based birth cohort study. 94.1% (N = 938) of living Study members were seen at age 45 (2017-2019). Retinal neuronal (retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL)) and microvascular (arterioles and venules) measures were used as predictors. Outcome measures were four top ADRD risk indexes (CAIDE, LIBRA, Lancet, and ADU-ADRI), and a comprehensive midlife ADRD risk index, the DunedinARB.

RESULTS

Poorer retinal microvascular health (narrower arterioles and wider venules) was associated with greater ADRD risk (βs = 0.16-0.31; ps < 0.001). Thinner RNFL was modestly associated with higher ADRD risk (βs = 0.05-0.08; ps = 0.02-0.13). Follow-up tests of distinct domains of ADRD risk indicated that while RNFL associations reflected cardiometabolic risk only, microvascular measures were associated with diverse ADRD risk factors.

CONCLUSIONS

Measures of retinal health, particularly microvascular measures, successfully capture ADRD risk across several domains of known risk factors, even at the young midlife age of 45 years. Retinal microvascular imaging may be an accessible, scalable, and relatively low-cost method of assessing ADRD risk among middle-aged adults.

Joint effect of polysocial risk score, lifestyle and genetic susceptibility with the risk of dementia: A prospective cohort study

OBJECTIVES

The comprehensive impact of polysocial risk score (PsRS)-encompassing multiple social determinants of health (SDoHs) with genetic and lifestyle factors on dementia incidence remains to be elucidated.

STUDY DESIGN

This study aimed to clear the associations between PsRS and dementia incidence and evaluated how genetic and lifestyle factors modified these associations in the UK Biobank cohort.

METHODS

The detailed prospective study involved over 500,000 participants when recruited in 2006-2010. The PsRS was calculated by 12 SDoHs across psychosocial factors, socioeconomic status, and neighborhood and living environment. A healthy lifestyle score was constructed from physical activities, alcohol consumption, smoking status, and diet. A genetic risk score (GRS) was computed via genotype data from UK Biobank. The Cox proportional hazards model was used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for the association between PsRS, lifestyle factors, GRS and dementia.

RESULTS

Results showed the participants with intermediate (HR = 1.32, 95%CI: 1.20-1.45) and high PsRS (HR = 2.10, 95 % CI: 1.91-2.32) were significantly associated with an increased risk of dementia compared with those with a low PsRS. Then, compared with participants with low PsRS and favorable lifestyle/low GRS, high PsRS and unfavorable lifestyle/high GRS had the highest risk of dementia (HR = 3.11,95%CI: 2.63-3.68)/(HR = 3.56, 95%CI: 2.62-4.85).

CONCLUSIONS

Both high PsRS and GRS were significantly associated with higher dementia risk. A favorable lifestyle could reduce dementia incidence regardless of high PsRS or GRS. Additionally, focusing on the intervention of SDoHs would be positive in preventing dementia.

Menopausal hormone therapy is associated with worse levels of Alzheimer's disease biomarkers in APOE ε4-carrying women: An observational study

INTRODUCTION

Menopausal hormone therapy (MHT), along with the apolipoprotein E (APOE) ε4 allele, has been suggested as a possible risk factor for Alzheimer's disease (AD). However, the relationship between MHT and cerebrospinal fluid (CSF) biomarkers is unknown: we investigated this association, and whether APOE ε4 carrier status moderates it.

METHODS

In an observational study of 136 cognitively unimpaired female participants (Mage = 66.0; standard deviation = 6.3), we examined whether MHT use alone or in interaction with APOE ε4 carrier status was associated with CSF levels of phosphorylated tau (p-tau), amyloid beta (Aβ)40, Aβ42, p-tau/Aβ42, and Aβ42/40 ratios.

RESULTS

Significant interactions were found between APOE ε4 and MHT use for CSF biomarkers. APOE ε4 carriers who were MHT users showed worse levels of CSF p-tau/Aβ42 and Aβ42/40 ratios than all other users and non-users.

DISCUSSION

The presence of both APOE ε4 and MHT may be associated with elevated amyloid deposition and AD pathology in this sample of participants who demonstrated high familial AD risk.

HIGHLIGHTS

Significant interactions were found between apolipoprotein E (APOE) ε4 and menopausal hormone therapy (MHT) use for cerebrospinal fluid (CSF) phosphorylated tau (p-tau)/amyloid beta (Aβ)42 and Aβ42/40 ratios. APOE ε4 carriers who were MHT users showed worse levels of CSF biomarkers than non-users and non-carriers, both users and non-users. Younger age at MHT initiation was associated with worse levels of the p-tau/Aβ42 and Aβ42/40 ratios in carriers only. The presence of both APOE ε4 carriage and MHT use may be associated with elevated amyloid deposition and AD pathology. Further studies with larger sample sizes are necessary to confirm the differences observed in the current study.