The association of diffusion tensor MRI measures of normal appearing white matter and cognition.

Objective: Median and peak height of fractional anisotropy (FA) and mean diffusivity (MD) are diffusion tensor imaging (DTI) markers used to quantify white matter microstructure changes. We examine the association of DTI histogram-derived measures in global normal appearing white matter (NAWM) and cognitive decline in patients with normal cognition and cognitive impairment no dementia from a memory clinic in Singapore. Methods: A total of 252 patients (mean age: 71.1 ± 7.6 years, 53.2% women) were included. All patients underwent clinical assessments, a brain MRI scan at baseline, and neuropsychological assessments annually for 2 years. DTI scans were processed to obtain MD and FA histogram-derived measures. The National Institute of Neurological Disorders and Stroke and the Canadian Stroke Network harmonization neuropsychological battery were used to assess cognitive function. Linear regression models with generalised estimating equation (GEE) and logistic regression models were used to examine the association between DTI histogram measures and cognitive decline. Results: When compared to baseline, MD and FA measures at Year 2 were associated with an accelerated worsening in global cognition (all p for interaction <0.001; Year 0 vs 2, MD median: -0.29 (95%CI: -0.49, -0.09) vs -0.45 (95%CI: -0.65,-0.25); MD peak height: 0.22 (95%CI: 0.07, 0.37) vs 0.37 (95%CI: 0.21, 0.53); FA median: 0.11 (95%CI: -0.05, 0.26) vs 0.22 (95%CI: 0.07, 0.37); FA peak height: -0.14 (95%CI: -0.28, 0.00) vs -0.24 (95%CI: -0.38, -0.10);). Similar findings were observed for executive function and visuomotor speed while only MD measures predicted worsening in memory domain. Interpretation: This study shows that DTI histogram measures are associated with accelerated cognitive decline suggesting the utility of DTI as a pre-clinical marker in predicting the worsening of cognition in clinical trials.

Association between nutrition and cognition in a multi-ethnic cohort from Singapore.

BACKGROUND: Nutrition, a modifiable risk factor, presents a low-cost prevention strategy to reduce the burden of cognitive impairment and dementia. However, studies examining the effects of dietary patterns on cognition are lacking in multi-ethnic Asian populations. We investigate the association between diet quality, measured with the Alternative Healthy Eating Index (AHEI)-2010, and cognitive impairment in middle-aged and older adults of different ethnicities (Chinese, Malay, Indian) in Singapore. METHODS: This cross-sectional study (n = 3138; mean age: 50.4 ± 9.8, 58.4% women) was based on data from the Singapore Multi-Ethnic Cohort. Dietary intake collected with a validated semi-quantitative Food Frequency Questionnaire was converted into AHEI-2010 scores. Cognition, assessed with the Mini-Mental State Examination (MMSE), was analysed as a continuous or binary outcome (cognitively impaired or not, using cut-offs of ≥ 24, 26 or 28 for no education, primary school education and secondary school education and above). Multivariable linear and logistic regression models were used to examine associations between AHEI-2010 and cognition, adjusting for covariates. RESULTS: A total of 988 (31.5%) participants had cognitive impairment. Higher AHEI-2010 scores were significantly associated with higher MMSE scores [ß = 0.44; 95% confidence interval (CI) 0.22-0.67 highest vs. lowest quartile; p-trend < 0.001] and lower odds of cognitive impairment [OR 0.69; 95% CI 0.54-0.88; p-trend = 0.01] after adjusting for all the covariates. No significant associations were observed for individual dietary components of the AHEI-2010 with MMSE or cognitive impairment. CONCLUSION: Healthier dietary patterns were associated with better cognitive function in middle-aged and older Singaporeans. These findings could inform better support to promote healthier dietary patterns in Asian populations.

Handgrip Strength and Cognitive Performance in a Multiethnic Cohort in Singapore.

BACKGROUND: Handgrip strength (HGS) is an important marker of frailty but there is limited research on lifestyle and vascular determinants of HGS and its relationship with cognitive impairment. OBJECTIVE: To identify determinants of HGS and the association of HGS with cognitive impairment in a multiethnic cohort from Singapore. METHODS: This study (n = 2,109, median [Q1, Q3] age: 53 [48, 60] years, 59.6% women) was based on cross-sectional data from Singapore Multi-Ethnic Cohort. HGS was collected using hand-held Electronic Dynamometer. The potential determinants of HGS included age, sex, ethnicity, smoking, physical activity, serum cholesterol and history of hypertension, diabetes, and stroke. Cognition, assessed with the Mini-Mental State Examination (MMSE), was analyzed as both continuous and binary outcome (cognitively impaired [scores < 26] and cognitively normal [scores≥26]). RESULTS: In total, 239 (11.3%) participants were cognitively impaired. Older age, female sex, Malay or Indian compared with Chinese ethnicity, and diabetes history were associated with decreased HGS, whereas higher education, higher body mass index, and more physical activity were associated with higher HGS. Higher HGS was associated with higher MMSE scores (ß: 0.34, 95% CI: 0.20, 0.49) and 37% lower odds of cognitive impairment (OR: 0.63, 95% CI: 0.49-0.82). These associations were significantly stronger in participants who were older (50-90 years), female, of Malay and Indian ethnicity (compared with Chinese), and less educated. CONCLUSION: In this multi-ethnic Asian population, demographics, vascular risk factors, and lifestyle behaviors were associated with HGS. Additionally, higher HGS was associated with substantially better cognitive function, which association was modified by age, sex, ethnicity, and education level.