Determinants of cognitive performance and decline in 20 diverse ethno-regional groups: A COSMIC collaboration cohort study

Background: With no effective treatments for cognitive decline or dementia, improving the evidence base for modifiable risk factors is a research priority. This study investigated associations between risk factors and late-life cognitive decline on a global scale, including comparisons between ethno-regional groups. Methods and findings: We harmonized longitudinal data from 20 population-based cohorts from 15 countries over 5 continents, including 48,522 individuals (58.4% women) aged 54–105 (mean = 72.7) years and without dementia at baseline. Studies had 2–15 years of follow-up. The risk factors investigated were age, sex, education, alcohol consumption, anxiety, apolipoprotein E ε4 allele (APOE*4) status, atrial fibrillation, blood pressure and pulse pressure, body mass index, cardiovascular disease, depression, diabetes, self-rated health, high cholesterol, hypertension, peripheral vascular disease, physical activity, smoking, and history of stroke. Associations with risk factors were determined for a global cognitive composite outcome (memory, language, processing speed, and executive functioning tests) and Mini-Mental State Examination score. Individual participant data meta-analyses of multivariable linear mixed model results pooled across cohorts revealed that for at least 1 cognitive outcome, age (B = −0.1, SE = 0.01), APOE*4 carriage (B = −0.31, SE = 0.11), depression (B = −0.11, SE = 0.06), diabetes (B = −0.23, SE = 0.10), current smoking (B = −0.20, SE = 0.08), and history of stroke (B = −0.22, SE = 0.09) were independently associated with poorer cognitive performance (p < 0.05 for all), and higher levels of education (B = 0.12, SE = 0.02) and vigorous physical activity (B = 0.17, SE = 0.06) were associated with better performance (p < 0.01 for both). Age (B = −0.07, SE = 0.01), APOE*4 carriage (B = −0.41, SE = 0.18), and diabetes (B = −0.18, SE = 0.10) were independently associated with faster cognitive decline (p < 0.05 for all). Different effects between Asian people and white people included stronger associations for Asian people between ever smoking and poorer cognition (group by risk factor interaction: B = −0.24, SE = 0.12), and between diabetes and cognitive decline (B = −0.66, SE = 0.27; p < 0.05 for both). Limitations of our study include a loss or distortion of risk factor data with harmonization, and not investigating factors at midlife. Conclusions: These results suggest that education, smoking, physical activity, diabetes, and stroke are all modifiable factors associated with cognitive decline. If these factors are determined to be causal, controlling them could minimize worldwide levels of cognitive decline. However, any global prevention strategy may need to consider ethno-regional differences

New insights into the genetic etiology of Alzheimer's disease and related dementias.

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3�6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55 of the global rise in mean BMI from 1985 to 2017�and more than 80 in some low- and middle-income regions�was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing�and in some countries reversal�of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories. © 2019, The Author(s)

Social life characteristics in relation to adherence to the Mediterranean diet in older adults: Findings from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD) study

Objective: The present study aimed to explore the associations between social life and adherence to a healthy dietary pattern, the Mediterranean diet (MD), in a population-representative cohort of older people.Design: Cross-sectional study. Adherence to the MD was evaluated by an a priori score; tertiles of the score, indicating low, medium and high adherence, were used in the analyses. Social life was assessed by a questionnaire evaluating participation in leisure-time activities and the number of social contacts; primary occupation was also recorded and job characteristics were further explored.Setting: Community-dwelling older adults.Participants: Adults from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD) study (n 1933; age range 65-99 years).Results: Each unit increase in the number of social contacts/month and in the frequency score of intellectual, social and physical activities was associated with a 1·6, 6·8, 4·8 and 13·7 % increase in the likelihood of a participant being in the high MD adherence group, respectively. The analysis by age group revealed that younger elderly participants had a 1·4, 8·4 and 11·3 % higher likelihood to be in the high adherence group for each unit increase in the number of social contacts/month and in the frequency score of engagement in intellectual and physical activities, respectively. Similar associations were found for older elderly participants with high compared with low MD adherence, except for the intellectual activities.Conclusions: The present results suggest that high MD adherence is associated with good social life, suggesting a clustering of health-promoting lifestyle factors in older adults. © 2019 The Authors

Social life characteristics in relation to adherence to the Mediterranean diet in older adults: Findings from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD) study

Objective: The present study aimed to explore the associations between social life and adherence to a healthy dietary pattern, the Mediterranean diet (MD), in a population-representative cohort of older people.Design: Cross-sectional study. Adherence to the MD was evaluated by an a priori score; tertiles of the score, indicating low, medium and high adherence, were used in the analyses. Social life was assessed by a questionnaire evaluating participation in leisure-time activities and the number of social contacts; primary occupation was also recorded and job characteristics were further explored.Setting: Community-dwelling older adults.Participants: Adults from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD) study (n 1933; age range 65-99 years).Results: Each unit increase in the number of social contacts/month and in the frequency score of intellectual, social and physical activities was associated with a 1·6, 6·8, 4·8 and 13·7 % increase in the likelihood of a participant being in the high MD adherence group, respectively. The analysis by age group revealed that younger elderly participants had a 1·4, 8·4 and 11·3 % higher likelihood to be in the high adherence group for each unit increase in the number of social contacts/month and in the frequency score of engagement in intellectual and physical activities, respectively. Similar associations were found for older elderly participants with high compared with low MD adherence, except for the intellectual activities.Conclusions: The present results suggest that high MD adherence is associated with good social life, suggesting a clustering of health-promoting lifestyle factors in older adults. © 2019 The Authors

Adherence to Mediterranean Diet and Frailty

Objective: Το investigate associations between adherence to the Mediterranean diet and frailty in a Greek population of older adults. Design: Cross-sectional study. Setting: Data were drawn from the Hellenic longitudinal Investigation of Aging and Diet (HELIAD), a population-based, multidisciplinary study designed to estimate the prevalence and incidence of dementia in the Greek population. Participants: Data from 1740 participants aged ≥65 years were included in the present analysis. Participants were selected through random sampling from the records of 2 Greek municipalities. Measurements: Adherence to Mediterranean diet was evaluated through the MedDietScore, calculated from the information participants provided to a validated food frequency questionnaire. Frailty was assessed using 3 different definitions (the phenotypic approach proposed by Fried et al, the Frailty Index, and the Tilburg Frailty Indicator). Unadjusted and adjusted logistic and linear regression models were performed. Results: Of our participants, 70 (4%), 325 (18.7%), and 442 (25.4%) were identified as frail according to the Fried et al definition, the Frailty Index, and the Tilburg Frailty Indicator, respectively. Adjusting for confounding factors, each additional unit in the MedDietScore was associated with a 5% (P =.09), 4% (P =.005), and 7% (P &lt;.001) decrease in the odds for frailty according to the Fried definition, the Frailty Index, and the Tilburg Frailty Indicator, respectively. Conclusions: According to study results, a higher adherence to the Mediterranean diet was associated with lower odds of frailty, irrespective of the definition used. This finding may be of relevance in the setting of population-based prevention efforts as well as in clinical practice. © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicin

Adherence to Mediterranean Diet and Frailty

Objective: Το investigate associations between adherence to the Mediterranean diet and frailty in a Greek population of older adults. Design: Cross-sectional study. Setting: Data were drawn from the Hellenic longitudinal Investigation of Aging and Diet (HELIAD), a population-based, multidisciplinary study designed to estimate the prevalence and incidence of dementia in the Greek population. Participants: Data from 1740 participants aged ≥65 years were included in the present analysis. Participants were selected through random sampling from the records of 2 Greek municipalities. Measurements: Adherence to Mediterranean diet was evaluated through the MedDietScore, calculated from the information participants provided to a validated food frequency questionnaire. Frailty was assessed using 3 different definitions (the phenotypic approach proposed by Fried et al, the Frailty Index, and the Tilburg Frailty Indicator). Unadjusted and adjusted logistic and linear regression models were performed. Results: Of our participants, 70 (4%), 325 (18.7%), and 442 (25.4%) were identified as frail according to the Fried et al definition, the Frailty Index, and the Tilburg Frailty Indicator, respectively. Adjusting for confounding factors, each additional unit in the MedDietScore was associated with a 5% (P =.09), 4% (P =.005), and 7% (P <.001) decrease in the odds for frailty according to the Fried definition, the Frailty Index, and the Tilburg Frailty Indicator, respectively. Conclusions: According to study results, a higher adherence to the Mediterranean diet was associated with lower odds of frailty, irrespective of the definition used. This finding may be of relevance in the setting of population-based prevention efforts as well as in clinical practice. © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicin

Associations between sleep and obesity indices in older adults: results from the HELIAD study

Background: Short sleep duration and low sleep quality are negatively associated with obesity in young adults, but in older people the results are inconsistent. Aims: The aim of the present study was to examine the associations between sleep duration and quality with both body mass index (BMI) and waist circumference (WC) and to investigate sex- and age-specific associations in a population-representative cohort of older adults. Methods: 1781 participants ≥ 65 years old from the HELIAD study were included. Sleep duration and quality were based on self-report, whereas BMΙ and WC were evaluated clinically. Results: Sleep duration was inversely related to WC, only in women, even after adjustment for age, sex, years of education, total energy intake and level of physical activity. Furthermore, sleep quality was negatively related to both BMI and WC in women. In men, however, no significant relationships were observed between these variables. Associations between sleep and weight did not differ between those aged &lt; 73 and ≥ 73 years old. Discussion: To the best of our knowledge, this is the first study examining both sleep duration and quality with BMI and WC in older adults, performing by-sex analysis. Although additional studies are needed, improvements in sleep habits should be considered in weight management of older individuals. Conclusions: Our results suggest that poor sleep is associated to adverse weight effects in older women, but not men. © 2019, Springer Nature Switzerland AG

Associations between sleep and obesity indices in older adults: results from the HELIAD study

Background: Short sleep duration and low sleep quality are negatively associated with obesity in young adults, but in older people the results are inconsistent. Aims: The aim of the present study was to examine the associations between sleep duration and quality with both body mass index (BMI) and waist circumference (WC) and to investigate sex- and age-specific associations in a population-representative cohort of older adults. Methods: 1781 participants ≥ 65 years old from the HELIAD study were included. Sleep duration and quality were based on self-report, whereas BMΙ and WC were evaluated clinically. Results: Sleep duration was inversely related to WC, only in women, even after adjustment for age, sex, years of education, total energy intake and level of physical activity. Furthermore, sleep quality was negatively related to both BMI and WC in women. In men, however, no significant relationships were observed between these variables. Associations between sleep and weight did not differ between those aged < 73 and ≥ 73 years old. Discussion: To the best of our knowledge, this is the first study examining both sleep duration and quality with BMI and WC in older adults, performing by-sex analysis. Although additional studies are needed, improvements in sleep habits should be considered in weight management of older individuals. Conclusions: Our results suggest that poor sleep is associated to adverse weight effects in older women, but not men. © 2019, Springer Nature Switzerland AG