The proportion of dementia attributable to common modifiable lifestyle factors in Barbados

Objective. To understand what number and proportion of dementia cases in Barbados are attributable to modifiable lifestyle factors and what effect a reduction in these risk factors would have on future dementia prevalence. Methods. This was an observational study using Levin’s Attributable Risk formula, which assumes independence of risk factors, to calculate the population attributable risk (PAR) of dementia (all-cause) for six risk factors: midlife obesity, physical inactivity, smoking, low educational attainment, diabetes mellitus, and midlife hypertension in Barbados. A recently-published, modified formula was utilized to account for non- independence of risk factors using secondary data for Barbados. The number and proportion of dementia cases attributable to each risk factor and to all risk factors combined were computed, as was the effect that any reduction in these risk factors might have on future dementia prevalence. Results. Accounting for the fact that risk factors do not operate independently, 50.9% (1 526 cases) were attributable to the combined effect of the six risk factors under study. According to the analysis, if each risk factor were reduced by 5% – 20% per decade, dementia prevalence could be 3.3% – 31.8% lower by 2050. Conclusion. Using a largely theoretical model, the six modifiable lifestyle factors were estimated to be attributable to 50.9% of dementia cases in Barbados. Since the risk factors have much in common, any intervention that targets one of them could significantly reduce future dementia prevalence.This work was supported by the Australian Research Council Centre of Excellence in Population Ageing Research (Canberra, Australian Capital Territory; CE110001029), Australian Research Council (Canberra, Australian Capital Territory; Fellowship #120100227) and by the National Health and Medical Research Council (NHMRC; Canberra, Australian Capital Territory; Fellowship #1002560 and APP1079438). We also acknowledge support from the NHMRC Dementia Collaborative Research Centres (Canberra, Australian Capital Territory)

Cognitive Impairment in Australia and Latin American and Caribbean Countries: Life Expectancy, Diet and Physical Activity, and the Potential for Prevention

The prevalence of moderate or severe cognitive impairment (CIm) rises steeply with age. It is well documented that our populations (both in developed and low- and middle-income countries) are ageing and that lifestyle factors may hold the key to preserving mental and functional status. This thesis adopts a cross-national approach between Australia and seven Latin American and Caribbean (LAC) countries and focuses on two modifiable lifestyle factors – diet and physical activity. Two data sets are utilised in this thesis – the Australia Diabetes, Obesity and Lifestyle Study (AusDiab)and the Survey on Health, Well-Being, and Ageing in LAC (SABE). AusDiab represents the largest Australian longitudinal population-based study examining the natural history of diabetes, pre-diabetes, heart disease and kidney disease. Three Waves of data have been collected thus far with cognitive function examined at the most recent Wave only. The SABE is a 7-country survey conducted in LAC in 2000. The SABE represents the only comprehensive health-related data set for persons over the age of 60 in the region that takes into account cognitive status. Using the Sullivan Method for calculating health expectancies, it was found that in Australia females live longer than males and males spend more time with CIm. In LAC, substantial differences in the absolute years lived and the proportion of remaining life spent free of CIm were observed. Total life expectancy (TLE) and cognitive impairment-free life expectancy (CIFLE) at age 60 years were highest in Brazil and Mexico and lowest in Uruguay and Cuba. Both a priori and a posteriori methods were used to examine the relationship between diet, physical activity and cognition. In the first instance, greater adherence to the Mediterranean Diet (MeDi), engagement in physical activity, and television viewing time were not predictive of CIm among older adults in the Australian sample. In the second instance using principal component analysis (PCA), complex patterns of associations between dietary factors and cognition were evident in the Australian sample. The most consistent finding was the protective effects of high vegetable and plant-based food item consumption and negative effects of ‘Western’ patterns on cognition. Among LAC countries, weekly consumption of milk and cheese, eggs, peas and beans, meat, fish or poultry, and fruits or vegetables were significantly associated with CIm. Regular exercise or participation in vigorous physical activity such as playing a sport, dancing or heavy housework three or more times a week was significantly associated with CIm in Chile, Mexico and Uruguay. Using a modified population attributable risk formula which accounts for non-independence of risk factors, an estimated 39.0% of dementia cases in Australia may be attributable to five modifiable risk factor (excess alcohol consumption, midlife obesity, physical inactivity, smoking and low educational attainment). In the LAC region, diabetes mellitus, physical inactivity and smoking were estimated to be attributable to 21.9% of cases in Barbados, 14.7% in Mexico, and 26.2% in Cuba. If each risk factor were to be reduced by 10% and 20% every 10 years to 2050, dementia prevalence could be reduced by up to 24.7% in Australia and up to 16.3% in LAC countries. This thesis highlights the need for greater investment in research, interventions and policies targeting modifiable lifestyle factors to reduce CIm risk factor prevalence at the population level. In addition, the need for more research in the LAC region (particularly longitudinal studies) is highlighted. Overall, the findings suggest that there is a need for further studies to better understand more nuanced topics, such as the effect of composite dietary patterns on cognitive decline and the nutrition-cognition link in different populations, as there is a general paucity of data sources designed to address these issues

Role of dietary pattern analysis in determining cognitive status in elderly Australian adults

Principal Component Analysis (PCA) was used to determine the association between dietary patterns and cognitive function and to examine how classification systems based on food groups and food items affect levels of association between diet and cognitive function. The present study focuses on the older segment of the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) sample (age 60+) that completed the food frequency questionnaire at Wave 1 (1999/2000) and the mini-mental state examination and tests of memory, verbal ability and processing speed at Wave 3 (2012). Three methods were used in order to classify these foods before applying PCA. In the first instance, the 101 individual food items asked about in the questionnaire were used (no categorisation). In the second and third instances, foods were combined and reduced to 32 and 20 food groups, respectively, based on nutrient content and culinary usage—a method employed in several other published studies for PCA. Logistic regression analysis and generalized linear modelling was used to analyse the relationship between PCA-derived dietary patterns and cognitive outcome. Broader food group classifications resulted in a greater proportion of food use variance in the sample being explained (use of 101 individual foods explained 23.22% of total food use, while use of 32 and 20 food groups explained 29.74% and 30.74% of total variance in food use in the sample, respectively). Three dietary patterns were found to be associated with decreased odds of cognitive impairment (CI). Dietary patterns derived from 101 individual food items showed that for every one unit increase in ((Fruit and Vegetable Pattern: p = 0.030, OR 1.061, confidence interval: 1.006–1.118); (Fish, Legumes and Vegetable Pattern: p = 0.040, OR 1.032, confidence interval: 1.001–1.064); (Dairy, Cereal and Eggs Pattern: p = 0.003, OR 1.020, confidence interval: 1.007–1.033)), the odds of cognitive impairment decreased. Different results were observed when the effect of dietary patterns on memory, processing speed and vocabulary were examined. Complex patterns of associations between dietary factors and cognition were evident, with the most consistent finding being the protective effects of high vegetable and plant-based food item consumption and negative effects of ‘Western’ patterns on cognition. Further long-term studies and investigation of the best methods for dietary measurement are needed to better understand diet-disease relationships in this age group

Life expectancy in Australian senior with or without cognitive impairment: the Australia Diabetes, Obesity and Lifestyle Study Wave 3

Objective: To determine prevalence of cognitive impairment (CI) and to estimate life expectancy with and without cognitive impairment in the Australian population over age 60. Method: Adults aged 60 and older participating in the 12 year follow-up of the Australia Diabetes Obesity and Lifestyle Study (AusDiab) were included in the sample (n=1666). The mean age was 69.5 years, and 46.3% of the sample was male. The Mini-Mental State Examination was used to assess cognitive impairment. Logistic regression analysis was used to determine the effect of predictor variables (age, gender, education), measured at baseline, on cognitive impairment status. The Sullivan Method was used to estimate Total Life Expectancy (TLE), Cognitively Impaired (CILE) and Cognitive Impairment-free life expectancies (CIFLE). Results: Odds of CI were greater for males than females (OR 2.1, 95% confidence interval: 1.2-3.7) and among Australians with low education levels compared with Australians with high education levels (OR 2.1, 95% confidence interval: 1.2-3.7). The odds of CI also increased each year with age (OR 1.1, (95% confidence interval: 1.0-1.1). It was found that in all age groups females have greater TLE and CIFLE when compared to their male counterparts.This research was supported by the Australian Research Council Centre of Excellence in Population Aging Research (project number CE110001029). KJA is funded by NHMRC Fellowship #1002560. We acknowledge support from the NHMRC Dementia Collaborative Research Centres. The AusDiab study co-coordinated by the Baker IDI Heart and Diabetes Institute, gratefully acknowledges the support and assistance given by: K Anstey, B Atkins, B Balkau, E Barr, A Cameron, S Chadban, M de Courten, D Dunstan, A Kavanagh, D Magliano, S Murray, N Owen, K Polkinghorne, J Shaw, T Welborn, P Zimmet and all the study participants. Also, for funding or logistical support, we are grateful to: National Health and Medical Research Council (NHMRC grants 233200 and 1007544), Australian Government Department of Health and Aging, Abbott Australasia Pty Ltd, Alphapharm Pty Ltd, Amgen Australia, AstraZeneca, Bristol-Myers Squibb, City Health Centre-Diabetes Service-Canberra, Department of Health and Community Services- Northern Territory, Department of Health and Human Services– Tasmania, Department of Health–New South Wales, Department of Health–Western Australia, Department of Health–South Australia, Department of Human Services–Victoria, Diabetes Australia, Diabetes Australia Northern Territory, Eli Lilly Australia, Estate of the Late Edward Wilson, GlaxoSmithKline, Jack Brockhoff Foundation, Janssen-Cilag, Kidney Health Australia, Marian & FH Flack Trust, Menzies Research Institute, Merck Sharp & Dohme, Novartis Pharmaceuticals, Novo Nordisk Pharmaceuticals, Pfizer Pty Ltd, Pratt Foundation, Queensland Health, Roche Diagnostics Australia, Royal Prince Alfred Hospital, Sydney, Sanofi Aventis, sanofi-synthelabo, and the Victorian Government’s OIS Program

Updating the evidence on the association between serum cholesterol and risk of late-life dementia

Background: Cohort studies have reported that midlife high total serum cholesterol (TC) is associated with increased risk of Alzheimer’s disease (AD) in late-life but findings have been based on few studies and previous reviews have been limited by a lack of compatible data. Objective: We synthesized all high quality data from cohort studies reporting on the association between total serum cholesterol measured and late-life cognitive outcomes including Alzheimer’s disease (AD), vascular dementia (VaD), any dementia, mild cognitive impairment (MCI), and cognitive decline. Methods: The literature was searched up to October 2016 using a registered protocol. Thirty-four articles meeting study criteria were identified. Seventeen studies published from 1996 to 2014, including 23,338 participants were included in meta-analyses. Results: Relative risk of developing AD for adults with high TC in midlife was 2.14 (95% CI 1.33–3.44) compared with normal cholesterol. Individual studies that could not be pooled also reported high TC in midlife increased the risk of MCI and cognitive decline in late-life. High TC in late-life was not associated with MCI, AD, VaD, any dementia, or cognitive decline. Late-life measured HDL cholesterol and triglycerides were not associated with increased risk of VaD, and HDL was not associated with risk of MCI, AD, or any dementia. There were insufficient data to examine other cholesterol sub-fractions, sex differences, or APOE interactions. Conclusions: Significant gaps in the literature regarding TC and late-life dementia remain. Evidence suggests that high midlife TC increases risk of late-life AD, and may correlate with the onset of AD pathology.This work was supported by NHMRC Research Fellowship #1002560 for KJA, and NIHR fellowship PDF-2012-05-197 for RP

Reducing the risk of cognitive decline and dementia: WHO recommendations

With population ageing worldwide, dementia poses one of the greatest global challenges for health and social care in the 21st century. In 2019, around 55 million people were affected by dementia, with the majority living in low- and middle-income countries. Dementia leads to increased costs for governments, communities, families and individuals. Dementia is overwhelming for the family and caregivers of the person with dementia, who are the cornerstone of care and support systems throughout the world. To assist countries in addressing the global burden of dementia, the World Health Organisation (WHO) developed the Global Action Plan on the Public Health Response to Dementia 2017–2025. It proposes actions to be taken by governments, civil society, and other global and regional partners across seven action areas, one of which is dementia risk reduction. This paper is based on WHO Guidelines on risk reduction of cognitive decline and dementia and presents recommendations on evidence-based, multisectoral interventions for reducing dementia risks, considerations for their implementation and policy actions. These global evidence-informed recommendations were developed by WHO, following a rigorous guideline development methodology and involved a panel of academicians and clinicians with multidisciplinary expertise and representing geographical diversity. The recommendations are considered under three broad headings: lifestyle and behaviour interventions, interventions for physical health conditions and specific interventions. By supporting health and social care professionals, particularly by improving their capacity to provide gender and culturally appropriate interventions to the general population, the risk of developing dementia can be potentially reduced, or its progression delayed

Life Expectancy with and without Cognitive Impairment in Seven Latin American and Caribbean Countries

<div><p>Background</p><p>The rising prevalence of cognitive impairment is an increasing challenge with the ageing of our populations but little is known about the burden in low- and middle- income Latin American and Caribbean countries (LAC) that are aging more rapidly than their developed counterparts. We examined life expectancies with cognitive impairment (CILE) and free of cognitive impairment (CIFLE) in seven developing LAC countries.</p><p>Methods</p><p>Data from The Survey on Health, Well-being and Ageing in LAC (N = 10,597) was utilised and cognitive status was assessed by the Mini-Mental State Examination (MMSE). The Sullivan Method was applied to estimate CILE and CIFLE. Logistic regression was used to determine the effect of age, gender and education on cognitive outcome. Meta-regression models were fitted for all 7 countries together to investigate the relationship between CIFLE and education in men and women at age 60.</p><p>Results</p><p>The prevalence of CI increased with age in all countries except Uruguay and with a significant gender effect observed only in Mexico where men had lower odds of CI compared to women [OR = 0.464 95% CInt (0.268 – 0.806)]. Low education was associated with increased prevalence of CI in Brazil [OR = 4.848 (1.173–20.044)], Chile [OR = 3.107 (1.098–8.793), Cuba [OR = 2.295 (1.247–4.225)] and Mexico [OR = 3.838 (1.368–10.765). For males, total life expectancy (TLE) at age 60 was highest in Cuba (19.7 years) and lowest in Brazil and Uruguay (17.6 years). TLE for females at age 60 was highest for Chileans (22.8 years) and lowest for Brazilians (20.2 years). CIFLE for men was greatest in Cuba (19.0 years) and least in Brazil (16.7 years). These differences did not appear to be explained by educational level (Men: p = 0.408, women: p = 0.695).</p><p>Conclusion</p><p>Increasing age, female sex and low education were associated with higher CI in LAC reflecting patterns found in other countries.</p></div

Additional file 1: of Proportion of dementia in Australia explained by common modifiable risk factors

Results of Sensitivity Analysis – PAR of dementia for each risk factor and number of cases attributable in 2010. Table showing the PAR estimates obtained for Australia if the relative risks used in the Norton et.al. 2014 paper had been utilised in the present study. (DOCX 14 kb

TLE and CIFLE at age 60 by Country and Gender.

<p>Total Life Expectancy (TLE) and Cognitive Impairment-Free Life Expectancy (CIFLE) comparisons can be made among each of the seven countries included in the study.</p