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.

The proportion of dementia attributable to common modifiable lifestyle factors in Barbados / Proporción de casos de demencia atribuible a factores comunes y modificables relacionados con el modo de vida en Barbados / Proporção de demência atribuível a fatores comuns modificáveis do estilo de vida em Barbados

ABSTRACT 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.

RESUMEN Objetivo Establecer el número y la proporción de casos de demencia en Barbados que se pueden atribuir a factores modificables relacionados con el modo de vida y el efecto que podría tener una reducción de estos factores de riesgo en la prevalencia de la demencia en el futuro. Métodos Este fue un estudio de observación en el que se usó la fórmula de riesgo atribuible de Levin, que presupone la independencia de los factores de riesgo, para calcular el riesgo de demencia (por cualquier causa) atribuible a la población (RAP) en Barbados en relación con seis factores de riesgo: obesidad en la edad madura, inactividad física, tabaquismo, nivel de escolaridad bajo, diabetes mellitus e hipertensión en la edad madura. Se utilizó una fórmula modificada de publicación reciente para incluir los factores de riesgo no independientes, sobre la base de datos secundarios para Barbados. Se computaron el número y la proporción de casos de demencia atribuibles a cada factor de riesgo y a todos los factores de riesgo combinados, al igual que el efecto de una reducción de estos factores de riesgo sobre la prevalencia de la demencia. Resultados Teniendo en cuenta el hecho de que los factores de riesgo no operan independientemente, 50,9% de los casos (1 526 casos) se podían atribuir al efecto combinado de los seis factores de riesgo en estudio. Según el análisis, si cada factor de riesgo se redujera de 5% a 20% por decenio, la prevalencia de la demencia podría ser de 3,3% a 31,8% más baja para el 2050. Conclusiones Mediante un modelo mayormente teórico, se estimó que 50,9% de los casos de demencia en Barbados eran atribuibles a seis factores modificables relacionados con el modo de vida. Como los factores de riesgo tienen mucho en común, cualquier intervención dirigida específicamente a uno de ellos podría reducir considerablemente la prevalencia de la demencia en el futuro.

RESUMO Objetivo Conhecer o número e a proporção de casos de demência em Barbados que são atribuíveis a fatores modificáveis do estilo de vida e examinar o efeito que teria uma redução desses fatores de risco na prevalência futura de demência. Métodos Estudo observacional realizado com o uso da fórmula do risco atribuível de Levin (pressuposto de independência dos fatores de risco) para calcular o risco atribuível populacional (RAP) da demência (todas as causas) em Barbados para seis fatores de risco: obesidade na meia idade, inatividade física, tabagismo, baixo grau de instrução, diabetes mellitus e hipertensão na meia idade. Uma versão modificada da fórmula recentemente publicada foi usada para representar a não independência dos fatores de risco usando dados secundários do país. O número e a proporção de casos de demência atribuíveis a cada fator de risco e a todos os fatores de risco combinados foram computados, assim como o efeito de uma redução desses fatores de risco na prevalência futura de demência. Resultados Considerando que os fatores do risco não atuam de modo independente, 50,9% (1.526 casos) foram atribuíveis ao efeito combinado dos seis fatores de risco estudados. De acordo com a análise, se cada fator de risco tivesse uma redução de 5%-20% por década, a prevalência da demência poderia cair de 3,3% a 31,8% até 2050. Conclusões De acordo com um modelo eminentemente teórico, estimou-se que os seis fatores modificáveis do estilo de vida eram atribuíveis a 50,9% dos casos de demência em Barbados. Visto que os fatores de risco têm muito em comum, qualquer intervenção que vise um dos fatores poderia reduzir consideravelmente a prevalência futura da demência.

Proportion of dementia in Australia explained by common modifiable risk factors.

BACKGROUND: At present, dementia has no known cure. Interventions to delay onset and reduce prevalence of the disease are therefore focused on risk factor reduction. Previous population attributable risk estimates for western countries may have been underestimated as a result of the relatively low rates of midlife obesity and the lower weighting given to that variable in statistical models. METHODS: Levin's Attributable Risk which assumes independence of risk factors was used to calculate the proportion of dementia attributable to seven modifiable risk factors (midlife obesity, physical inactivity, smoking, low educational attainment, diabetes mellitus, midlife hypertension and depression) in Australia. Using a recently published modified formula and survey data from the Australia Diabetes, Obesity and Lifestyle Study, a more realistic population attributable risk estimate which accounts for non-independence of risk factors was calculated. Finally, the effect of a 5-20% reduction in each risk factor per decade on future dementia prevalence was computed. RESULTS: Taking into consideration that risk factors do not operate independently, a more conservative estimate of 48.4% of dementia cases (117,294 of 242,500 cases) was found to be attributable to the seven modifiable lifestyle factors under study. We calculated that if each risk factor was to be reduced by 5%, 10%, 15% and 20% per decade, dementia prevalence would be reduced by between 1.6 and 7.2% in 2020, 3.3-14.9% in 2030, 4.9-22.8% in 2040 and 6.6-30.7% in 2050. CONCLUSION: Our largely theory-based findings suggest a strong case for greater investment in risk factor reduction programmes that target modifiable lifestyle factors, particularly increased engagement in physical activity. However, further data on risk factor treatment and dementia risk reduction from population-based studies are needed to investigate whether our estimates of potential dementia prevention are indeed realistic.

Relating education, brain structure, and cognition: the role of cardiovascular disease risk factors.

The protective effect of education on cognitive and brain health is well established. While the direct effects of individual cardiovascular disease (CVD) risk factors (i.e., hypertension, smoking, diabetes, and obesity) on cerebral structure have been investigated, little is understood about the possible interaction between the protective effect of education and the deleterious effects of CVD risk factors in predicting brain ageing and cognition. Using data from the PATH Through Life study (N = 266), we investigated the protective effect of education on cerebral structure and function and tested a possible mediating role of CVD risk factors. Higher education was associated with larger regional grey/white matter volumes in the prefrontal cortex in men only. The association between education and cognition was mediated by brain volumes but only for grey matter and only in relation to information processing speed. CVD risk factors did not mediate the association between regional volumes and cognition. This study provides additional evidence in support for a protective effect of education on cerebral structures and cognition. However, it does not provide support for a mediating role of CVD risk factors in these associations.

Alcohol and smoking consumption behaviours in older Australian adults: prevalence, period and socio-demographic differentials in the DYNOPTA sample.

PURPOSE: Alcohol consumption and tobacco use are key risk factors for chronic disease and health burden across the adult lifespan. We estimate the prevalence of alcohol consumption and smoking by age and time period in adults from mid to old age. METHODS: Participants (n = 50,652) were drawn from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project and were compared with Australian National Health Survey data. Alcohol and smoking consumption DYNOPTA data were weighted to the estimated resident population of the sampling frame for each contributing study according to age and sex distributions within major statistical regions. RESULTS: Comparisons in the rates of smoking and alcohol consumption between DYNOPTA and other national surveys were comparable. Males were more likely to be (RRR = 2.12) or have been smokers (RRR = 2.97), whilst females were more likely to be non-drinkers (RRR = 2.52). Period effects were also identified; higher prevalence rates in consumption of alcohol (RRR = 3.21) and smoking (RRR = 1.67) for those contributing studies from the early 1990's, in comparison with those studies from the latter half of the decade, were reported. CONCLUSIONS: Over a decade, prevalence rates for high-risk consumption of alcohol and current smoking behaviour declined and suggest the possible impact of government health policy, with targeted-health policies, that included bans on public smoking, and a toughening of legislation against alcohol-related crime.

Alcohol use and depression from middle age to the oldest old: gender is more important than age.

BACKGROUND: Alcohol use disorders are associated with other mental health disorders in young adults, but there are few data on alcohol use and mental health outcomes in older adults, particularly the oldest old. This study examines the relationship between alcohol consumption and depressive symptoms. METHODS: Data were collected from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project, which has pooled nine Australian longitudinal studies. Alcohol consumption was classified using standard drinks (10 g alcohol)/day as: abstinent, low risk (<0-≤ 2 standard drinks), long-term risk (>2-≤ 4) and short-term risk (>4). Probable depression was classified from harmonized scores on various standard instruments (e.g. Centre for Epidemiological Studies Depression scale). RESULTS: Overall, 39,104 (86%) participants contributed data. Alcohol classification at baseline showed 7,526 abstinent, 28,112 low risk, 2,271 long-term risk, and 1,195 short-term risk participants. Age ranged from 45 to 103 year (median 60). Using generalized estimating equations (GEE), there were significant gender by alcohol and gender by age interactions, so the analysis was split by gender. Among males, the abstinent and short-term risk groups had increased likelihood of depression: in females the abstinent, long- and short-term risk groups had increased odds of depression. Increased odds of depression was also associated with former and current smoking, younger age-group, not being partnered, leaving school before age 15 and increasing levels of health-impaired walking, dressing, or bathing. CONCLUSION: The impact of alcohol use differs by gender, nevertheless those using higher levels of alcohol or who smoke should be screened for depression and may benefit from interventions.

Deriving prevalence estimates of depressive symptoms throughout middle and old age in those living in the community.

BACKGROUND: There is considerable debate about the prevalence of depression in old age. Epidemiological surveys and clinical studies indicate mixed evidence for the association between depression and increasing age. We examined the prevalence of probable depression in the middle aged to the oldest old in a project designed specifically to investigate the aging process. METHODS: Community-living participants were drawn from several Australian longitudinal studies of aging that contributed to the Dynamic Analyses to Optimise Ageing (DYNOPTA) project. Different depression scales from the contributing studies were harmonized to create a binary variable that reflected "probable depression" based on existing cut-points for each harmonized scale. Weighted prevalence was benchmarked to the Australian population which could be compared with findings from the 1997 and 2007 National Surveys of Mental Health and Well-Being (NSMHWB). RESULTS: In the DYNOPTA project, females were more likely to report probable depression. This was consistent across age levels. Both NSMHWB surveys and DYNOPTA did not report a decline in the likelihood of reporting probable depression for the oldest old in comparison with mid-life. CONCLUSIONS: Inconsistency in the reports of late-life depression prevalence in previous epidemiological studies may be explained by either the exclusion and/or limited sampling of the oldest old. DYNOPTA addresses these limitations and the results indicated no change in the likelihood of reporting depression with increasing age. Further research should extend these findings to examine within-person change in a longitudinal context and control for health covariates.

The Lung Image Database Consortium (LIDC) and Image Database Resource Initiative (IDRI): a completed reference database of lung nodules on CT scans.

PURPOSE: The development of computer-aided diagnostic (CAD) methods for lung nodule detection, classification, and quantitative assessment can be facilitated through a well-characterized repository of computed tomography (CT) scans. The Lung Image Database Consortium (LIDC) and Image Database Resource Initiative (IDRI) completed such a database, establishing a publicly available reference for the medical imaging research community. Initiated by the National Cancer Institute (NCI), further advanced by the Foundation for the National Institutes of Health (FNIH), and accompanied by the Food and Drug Administration (FDA) through active participation, this public-private partnership demonstrates the success of a consortium founded on a consensus-based process. METHODS: Seven academic centers and eight medical imaging companies collaborated to identify, address, and resolve challenging organizational, technical, and clinical issues to provide a solid foundation for a robust database. The LIDC/IDRI Database contains 1018 cases, each of which includes images from a clinical thoracic CT scan and an associated XML file that records the results of a two-phase image annotation process performed by four experienced thoracic radiologists. In the initial blinded-read phase, each radiologist independently reviewed each CT scan and marked lesions belonging to one of three categories ("nodule > or =3 mm," "nodule <3 mm," and "non-nodule > or =3 mm"). In the subsequent unblinded-read phase, each radiologist independently reviewed their own marks along with the anonymized marks of the three other radiologists to render a final opinion. The goal of this process was to identify as completely as possible all lung nodules in each CT scan without requiring forced consensus. RESULTS: The Database contains 7371 lesions marked "nodule" by at least one radiologist. 2669 of these lesions were marked "nodule > or =3 mm" by at least one radiologist, of which 928 (34.7%) received such marks from all four radiologists. These 2669 lesions include nodule outlines and subjective nodule characteristic ratings. CONCLUSIONS: The LIDC/IDRI Database is expected to provide an essential medical imaging research resource to spur CAD development, validation, and dissemination in clinical practice.

Cardiovascular risk factors and life events as antecedents of depressive symptoms in middle and early-old age: PATH Through Life Study.

OBJECTIVE: To evaluate cardiovascular risk factors (CVRF) and life events (LE) as predictors of depressive symptoms in a mid-life and an early late-life cohort to determine whether they had independent or interacting effects, and whether there were age differences in the effects. METHODS: Cohorts aged 40 to 44 years (n = 2530) and 60 to 64 years (n = 2551) at baseline (Wave 1) were followed up after 4 years (Wave 2) as part of the PATH Through Life Study based in Canberra and Queanbeyan, Australia. Cross-sectional analyses evaluated rates of CVRF and LE in depressed compared with nondepressed participants. Hierarchical generalized linear models were used to evaluate demographic variables, CVRF (diabetes, smoking, alcohol, body mass index, cholesterol medication, hypertension), LE, and Wave 1 depressive symptoms as predictors of depressive symptoms at Wave 2. RESULTS: At baseline, those with high levels of depressive symptoms were more likely to report smoking, using cholesterol-lowering medications, hypertension, diabetes, past stroke, and higher body mass index. Predictors of depressive symptoms at Wave 2 in the cohort of 40- to 44-year-old persons included Wave 1 depressive symptoms, diabetes, and LE at Wave 2. In the cohort of 60- to 64-year-old individuals, Wave 1 depression, stroke, smoking, low education, and Wave 2 LE predicted depressive symptoms. There was no evidence of interactions between CVRF and LE. CONCLUSIONS: LE and CVRF are independent sets of risk factors for depressive symptoms with different effects in the 40- to 44-year-old and 60- to 64-year-old cohorts. These findings have implications for preventative strategies for depression.

The treatment of obesity.

Obesity is a chronic problem requiring lifelong treatment. Obesity assessment involves measurement of the body mass index, waist circumference, and the identification of other risk factors. Management should include diet and exercise. Selected patients can be offered pharmacotherapy, of which only sibutramine and orlistat are FDA-approved for long-term use. Bariatric surgery is the only option that provides sustained and significant weight loss and should be offered to the severely obese patients.