Association of psychological distress late in life and dementia-related mortality.

OBJECTIVE: It is not fully understood how subjective feelings of psychological distress prognosticate dementia. Our aim was to investigate the association between self-reported psychological distress and risk of dementia-related mortality. METHOD: We included 31,043 eligible individuals between the ages of 60 and 80 years, at time of examination, from the CONOR (Cohort of Norway) database. They were followed for a period of 17.4 years (mean 11.5 years). The CONOR Mental Health Index, a seven-item self-report scale was used. A cut-off score equal to or above 2.15 on the scale denoted psychological distress. Cox regression was used to assess the association between psychological distress and risk of dementia-related mortality. RESULTS: Total number of registered deaths was 11,762 and 1118 (9.5%) were classified as cases of dementia-related mortality. We found that 2501 individuals (8.1%) had psychological distress, of these, 119 (10.6%) had concomitant dementia-related mortality. Individuals with psychological distress had an increased risk of dementia-related mortality HR = 1.52 (95% confidence interval (CI) 1.25-1.85) after adjusting for age, gender and education. The association remained significant although attenuated when implemented in a full adjusted model, including general health status, smoking, obesity, hypertension, diabetes and history of cardiovascular disease; hazard ratio, HR = 1.30 (95% CI 1.06-1.59). CONCLUSION: Our results indicate that psychological distress in elderly individuals is associated with increased risk of dementia-related mortality. Individuals at increased risk of dementia may benefit from treatments or interventions that lessen psychological distress, but this needs to be confirmed in future clinical studies.

Alcohol consumption in the elderly and risk of dementia related death--a Norwegian prospective study with a 17-year follow-up.

PURPOSE: The aim of this study was to determine the association between alcohol intake and risk of dementia related death, taking into account relevant confounding and mediating factors. MATERIALS AND METHODS: Data was obtained from a Norwegian prospective study with a 17-year follow-up. The study population comprised 25,635 participants aged between 60 and 80 years at the time of examination from the Cohort of Norway (CONOR). Cox regression was used to investigate the association between alcohol use and dementia related death. RESULTS: Nearly half (12,139) of the study population died during follow-up, of which 1,224 had a diagnosis of dementia on their death certificate. The risk of dementia related death was significantly higher among abstainers than among individuals that drank alcohol once per month (HR = 1.33, 95% CI = 1.14-1.56, p < 0.001, in a fully adjusted model). Respondents with missing information regarding alcohol consumption (representing 5% of the study population) had the highest risk of dementia related death (HR = 1.60, 95% CI = 1.28-2.00, p < 0.001) and also significantly higher mortality rates due to alcohol-related causes (HR = 1.41, 95% CI = 1.03-1.93, p = 0.031) and other causes (HR = 1.32, 95% CI = 1.21-1.43, p < 0.001), all compared to those drinking alcohol no more than once per month. CONCLUSION: These findings suggest that the risk of dementia related death is significantly higher among elderly abstainers than among those who drink alcohol, after adjusting for relevant confounders. However, care should be taken in interpretation of data due to missing information on drinking frequency, as this missing-group might have a large share of the heavy drinkers in the study cohort.

Interaction of Apolipoprotein E Genotypes, Lifestyle Factors and Future Risk of Dementia-Related Mortality: The Cohort of Norway (CONOR).

BACKGROUND/AIMS: Our aims were two-fold: firstly, to investigate the association and interaction between apolipoprotein E (ApoE), lifestyle risk factors and dementia-related mortality and, secondly, to examine if using dementia-related mortality yielded comparable risk estimates for the ApoE genotypes as reported in studies using a clinical dementia diagnosis as the end point. METHODS: We used a nested case-control study with 561 cases drawn from dementia deaths in the Cohort of Norway (CONOR) and 584 alive controls. RESULTS: ApoE ε4 carriers were at increased risk of dementia-related mortality compared to noncarriers [odds ratio (OR) 2.46, 95% confidence interval (CI) 1.93-3.13], and ε4 homozygotes were at particularly high risk (OR 7.86, 95% CI 3.80-13.8), while the ε2 type was associated with a lower risk. The highest risk of dementia-related mortality was found among ε4 carriers with more lifestyle risk factors (ε4 carriers who were smokers, hypertensive, physically inactive and diabetics) versus ε4 noncarriers without lifestyle risk factors (OR 15.4, 95% CI 4.37-52.4). The increased risk was additive, not multiplicative. CONCLUSIONS: Ensuring a healthy lifestyle is important to be able to prevent dementia in populations at large, but especially for ε4 carriers. Using dementia mortality gives comparable results for the ApoE-dementia association as studies using clinical dementia diagnoses.

Associations between Physical Activity in Old Age and Dementia-Related Mortality: A Population-Based Cohort Study.

BACKGROUND: Findings from the literature vary in relation to whether physical activity brings about less cognitive decline in old age. The present study investigated self-reported levels of physical activity in old age and its association with the risk of dementia-related mortality. METHODS: We included data from 31,086 subjects, between 65 and 80 years old, from the CONOR (Cohort of Norway) database. Cox regression analysis was used to estimate the risk of association. RESULTS: Taking part in 'light' (not causing perspiration or panting) activities of <3 h per week was associated with a decreased risk of dementia-related mortality, with a hazard ratio (HR) of 0.74 and a 95% confidence interval (CI) of 0.62-0.88, and of >3 h per week, with an HR of 0.61 and a 95% CI of 0.51-0.73. When taking part in 'hard' (causing perspiration or panting) activities, a similar risk (HR = 0.56; 95% CI 0.43-0.72) was observed for >3 h per week. Interestingly, the highest reduction in risk was seen for 'hard' activities of <3 h per week (HR = 0.50; 95% CI 0.41-0.61). CONCLUSION: Physical activity during leisure time in old age was associated with a lower risk of dementia-related mortality when compared to inactive individuals.

Age, education and dementia related deaths. The Norwegian Counties Study and The Cohort of Norway.

An inverse relationship between educational level and dementia has been reported in several studies. In this study we investigated the relationship between educational level and dementia related deaths for cohorts of people all born during 1915-39. The cohorts were followed up from adulthood or old age, taking into account possible confounders and mediating paths. Our study population comprised participants in Norwegian health examination studies in the period 1974-2002; The Counties Study and Cohort of Norway (CONOR). Dementia related deaths were defined as deaths with a dementia diagnosis on the death certificate and linked using the Cause of Death Registry to year 2012. The study included 90,843 participants, 2.06 million person years and 2440 dementia related deaths. Cox regression was used to assess the association between education and dementia related deaths. Both high and middle educational levels were associated with lower dementia related death risk compared to those with low education when follow-up started in adulthood (35-49 years, high versus low education: HR=0.68, 95% confidence interval (CI) 0.50-0.93; 50-69 years, high versus low education: HR=0.52, 95% CI 0.34-0.80). However, when follow-up started at old age (70-80 years) there was no significant association between education and dementia related death. Restricting the study population to those born during a five-year period 1925-29 (the birth cohort overlapping all three age groups), gave similar main findings. The protective effects found for both high and middle educational level compared to low education were robust to adjustment for cardiovascular health and life style factors, suggesting education to be a protective factor for dementia related death. Both high and middle educational levels were associated with decreased dementia related death risk compared with low educational level when follow-up started in adulthood, but no association was observed when follow-up started at old age.

Midlife vascular risk factors and their association with dementia deaths: results from a Norwegian prospective study followed up for 35 years.

There is growing evidence that midlife risk factors for vascular disease also are risk factors for dementia, but there is still need for long-term observational studies to address this. Our objective was to investigate the association of midlife vascular disease risk factors with dementia death. Participants were included in The Norwegian Counties Study (NCS) in the period 1974-78, aged 35-50 years at baseline. Information from NCS was linked with the Cause of Death Registry through the year 2009 using the unique personal identification number. The study included 48,793 participants, 1.5 million person years and 486 dementia deaths (187 Alzheimer's; 299 non-Alzheimer's dementia). Cox regression for cause-specific hazards was used. Dementia death was associated with increased total cholesterol levels (>7.80 vs. <5.20 mmol/l: HR=2.01, 95% confidence interval 1.37-2.93); diabetes (HR=2.43, 95% CI 1.40-4.32) and low body mass index (<20 kg/m(2) vs. 20-25 kg/m(2): HR=1.76, 95% CI 1.15-2.68) in midlife. The associations remained after adjustment for other vascular risk factors and educational level. Smoking status or blood pressure in midlife was not significantly associated with risk of dementia death, although the results indicate a possible increased risk in heavy smokers. People suffering from high cholesterol levels, diabetes or underweight in midlife are at increased risk of dying from or with dementia later in life. Our findings add to previous results suggesting that intervention in midlife may be important. To better understand the mechanisms involved in the associations between midlife underweight, diabetes, and elevated cholesterol level and late-life dementia death, these links need to be further investigated.