Danielle Laurin

Omega-3 fatty acids and risk of cognitive impairment and dementia.

It has been suggested that the dietary intake of omega-3 polyunsaturated fatty acids could be inversely related to the risk of dementia and cognitive decline. This analysis examined the association between plasma concentration of omega-3 polyunsaturated fatty acids and prevalence and incidence of cognitive impairment and dementia. Data are reported on subjects 65 years or older who had a complete clinical evaluation at the first two waves (1991-1992 and 1996-1997) of the Canadian Study of Health and Aging. Main outcome measures were cognitive impairment and dementia by mean relative plasma concentrations of fatty acids in the phospholipid fraction at baseline. Results were adjusted for age, sex, education, smoking, alcohol intake, body mass index, history of cardiovascular disease, and apolipoprotein E e4 genotype. In the cross-sectional analysis, no significant difference in omega-3 polyunsaturated fatty acid concentrations was observed between controls and both prevalent cases of cognitive impairment and dementia. In the prospective analysis, a higher eicosapentaenoic acid (p < 0.01) concentration was found in cognitively impaired cases compared to controls while higher docosahexaenoic acid (p < 0.07), omega-3 (p < 0.04) and total polyunsaturated fatty acid (p < 0.03) concentrations were found in dementia cases. These findings do not support the hypothesis that omega-3 polyunsaturated fatty acids play a protective role in cognitive function and dementia.

Omega-3 fatty acids and risk of dementia: the Canadian Study of Health and Aging

BACKGROUND Omega-3 polyunsaturated fatty acids (n-3 PUFAs) may protect against dementia, although epidemiologic studies have yielded inconclusive results. Fish is the main dietary source of n-3 PUFAs and is sometimes contaminated with mercury. This neurotoxicant may modify the association with dementia. OBJECTIVE We evaluated the association of erythrocyte membrane total n-3 PUFAs, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and blood mercury with the incidence of dementia and Alzheimer disease (AD) in the Canadian Study of Health and Aging (CSHA) with adjustment for confounders including apolipoprotein E epsilon4 (APOE epsilon4) status. DESIGN The CSHA is a cohort study of a representative sample of persons aged > or =65 y, conducted from 1991 to 2002. A subsample of 663 nondemented CSHA subjects with a complete clinical examination, blood samples, and follow-up information was eligible for prospective analyses on laboratory measurements. Of these, 149 were incident cases of dementia, including 105 with AD. RESULTS In adjusted Cox regression models with age as the time scale, there were no associations between total n-3 PUFAs, DHA, or EPA and dementia or AD. In contrast, a mercury concentration in the highest quartile was associated with a reduced risk of dementia (hazard ratio: 0.53; 95% CI: 0.33, 0.88). However, significant risk reductions were limited to subjects with concentrations of both n-3 PUFAs and mercury that were above the median. There was no modification of risk by APOE epsilon4 status. CONCLUSIONS No associations between n-3 PUFAs and dementia or AD were found. The results regarding mercury may indicate a spurious association.

Potentially inappropriate prescriptions for older patients in long-term care

BackgroundInappropriate medication use is a major healthcare issue for the elderly population. This study explored the prevalence of potentially inappropriate prescriptions (PIPs) in long-term care in metropolitan Quebec.MethodsA cross sectional chart review of 2,633 long-term care older patients of the Quebec City area was performed. An explicit criteria list for PIPs was developed based on the literature and validated by a modified Delphi method. Medication orders were reviewed to describe prescribing patterns and to determine the prevalence of PIPs. A multivariate analysis was performed to identify predictors of PIPs.ResultsAlmost all residents (94.0%) were receiving one or more prescribed medication; on average patients had 4.8 prescribed medications. A majority (54.7%) of treated patients had a potentially inappropriate prescription (PIP). Most common PIPs were drug interactions (33.9% of treated patients), followed by potentially inappropriate duration (23.6%), potentially inappropriate medication (14.7%) and potentially inappropriate dosage (9.6%). PIPs were most frequent for medications of the central nervous system (10.8% of prescribed medication). The likelihood of PIP increased significantly as the number of drugs prescribed increased (odds ratio [OR]: 1.38, 95% confidence interval [CI]: 1.33 – 1.43) and with the length of stay (OR: 1.78, CI: 1.43 – 2.20). On the other hand, the risk of receiving a PIP decreased with age.ConclusionPotentially inappropriate prescribing is a serious problem in the highly medicated long-term care population in metropolitan Quebec. Use of explicit criteria lists may help identify the most critical issues and prioritize interventions to improve quality of care and patient safety.

Is Complexity of Work Associated with Risk of Dementia? The Canadian Study of Health and Aging

The authors evaluated the association of complexity of work with data, people, and things with the incidence of dementia, Alzheimers disease, and vascular dementia in the Canadian Study of Health and Aging, while adjusting for work-related physical activity. The Canadian Study of Health and Aging is a 10-year population study, from 1991 to 2001, of a representative sample of persons aged 65 years or older. Lifetime job history allowed application of complexity scores and classification of work-related physical activity. Analyses included 3,557 subjects, of whom 400 were incident dementia cases, including 299 with Alzheimers disease and 93 with vascular dementia. In fully adjusted Cox regression models, high complexity of work with people or things reduced risk of dementia (hazard ratios were 0.66 (95% confidence interval: 0.44, 0.98) and 0.72 (95% confidence interval: 0.52, 0.99), respectively) but not Alzheimers disease. For vascular dementia, hazard ratios were 0.36 (95% confidence interval: 0.15, 0.90) for high complexity of work with people and 0.50 (95% confidence interval: 0.25, 1.00) for high complexity of work with things. Subgroup analyses according to median duration (23 years) of principal occupation showed that associations with complexity varied according to duration of employment. High complexity of work appears to be associated with risk of dementia, but effects may vary according to subtype.

Ankle-to-Brachial Index and Dementia The Honolulu-Asia Aging Study

Background— Measurement of the ankle-to-brachial index (ABI) is a noninvasive test to assess peripheral arterial disease. A low ABI is a strong correlate of cardiovascular disease and subsequent mortality. Evidence indicates the existence of vascular components in the pathogenesis of dementia. Here, we examine the association of ABI with dementia and subtypes. Methods and Results— Data are from the Honolulu-Asia Aging Study (HAAS), a prospective community-based study of 3734 Japanese American men 71 to 93 years of age at baseline in 1991 to 1993. The analysis included 2588 men who were free of dementia at the first assessment, had an ABI measure, and were examined up to 2 more times for dementia between 1994 and 1999. The sample included 240 incident cases of dementia (144 of Alzheimers disease, 46 of vascular dementia, and 50 of dementia of other causes). Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated from Cox proportional-hazards models with age as the time scale after adjustment for education, year of birth, high blood pressure, body mass index, diabetes mellitus, cholesterol concentration, smoking status, alcohol consumption, and apolipoprotein E &egr;4 allele. A low ABI was associated with an increased risk of dementia and vascular dementia (HR, 1.66; 95% CI, 1.16 to 2.37; and HR, 2.25; 95% CI, 1.07 to 4.73, respectively). ABI was weakly associated with Alzheimers disease (HR, 1.57; 95% CI, 0.98 to 2.53), particularly in the apolipoprotein E &egr;4 carriers (HR, 1.43; 95% CI, 1.02 to 1.96). Conclusions— These results suggest that ABI, a measure of atherosclerosis, is associated with the incidence of total dementia, vascular dementia, and Alzheimers disease in carriers of the apolipoprotein E &egr;4 allele.

Nonsteroidal anti-inflammatory drug use and the risk of cognitive impairment and Alzheimer's disease.

Some observational studies have established an association between exposure to nonsteroidal anti‐inflammatory drugs (NSAIDs) and a decreased risk of subsequently developing Alzheimers disease (AD). Mild cognitive impairment or cognitive impairment, not dementia (CIND) is more likely to convert to AD, and no specific preventive method is currently available. The objective of this study was to determine the association of NSAID use in 5276 cognitively normal subjects of the Canadian Study of Health and Aging, a 10‐year population‐based cohort study, with the incidence of CIND, AD, and all‐cause dementia.

Influence of diets containing cow's milk or soy protein beverage on plasma lipids in children with familial hypercholesterolemia.

The present article summarizes the effects of diets containing either cows milk or soy protein beverage on plasma lipids and lipoproteins in children with familial hypercholesterolemia. After a stabilization period of 6 weeks without any hypolipemic medication, 10 subjects aged 6-12 years were randomly assigned to either cows milk or soy protein beverage with subsequent crossover after a washout period, each of 4 weeks duration. During the experimental periods, subjects were fed diets containing 20% of energy as protein, of which 35% was from cows milk protein or soy protein isolate, 28% of energy as fat with a polyunsaturated:monounsaturated:saturated fat ratio of 1:3:3, and less than 200 mg/day of cholesterol. The soy protein beverage, compared to cows milk, induced significant reductions in plasma triglycerides and very-low-density lipoprotein cholesterol, as well as a significant increase in high-density lipoprotein cholesterol, indicating that consumption of soy protein beverage may be beneficial for the prevention of coronary heart disease in children with familial hypercholesterolemia.

Vascular risk factors and cognitive functions in nondemented elderly individuals.

Background: The brain-at-risk stage is the earliest phase of the vascular cognitive impairment continuum and includes individuals with vascular risk factors (VRF). However, there is still no clear definition of this concept. The aim of the study is to characterize the neuropsychological profile of elderly individuals by 3 levels of VRF. Methods: This is a cross-sectional analysis of the Canadian Study of Health and Aging baseline data; 577 nondemented elderly individuals ≥65 years old were divided into 3 groups: reference group (0 VRF; n = 82); intermediate brain-at-risk group (1-2 VRF; n = 360); high brain-at-risk group (≥3 VRF; n = 135). A principal component analysis (PCA) and univariate/multivariate analyses of variance were performed to examine the relationships between the groups and various cognitive measures. Main findings: The PCA produced a 2-component solution (1) executive/psychomotor functions including measures of abstraction and (2) verbal memory. The high brain-at-risk group performed significantly worse than the reference group on the first component. Conclusions: Elderly individuals presenting with ≥3 VRF are more impaired on measures of executive functions/ processing speed than participants without any VRF.

Plasma polychlorinated biphenyl and organochlorine pesticide concentrations in dementia: The Canadian Study of Health and Aging

BACKGROUND Even though polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides are recognized as neurotoxicants, few studies have investigated their associations with dementia. Here, we assess associations of plasma PCB and OC pesticide concentrations with all-cause dementia and Alzheimers disease (AD). METHODS Analyses are based on data from the Canadian Study of Health and Aging, a population-based study of men and women aged 65+ years at baseline. PCB and OC pesticide concentrations were measured in 2023 participants who had complete clinical evaluations and blood samples; 574 had dementia, including 399 cases of AD. Concentrations were log-transformed and used as continuous variables in logistic regression models to assess their individual associations with dementia and AD. RESULTS After adjustment for blood collection period, total plasma lipids, age, sex, education, apolipoprotein E e4 allele (ApoE4), tobacco and alcohol use, rural/urban residence, and comorbidities, elevated plasma PCB concentrations were not associated with increased prevalence of dementia and AD. Elevated concentrations of some OC pesticides and metabolites such as hexachlorobenzene, cis-nonachlor and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane were significantly associated with a reduced prevalence of dementia. A significant reduced prevalence of AD was also observed with elevated hexachlorobenzene concentrations. Other OC pesticides and metabolites were not associated with the prevalence of dementia or AD. No effect modification by sex and ApoE4 was observed for either dementia or AD. CONCLUSIONS Elevated plasma PCB and OC pesticide concentrations were not associated with higher prevalence of all-cause dementia and AD. The possibility of modest reductions in prevalence with specific OC pesticides remains to be further investigated given the cross-sectional design of this study.

Thyroid function and cognition in the euthyroid elderly: A case–control study embedded in Quebec longitudinal study – NuAge

It is presently unclear whether there is a significant association between thyroid function and cognitive decline in euthyroid elderly. This case-control study aimed to examine serum thyroid stimulating hormone (TSH), total thyroxine, free thyroxine, total triiodothyronine, and free triiodothyronine in relation to cognitive decline over a 3-year period in a subsample of 62 participants (31 pairs) aged 67 years and over at baseline from the NuAge study (Quebec longitudinal study). They were matched for age, sex and global cognition. In conditional regression logistic models, there was no significant association between any thyroid function indices and the 3-year risk of cognitive decline as measured with the Modified Mini-Mental State Examination (3MS). TSH and thyroid hormones do not appear to be associated with cognitive decline in euthyroid older persons. These findings need confirmation given the small number of pairs of subjects.