Recent findings suggest that a rich social network may decrease the risk of developing dementia. The authors hypothesized that such a protective effect may be due to social interaction and intellectual stimulation. To test this hypothesis, data from the 1987–1996 Kungsholmen Project, a longitudinal population-based study carried out in a central area of Stockholm, Sweden, were used to examine whether engagement in different activities 6.4 years before dementia diagnosis was related to a decreased incidence of dementia. Dementia cases were diagnosed by specialists according to Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, criteria. After adjustment for age, sex, education, cognitive functioning, comorbidity, depressive symptoms, and physical functioning at the first examination, frequent (daily-weekly) engagement in mental, social, or productive activities was inversely related to dementia incidence. Adjusted relative risks for mental, social, and productive activities were 0.54 (95% confidence interval (CI): 0.34, 0.87), 0.58 (95% CI: 0.37, 0.91), and 0.58 (95% CI: 0.38, 0.91), respectively. Similar results were found when these three factors were analyzed together in the same model. Results suggest that stimulating activity, either mentally or socially oriented, may protect against dementia, indicating that both social interaction and intellectual stimulation may be relevant to preserving mental functioning in the elderly.

Background: There is accumulating evidence in the literature that leisure engagement has a beneficial effect on dementia. Most studies have grouped activities according to whether they were predominantly mental, physical or social. Since many activities contain more than one component, we aimed to verify the effect of all three major components on the dementia risk, as well as their combined effect. Methods: A mental, social and physical component score was estimated for each activity by the researchers and a sample of elderly persons. The correlation between the ratings of the authors and the means of the elderly subjects’ ratings was 0.86. The study population consisted of 776 nondemented subjects, aged 75 years and above, living in Stockholm, Sweden, who were still nondemented after 3 years and were followed for 3 more years to detect incident dementia cases. Results: Multi-adjusted relative risks (RRs) of dementia for subjects with higher mental, physical and social component score sums were 0.71 (95% CI: 0.49–1.03), 0.61 (95% CI: 0.42–0.87) and 0.68 (95% CI: 0.47–0.99), respectively. The most beneficial effect was present for subjects with high scores in all or in two of the components (RR of dementia = 0.53; 95% CI: 0.36–0.78). Conclusions: These findings suggest that a broad spectrum of activities containing more than one of the components seems to be more beneficial than to be engaged in only one type of activity.

The concept of brain reserve refers to the ability to tolerate the age-related changes and the disease related pathology in the brain without developing clear clinical symptoms or signs. A considerable body of biological research has documented that

Objective: To explore the associations of low serum levels of vitamin B₁₂ and folate with AD occurrence. Methods: A population-based longitudinal study in Sweden, the Kungsholmen Project. A random sample of 370 nondemented persons, aged 75 years and older and not treated with B₁₂ and folate, was followed for 3 years to detect incident AD cases. Two cut-off points were used to define low levels of vitamin B₁₂ (≤150 and ≤250 pmol/L) and folate (≤10 and ≤12 nmol/L), and all analyses were performed using both definitions. AD and other types of dementia were diagnosed by specialists according to DSM-III-R criteria. Results: When using B₁₂ ≤150pmol/L and folate ≤10 nmol/L to define low levels, compared with people with normal levels of both vitamins, subjects with low levels of B₁₂or folate had twice higher risks of developing AD (relative risk [RR] = 2.1, 95% CI = 1.2 to 3.5). These associations were even stronger in subjects with good baseline cognition (RR = 3.1, 95% CI = 1.1 to 8.4). Similar relative risks of AD were found in subjects with low levels of B₁₂or folate and among those with both vitamins at low levels. A comparable pattern was detected when low vitamin levels were defined as B₁₂ ≤250 pmol/L and folate ≤12 nmol/L. Conclusions: This study suggests that vitamin B₁₂ and folate may be involved in the development of AD. A clear association was detected only when both vitamins were taken into account, especially among the cognitively intact subjects. No interaction was found between the two vitamins. Monitoring serum B₁₂ and folate concentration in the elderly may be relevant for prevention of AD.