Contrary to prior findings, no evidence was found to support a protective association between leisure activity and risk of dementia.
Andrew Sommerlad, PhD
Leisure activity declines shortly before diagnosis of dementia, according to findings from a recent study published in Neurology. Contrary to other recent studies with shorter follow-up times, no evidence was found to support a protective association between leisure activity and risk of dementia.
Associations between leisure activity and dementia only became significant when data were assessed less than 10 years prior to dementia diagnosis. At a mean age 65.7 years, those with higher participation in leisure activities were less likely to develop dementia (hazard ratio [HR], 0.82; 95% CI, 0.69–0.98). Earlier participation in leisure activity was not associated with dementia, with an HR of 0.92 at a mean age of 55.8 years (95% CI, 0.79–1.06), 18 years prior to dementia diagnosis.1
Change in leisure activity was found to have a greater association with risk of dementia than initial frequency. For 1 standard deviation decline in leisure activity, the HR for the next 8.3 years was 1.35 (95% CI, 1.10–1.66) when compared to those whose leisure activity remained low, and no significant difference was observed in the incidence of dementia between groups whose level of leisure activity remained low, medium, or high, as the data were stratified.
Principal investigator Andrew Sommerlad, PhD, principal research fellow, Division of Psychiatry, Faculty of Brain Sciences, University College London, told NeurologyLive, “symptoms of dementia come on gradually, probably over several years as damage occurs in the brain. While memory loss is the typical symptom, a range of behavioral and neuropsychiatric symptoms can be early presenting features such as apathy or deficits in social cognition domains.”
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Data were collected from 8280 people who participated in at least 1 of 3 periods of collection in the Whitehall II prospective cohort study: 1997–99, 2002–04, or 2007–09. Of this group, 360 (4.35%) developed dementia (mean age at diagnosis, 76.2 years; incidence rate, 2.4 per 1,000 person-years) and 1111 (13.42%) died by March 2017. Leisure activity was assessed by questionnaire of frequency of participation in activities such as gardening, clubs, associations, religious activities, etc. Types of leisure activities had no significant association with dementia, although physical activity was not assessed.
Sommerlad and colleagues did not find evidence of any causal relationship between leisure activity and dementia, contrary to other studies, most of which had fewer than 6 years of follow-up. These associations were likely due to reverse association, as shorter follow-up times may only have observed a decline in activity preceding diagnosis.
The authors did not investigate different subtypes of dementia, which may show differences in association with leisure activity. Sensitivity analyses and use of multiple imputation to account for missing data confirmed the primary analyses and only the change in leisure activities yielded a significant incidence of dementia.
Given this new lens to look at leisure activity through, Sommerlad said that “it is important for physicians to ask about participation in leisure activities and other complex activities of daily living, and to get the objective view of a family member if possible. Reduction in these potentially indicates functional decline due to dementia, but there are other causes like physical or mental health problems which could impair a person’s ability to maintain social activity.”
Large, long-term, controlled interventional trials, although difficult to implement, could provide stronger evidence of a causal relationship between lifestyle and dementia. In an accompanying editorial, Victor W. Henderson, MD, MS, and Merrill F. Elias, PhD, MPH, noted that an ongoing trial, the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability, is investigating the effect of implementing diet, cognitive training, and amelioration of vascular comorbidity on decreasing the development of dementia. They noted that preliminary results show “statistically significant but clinically unimportant cognitive improvement” equivalent to 0.02 standard deviations per year.2
Although dementia is currently only diagnosed when symptoms clearly interfere with daily life, Sommerlad urged that we “get better at detecting the subtle early changes of dementia through careful history-taking and perhaps in the future through technological approaches like digital monitoring of activity.”