Whitehall II calls into question protective association of leisure activities and dementia

The relationship between leisure activity and dementia risk may be prodromal rather than protective, with declines in leisure activities the result rather than the cause of early dementia, an analysis of Whitehall II cohort participants suggested.

“In this large longitudinal study, participation in leisure activities at mean age 56 years was not associated with incidence of dementia over the subsequent 18 years,” reported Andrew Sommerlad, PhD, of University College London, and coauthors.

“Associations were only evident when leisure activity was assessed at older ages, with less than 10 years between assessment of leisure activities and diagnosis of dementia,” they wrote in Neurology.

For each standard deviation of higher leisure activity score, dementia risk was 8% lower when follow-up was 18 years (HR 0.92, 95% 0.79- 1.06) and 12% lower when follow-up was 13 years (HR 0.88, 95% CI 0.76-1.03). It was 18% lower at 8.3 years follow-up, when activity participation was assessed at mean age 66 (HR 0.82, 95% CI 0.69-0.98).

People whose leisure activity declined over the full study had increased dementia risk: for each standard deviation decline in leisure activity participation, HR for incident dementia was 1.35 (95% CI 1.10-1.66).

No association was seen for people with low activity throughout the follow-up period. No consistent associations were found for participation in specific types of leisure activities.

“These results do not support the hypothesis that leisure activity participation can lower dementia risk, but suggest instead that reduction in activity participation is an indication of possible prodromal dementia,” Sommerlad and colleagues said.

“Our results cannot rule out the possibility that leisure activity participation after 65 years confers protection against dementia, or that lack of leisure activity or reduction in such activity at a vulnerable time leads to people being more likely to develop dementia,” they added. “However, there is no compelling mechanism to explain this interpretation of the results, given the known long preclinical period of dementia.”

In an accompanying editorial, Victor Henderson, MD, MS, of Stanford University, and Merrill Elias, PhD, MPH, of the University of Maine in Orono, noted that the association between leisure activity and dementia seen only over shorter follow-up periods “might mean that leisure activity undertaken closer to the onset of dementia is more protective than leisure activity pursued more remotely.”

“However, this supposition is challenged by other results,” they wrote. “The risk of dementia among cohort members whose leisure activity declined during the years between the first and third assessments was greater than the dementia risk of those whose leisure activity was low at both times.” An alternative possibility is that reduced leisure activity is an early symptom of nascent neurodegeneration, they added.

Leisure activity is thought to boost cognitive reserve through mental and physical activity and social engagement. Associations between leisure activity and cognitive impairment of varying degrees have been described within 10 years of dementia diagnosis, though the pathologic changes of dementia typically begin earlier, particularly in Alzheimer’s disease.

Whether protective effects of leisure activity on dementia risk occur after the onset of neurodegeneration and whether the changes of neurodegeneration that lead to apathy and other motivational and behavioral changes make leisure activity unsustainable is an unresolved question.

Sommerlad and colleagues included evaluations in the prospective longitudinal Whitehall II study from 1997-1999, 2002-2004, and 2007-2009, with follow-up until March 2017. Dementia incidence was obtained from national registers, and primary analyses were based on complete cases (n=6,050; 69% male, 91% white, dementia cases=247).

To describe leisure activities, participants reported their frequency of reading, listening to music, using a home computer for fun, education/classes, organizational activity, cultural visits, holding office, table games, gardening, home projects, making things (such as drawing or pottery), religious activity, socializing, and visiting others.

There are reasons to remain cautious about the conclusions of this study, the editorialists noted. The study did not consider dementia subtypes; leisure activity might be protective for one type but not another, they pointed out. Intensity of leisure activities was not accounted for, and sports and exercise activities were excluded.

In addition, misclassification of dementia and forms of cognitive impairment in the national registers may bias results, and young adult and childhood activities were not included.

“Leisure activity holds intrinsic value for relaxation and pleasure. Even if withdrawal from leisure activity does not itself contribute to cognitive decline, reduced activity may still portend cognitive impairment,” Henderson and Elias noted.

“The role of leisure activity in dementia prevention is far from settled,” they observed. “Large, long duration, randomized controlled trials could provide even stronger evidence of any causal relationship. Several such trials, planned or underway in the U.S. and other countries, focus on lifestyle interventions,” they noted.

“In concert with other findings, the Sommerlad et al study results raise new questions on how we should advise our patients on dementia prevention,” they added. “Midlife and late-life leisure activity certainly does no harm, but its role in dementia prevention is not yet clear. There is more work to be done.”

  1. The relationship between leisure activity and dementia risk may be prodromal rather than protective, with decline in leisure activities the result rather than the cause of early dementia, an analysis of Whitehall II cohort participants suggested.

  2. Participation in leisure activities at age 56 was not associated with dementia incidence over the next 18 years. Associations between leisure activity and dementia were evident only when leisure activity was assessed at older ages.

Paul Smyth, MD, Contributing Writer, BreakingMED™

The Whitehall II study is supported by grants from the U.S. NIH, the U.K. Medical Research Council, and British Heart Foundation.

Sommerlad reported funding from Wellcome Trust.

Henderson and Elias reported no disclosures relevant to the manuscript.

Cat ID: 361

Topic ID: 82,361,361,192,362,925