Dementia: healthier lifestyle may counter genetic risk

  • Lourida I & al.
  • JAMA
  • 14 Jul 2019

  • International Clinical Digest
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Takeaway

  • A healthier lifestyle may be able to attenuate elevated genetic risk for dementia in older adults.

Why this matters

  • Lack of interventions to prevent, treat dementia, coupled with aging of the population.

Key results

  • Dementia incidence was higher among older adults with high vs low genetic risk (1.23% vs 0.63%; adjusted HR, 1.91; P<.001>
  • Incidence roughly tripled with high genetic risk+unfavourable lifestyle vs low genetic risk+favourable lifestyle (1.78% vs 0.56%; HR, 2.83; P<.001>
  • No interaction between genetic risk, lifestyle factors (P=.99).
  • Among older adults with high genetic risk, dementia incidence lower with:
    • Favourable vs unfavourable lifestyle (1.13% vs 1.78%; HR, 0.68; P=.008).
    • Intermediate vs unfavourable lifestyle (1.18% vs 1.78%; HR, 0.71; P=.03).

Study design

  • Retrospective cohort study: 196,383 adults of European ancestry aged 60-73 years without cognitive impairment, dementia (UK Biobank study).
    • Polygenic dementia risk score: low (lowest quintile), intermediate (quintiles 2-4), high (highest quintile).
    • Weighted healthy lifestyle score: favorable, intermediate, unfavourable (based on no current smoking, regular physical activity, healthy diet, moderate alcohol consumption).
  • Main outcome: all-cause dementia during median 8.0-year follow-up.
  • Funding: UK Biobank resource.

Limitations

  • Lifestyle left up to participants.
  • Unmeasured, residual confounding.
  • Some dementia cases potentially missed.
  • Unknown generalisability.