The impact of seasons on cognitive function, neuropsychiatric symptoms, and activities of daily living in patients with Alzheimer’s disease

BACKGROUND: This study explored the correlation between seasonal changes and cognitive function, neuropsychiatric symptoms, and activities of daily living (ADL) in patients with Alzheimer's disease (AD). METHODS: Eighty AD patients completed a 12-month follow-up with assessments every season. Mini-Mental State Examination (MMSE), Neuropsychiatric Inventory (NPI), Basic and Instrumental ADL (BADL, IADL) were assessed. RESULTS: Total MMSE scores in spring (β = 0.812, 95% CI: 0.101-1.522, p = 0.025), summer (β = 1.049, 95% CI: 0.248-1.851, p = 0.010), and autumn (β = 1.119, 95% CI: 0.425-1.812, p = 0.002) were higher than in winter. Total NPI scores were higher in winter than in summer (β = 1.754, 95% CI: 0.014-3.493, p = 0.048) and autumn (β = 1.492, 95% CI: 0.010-2.975, p = 0.049). NPI caregiver distress scores in winter were higher than in summer (β = 1.025, 95% CI: 0.111-1.939, p = 0.028) and autumn (β = 1.502, 95% CI: 0.723-2.281, p < 0.001). BADL scores in winter were higher than in summer (β = 0.919, 95% CI: 0.310-2.975, p = 0.003) and autumn (β = 1.046, 95% CI: 0.528-1.564, p < 0.001). IADL scores in winter and spring were higher than in summer (winter: β = 0.760, 95% CI: 0.045-1.475, p = 0.037; spring: β = 0.697, 95% CI: 0.070-1.323, p = 0.030) and autumn (winter: β = 1.153, 95% CI: 0.545-1.761, p < 0.001; spring: β = 1.089, 95% CI: 0.373-1.805, p = 0.003). CONCLUSIONS: .Seasonal variations influence AD manifestations, with winter as a critical period.