Comorbidities and health-care use prior to early-onset Alzheimer's disease: A population-based case-control study.

INTRODUCTION

We examined whether comorbidities and health-care use differ between individuals later diagnosed with early-onset Alzheimer's disease (EOAD) and matched controls during the 15 years preceding diagnosis.

METHODS

This population-based case-control study included 407 EOAD patients diagnosed at two Finnish university hospitals (2010-2021), and 4035 age- and sex-matched controls. Prior diagnoses and health-care visits were obtained from nationwide registers.

RESULTS

EOAD patients had higher prevalence of vertigo (5.9% vs. 2.1%, p < 0.001), depression (5.7% vs. 2.3%, p < 0.001), headache (4.9% vs. 1.6%, p < 0.001), delirium (1.5% vs. 0.1%, p < 0.001), brain injuries (2.9% vs. 0.9%, p = 0.002), thyroid disorders (2.5% vs. 0.8%, p = 0.008), alcohol-related disorders (3.4% vs. 1.4%, p = 0.009), epilepsy (2.2% vs. 0.7%, p = 0.009), strokes (4.4% vs. 2.0%, p = 0.008), and otorhinolaryngologic diseases (5.2% vs. 2.9%, p = 0.027) 1-5 years before diagnosis. Only otorhinolaryngologic diseases (4.7% vs. 2.1%, p = 0.036) differed 6 to 10 years prior, whereas no differences were seen 11 to 15 years before diagnosis. Hypertension and dyslipidemia showed no between-group differences. Health-care use increased markedly from year before EOAD diagnosis.

DISCUSSION: EOAD is preceded by recognizable patterns of morbidity and increased health-care use, which may support earlier detection.