Prevalence of Sinusitis Detected by Magnetic Resonance Imaging in Subjects with Dementia or Alzheimer’s Disease

Background: It has been reported that periodontitis is associated with Alzheimer’s disease. However, the association between paranasal sinusitis and Alzheimer’s disease has not been studied, although olfactory dysfunction frequently precedes the progress of dementia or Alzheimer’s disease. Methods: We studied 783 patients (283 men, 500 women; mean age 77.0 ± 7.9 years) who visited the Center for Comprehensive Care and Research on Memory Disorders, National Center for Geriatrics and Gerontology, and 2139 control subjects who participated in a population-based study conducted by the National Institute for Longevity Sciences – Longitudinal Study of Aging (NILS–LSA) in Japan. Sinusitis was evaluated using magnetic resonance imaging (MRI) according to the Lund–Mackay scoring system. A sinusitis score of ≥ 4 was classified as positive and a score of ≤ 3 was classified as negative. Results: The prevalence of positive sinusitis was 6.3% in patients with a mini-mental state examination (MMSE) score of < 24 (n = 507), and 5.7% in patients with Alzheimer’s disease (n = 280). The rate of positive sinusitis was7.2% in the control group. The prevalence of sinusitis was not significantly different between normal controls and patients with dementia or Alzheimer’s disease after adjustments for age and sex. The rate of positive sinusitis was higher in male than in female subjects in both groups. Conclusion: The prevalence of sinusitis in patients with Alzheimer’s disease or dementia was not higher than in the general population.