Family history and modifiable risk factors in early‐onset Alzheimer’s disease in southern Brazil

• Published in: Alzheimer's & dementia Vol. 19; no. S23
• Main Authors: de Albuquerque, Ana Letícia Amorim, Franco, Alvaro de Oliveira, Chaves, Marcia L Fagundes, Castilhos, Raphael Machado
• Format: Journal Article
• Language: English
• Published: 01-12-2023
• ISSN: 1552-5260; 1552-5279
• DOI: 10.1002/alz.078562

Background
Alzheimer’s disease (AD) represents a burdensome health condition worldwide and has a highly clinical heterogeneity. In particular, the early‐onset presentations may be related to different risk factors and underlying pathological mechanisms. We aimed to compare the frequency of modifiable risk factors/family history of dementia in a sample of AD from a tertiary memory outpatient clinic in Southern Brazil.
Method
We reviewed the clinical data of patients clinically diagnosed with AD at the dementia outpatient clinic at the Hospital de Clínicas de Porto Alegre, Brazil, between 2014 and 2022. We collected sociodemographic, clinical, family history, and the presence of seven modifiable risk factors for dementia: hypertension, diabetes, alcohol abuse, tobacco use, traumatic brain injury, hearing loss and previous psychiatric illness. Differences between early (< 65 years) and late‐onset AD were analyzed by Chi squared and Mann‐Whitney tests, with significance defined as p<0.05. All analyses were made in the R.
Results
A total of 145 patients were evaluated, 96 (66.2%) female, mostly (80.7%) white and median (interquartile range, IQR) of 76 (69‐80) years in the first evaluation. Of these, 40 (27.6%) had early‐onset presentation, with age at onset of 59.3 (52.4 ‐ 63) years. The early‐onset group presented a higher frequency of family history of dementia with an autosomal dominant pattern, 7 (17.5%) vs 0 (p = 0.011), with two patients being diagnosed with PSEN1 mutations, and worse scores in Mini Mental State Examination (p = 0.034) at the first evaluation. The groups did not differ in years of formal education or disease duration at the first appointment. Except for a higher frequency of hypertension in the late‐onset group, 68 (64.8%) vs 18 (45%), p = 0.048, there was no difference in the other risk factors (Table 1).
Conclusion
In our sample, the profile of risk factors was similar between early‐ and late‐onset AD presentations, but the early‐onset patients had a higher frequency of autosomal dominant dementia family history. Our results suggest that in our sample the genetic and modifiable risk factors are both associated with early‐onset presentations.