Novel risk factors and comprehensive assessment of Alzheimer’s disease patients: case control hospital-based study

Abstract Background Alzheimer’s disease (AD) is a growing health concern, despite the significant research, the current understanding of AD risk factors is incomplete. The aim of this study was to identify novel risk factors such as sleep disturbances, diet, hypoxia, hearing impairment and exposure to pollutants that may contribute to the development or progression of Alzheimer disease and improve early detection and prevention strategies by assessing serum neurofilament light chain (sNFLc). Methods This case control hospital-based study was carried out at the Neurology outpatient clinics at Zagazig University Hospitals during the period from May 2022 to October 2023, Patients aged 50 years and older with different neurological disorders were screened using Montreal cognitive assessment (MoCA) in order to pick up suspected cases of AD dementia, Five hundreds and ten patients were found to have different types of dementia, forty three of them fulfilled the criteria for Alzheimer disease diagnosis according to fifth edition of the diagnostic and statistical manual of mental disorders (DSM-5) and the eleventh edition of international classification of disease (ICD-11).These forty-three patients were included in the study in addition to forty-three healthy individuals with age matched who served as control group. All patients underwent a thoroughdetailed medical history including the risk factors questionnaire, physical and neurological examination. Also, the following scales were done as Instrumental Activities of Daily Living Scale (IADLs),Quality of Life in Alzheimer’s Disease scale 13-items Questionnaire (QoL) and Global Deterioration Scale (GDs) in Alzheimer’s Disease as well as laboratory specially sNFLc and radiographic tests. Results The patients’ groups consisted of 25 males (58.1%) and 18 females (41.9%); their mean age was 68.16 ± 7.32 years. The control group consisted of 17 males (39.5%) and 26 females (60.5%); their mean age was 65.47 ± 10.15 years. There was a statistically significant difference between studied groups regarding smoking, education, employment, hypertension, hearing impairment, sleep disorders, hypoxia, exposure to pollutants, improper physical and mental activity scores and family history of dementia. Multivariate regression analysis revealed that being divorced, married, low education level and being older significantly independently increased risk of AD and Restless leg syndrome/Insomnia and higher GDS significantly increased the risk of poor QoL of AD patients.There was a statistically significant difference between the studied groups regarding sNFLc (significantly higher in case group), the best cutoff of sNFLC in prediction of AD is ≥ 38.436 with area under curve 0.866, sensitivity 81.4%, specificity 76.7%, positive predictive value 77.8%, negative predictive value 80.5% and overall accuracy 79.1%. At this cutoff risk of AD is 14.4 folds (CI 5–41). Conclusion Serum NFLc shows promise as a blood-based biomarker for predicting Alzheimer’s disease; however, the findings should be interpreted cautiously due to the small sample size. Modifiable risk factors such as diet, sleep disorders, hypoxia, hearing impairment, pollution exposure, hypertension, diabetes, and obesity may contribute to AD risk and progression. Larger studies are required to validate these preliminary results.