Certain Medical Conditions May Signal Early Alzheimer's Years Before Diagnosis, Study Finds

Certain medical conditions, including depression, vertigo, and headaches, may indicate a risk for early-onset Alzheimer's disease several years before a formal diagnosis, according to a new Finnish study.

The research, published in the journal Alzheimer’s & Dementia, analyzed the medical records of 407 individuals diagnosed with early-onset Alzheimer's disease and 4,035 individuals of similar age and sex who did not have the diagnosis. The study focused on the 15 years preceding diagnosis.

Early-onset Alzheimer's is diagnosed in individuals under the age of 65. The average age of diagnosis in the study group was 60.

Researchers found that the following conditions were significantly more prevalent in individuals who were eventually diagnosed with early-onset Alzheimer's:

• Vertigo (5.9% of those with diagnosis, compared to 2.1% without)
• Depression (5.7% vs. 2.3%)
• Headache (4.9% vs. 1.6%)
• Stroke (4.4% vs. 2.0%)
• Alcohol-related disorders (3.4% vs. 1.4%)
• Brain disorders (2.9% vs. 0.9%)
• Thyroid disorders (2.5% vs. 0.8%)
• Epilepsy (2.2% vs. 0.7%)
• Delirium (1.5% vs. 0.1%)
• Ear, nose, and throat disorders (5.2% vs. 2.9%)

The differences in the prevalence of these conditions were most pronounced in the five years leading up to an early-onset Alzheimer's diagnosis. The study also noted a substantial increase in healthcare visits among early-onset Alzheimer's patients immediately before and during the period of diagnosis, suggesting the emergence of symptoms.

"It is well-known that the neuropathological changes associated with Alzheimer’s disease begin at least 15 to 20 years before clinical cognitive symptoms appear," said Dr. Suvi-Johanna Krüger, a study co-author and clinical lecturer at the University of Oulu. "Most previous studies have focused on late-onset Alzheimer’s disease, and considerably less is known about early-onset Alzheimer’s disease."

The study acknowledges limitations, noting that as an observational study, it can only establish associations and cannot prove that these conditions reliably predict Alzheimer's disease. "Our study cannot determine whether these conditions cause early-onset Alzheimer’s disease or whether they are consequences of the underlying disease process," Krüger stated. Some conditions might be risk factors, while others could be early symptoms or changes occurring during the disease's prodromal phase.

Factors such as genetics, lifestyle, and socioeconomic status may also have played a role in patient outcomes. The researchers were unable to independently verify all medical diagnoses or assess disease severity. Furthermore, the findings may not be generalizable to populations outside of Finland.

Larger studies incorporating disease biomarkers, genetics, and clinical assessments are needed to determine if a causal relationship exists between these medical conditions and Alzheimer's incidence, and if these patterns could aid in early detection. Experts emphasize the importance of consulting a healthcare provider for any persistent medical symptoms, including memory or cognitive issues, as early diagnosis allows for more available treatment and support options, as well as time for future planning.