Conference Coverage
BALTIMORE—The age of disease onset in patients with amyotrophic lateral sclerosis (ALS) is significantly earlier in non-Caucasians than in Caucasians, according to research presented at the 139th Annual Meeting of the American Neurological Association. In non-Caucasians, the mean age at onset of ALS is 55.6, compared with a mean age of 61.4 among Caucasians.
It is unclear whether the earlier age of disease onset results from a biological phenomenon or is a consequence of socioeconomic factors, commented Hristelina Ilieva, MD, PhD. “Comparison of comorbidities, neurologic and nonneurologic, may help us further understand this finding,” she added. Dr. Ilieva is a neurology resident at the Methodist Neurological Institute in Houston.
Studies have found increasing evidence of ethnic variation in the incidence of motor neuron diseases. For example, Asians have the lowest reported incidence, while the incidence is intermediate in African populations, mixed in Central and South American populations, and highest in Caucasians. Prior research has also found significant differences between Caucasians and African Americans in the age of disease onset and in disease course.
Dr. Ilieva and Ericka Simpson, MD, Director, Neurology Residency Program and Neuromuscular Medicine Fellowship Program at the Methodist Neurological Institute, conducted a retrospective review based on a database of all patients who were evaluated and diagnosed with definite or probable ALS. The patients were grouped into two categories—373 Caucasians and 86 non-Caucasians, which included Asians, Hispanics, and African Americans.
The researchers compared the age of disease onset, time to diagnosis, initial BMI, site of disease onset, disease progression, and early disease course between the two groups of participants. In addition, the investigators compared ALS Functional Rating Scale–Revised scores for the subgroup of patients who had three consecutive visits. Disease progression was measured using the Appel ALS score. Statistical analyses were performed using two-tailed t-test.
Among non-Caucasians, the mean age of disease onset was 55.4 in males and 55.7 in females. In Caucasians, the mean age of disease onset was 60.2 in males and 62.9 in females. Overall, the time to diagnosis in non-Caucasians was 19.6 months, compared with 16.3 months in Caucasians.
“We confirmed prior observations that non-Caucasian patients’ age of disease onset is significantly earlier than in Caucasian patients,” said Dr. Ilieva. “This observation was consistent between genders as well. Unlike earlier reports, we were unable to find a difference in disease course between the two groups. Our results may be affected by the dropout of patients seen in follow-up.”
Previous studies had also found that non-Caucasians may present with more advanced disease at their initial visit. “We calculated preslope and delta factor of safety to address this possibility and were unable to confirm this observation in our cohort,” Dr. Ilieva commented.
—Colby Stong