BY SARAH OWENS
Both before and after diagnosis, patients with amyotrophic lateral sclerosis (ALS) appear to have an increased risk of other neurodegenerative and psychiatric diseases, according to a study published online on July 12 in Neurology.
Moreover, the study found that family members of patients with ALS also had increased risks, as well, although associations were not equivalent among all types of family members. Compared to relatives of the controls, all first-degree relatives of patients with ALS had an increased risk of neurodegenerative diseases, but only children of patients with ALS had a higher risk of psychiatric disorders.
"Familial aggregation of ALS and other neurodegenerative diseases implies a shared etiopathogenesis among all neurodegenerative diseases," the study authors, led by Elisa Longinetti, MSc, of the Department of Medical Epidemiology and Biostatistics at the Karolinska Institute in Solna, Sweden, wrote.
They attributed the hgher risk of psychiatric disorders among patients with ALS and their children "to nonmotor symptoms of ALS and severe stress response toward the diagnosis."
For their study, researchers at the Karolinska Institute analyzed data on all patients in Sweden diagnosed with ALS in the Swedish Multi-Generation Register between 1990 and 2013. They identified 3,648 patients with ALS and matched them by age, sex, and country of birth with 36,480 controls. Then they conducted a series of nested case-control studies to examine the link between ALS, neurodegenerative diseases, and psychiatric disorders.
They found that individuals who'd previously been diagnosed with a neurodegenerative or psychiatric disease had a 49 percent increased risk of ALS (odds ratio 1.49, 95% confidence interval 1.35–1.66) compared to healthy controls. Additionally, patients who'd been diagnosed with ALS had increased risks of other neurodegenerative or psychiatric diseases (hazard ratio 2.90, 95% confidence interval 2.46–3.43) compared to individuals without ALS. The strongest associations were found for dementia (frontotemporal dementia, Alzheimer's disease, and other dementia), Parkinson's disease among neurodegenerative diseases, and for depression, stress-related disorders, and drug abuse/dependence among psychiatric disorders.
The researchers noted several limitations to their study. Among them, they lacked information on the genetic and clinical characteristics of patients with ALS, which prevented separate analyses according to ALS subtypes; misdiagnoses (such as frontotemporal dementia for other dementia) may have occurred; and, because all children analyzed were younger than 60, further analysis is needed to determine neurodegenerative disease risk among this subgroup of relatives.
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Longinetti E, Mariosa D, Larsson H, et al. Neurodegenerative and psychiatric diseases among families with amyotrophic lateral sclerosis. Neurology 2017; Epub 2017 Jul 14.
