The Multistep Process for Amyotrophic Lateral Sclerosis: A Study in the Province of Palermo, Northern Sicily

Abstract

Objective: Recent studies have suggested that the clinical onset of Amyotrophic Lateral Sclerosis (ALS) is the final expression of a multistep process. We evaluated the conformity of the hypothesis in a relatively small yet well-defined ALS population in the Province of Palermo, Sicily Island, almost entirely followed by the local tertiary ALS Clinical Center. Methods: Incident data were extracted from the patients’ database of the ALS Center (years 2014-2020). We examined both sporadic and familial forms of the disease. To evaluate the multistep process in our population, we regressed the natural log of age-specific incidence against the natural log of age of the patients. Results: We identified 175 ALS patients. We obtained a slope of 4.69 (r2 = 0.986); the CI95% stands at 3.86-5.53 values, remaining relatively large due to the small sample share and with a p-value=0.00038. The slope estimate was consistent with a 6-step process. Conclusions. In the ALS population of the Province of Palermo, Sicily, the multistep analysis confirms a process consistent with a 6-step model. This data, obtained in a relatively homogeneous population, further highlights the probability of strict interaction between environmental and genetic variables in the disease. Our data offer insights into the complexity of the mechanisms involved in the pathogenesis of the disease, particularly during its asymptomatic phase. This study supports the hypothesis that a single therapeutic silver bullet would probably be insufficient to arrest or slow the disease’s progression.