The epidemiology of amyotrophic lateral sclerosis in Moscow (Russia)

Objectives: To estimate the incidence of amyotrophic lateral sclerosis (ALS) in Moscow by investigating multiple sources of cases. Incidence rates from previous Russian studies ranged from 0.3 to 0.7 per 100,000/year. Methods: A retrospective study of the incidence of ALS was performed in the South district of Moscow (population, 1,760,000, 2015). Several data sources were investigated. The medical records of the calendar year 2015 were examined by an ALS expert who accepted only patients with definite or probable ALS according to the revised El Escorial criteria. Crude and standardized incidence rates were calculated, the latter adjusted to the Russian and the European population. Results: Twenty-two patients were found, accounting for a crude incidence of 1.25/100,000/year (95% CI 0.78-1.89) and a standardized incidence of 1.22 (Russia) and 1.28 (Europe). The sample included 11 men and 11 women aged 36-73 years (mean 56). Five patients (23%) had bulbar onset ALS. The mean diagnostic delay was 12.8 ± 9.2 months (8.5 ± 4.8 in men and 17.2 ± 10.6 in women) (p = 0.02). Family history of ALS was present in two cases. Conclusion: The incidence of ALS in the Russian Federation is higher than previously reported but lower than in other countries. Poor diagnostic ascertainment, particularly in women, and the shorter life expectancy of the Russian population are possible explanations.