Using the Capture-Recapture Method to Estimate the Incidence of Amyotrophic Lateral Sclerosis in Beijing, China

BACKGROUND: To assess the total, gender-related and ageing process-related incidence rates of amyotrophic lateral sclerosis (ALS) in Beijing, China. Determine whether the decreased male to female ratio among postmenopausal age groups. METHODS: We used the 2-source capture-recapture method to estimate the incidence of ALS in Beijing. The primary and secondary data sources were from diagnostic hospitals and assisted care institutions in the same area from 2010 to 2015. RESULTS: A total of 562 cases and 283 cases were extracted from 2 data sources, and a total of 962 patients diagnosed with ALS within the 6-year period were estimated (95% CI 883-1041). The average yearly incidence was 0.77/100,000 persons (95% CI 0.71-0.83). The female to male ratio was 1.63. The incidence was associated with age and peaked in the 55-64 year age group. There was no obvious decline in the male:female ratio among postmenopausal age groups. CONCLUSIONS: The total incidence of ALS in Beijing is similar to international reports. The onset of ALS is not merely the result of ageing.