Amyotrophic lateral sclerosis mortality rates among ethnic groups in a predominant admixed population in Latin America: a population-based study in Ecuador.

Current evidence suggests heterogeneity of amyotrophic lateral sclerosis (ALS) among geographic areas and populations. Lower mortality rates have been reported in admixed populations compared to European origin populations. We aimed to describe and compare ALS mortality rates among ethnic groups using a population-based approach in a multiethnic country. Annual mortality cause registers were searched to determine ALS deaths from the National Institute of Statistics and Censuses in Ecuador (INEC) from 1990 to 2016. Mid-year population was considered for each year. The time trend was assessed using a negative binomial regression. Rate ratio statistics were performed to compare the age and sex standardized rates based on the 2010 US population among ethnic groups. Overall, 570 ALS deaths were identified. ALS mortality showed an age-related profile with a peak between 55 and 70 years. After age-sex standardization on the 2010 US population, mortality rate was 0.33 (CI 0.30-0.36) per 100,000. The time trend showed an increase of ALS mortality (p < 0.001). There was no statistical difference in age-sex standardized mortality rates per 100,000 when admixed was compared to white (p = 0.231) and black (p = 0.125). Differences reached statistical significance between admixed and other ethnics (p = 0.015). Our population-based study supports the hypothesis that ALS occurrence is lower in predominant admixed populations from Latin America compared to European and Northern American populations. Further studies are needed to clarify the role of ancestral origin in ALS susceptibility.

Ethnic and demographic incidence of amyotrophic lateral sclerosis (ALS) in Brazil: A population based study.

Our objectives were to examine demographic and ethnic factors associated with amyotrophic lateral sclerosis in Brazil. The method used was a retrospective study of death certificates performed in June 2015, identifying the incidence of amyotrophic lateral sclerosis over 10 years, from January 2004 to December 2013, related to gender, age and race. Results revealed 8942 death certificates with 8152 as the underlying cause and 790 as a secondary cause. The average age was 62.7 ± 13.2 years, with a predominance of males (1·3:1). The adjusted mortality rate over 20 years was 0.61 to 0.89/100,000 person-years, and over 45 years was 1.77 to 2.3/100,000 person-years. There was a predominance of amyotrophic lateral sclerosis in Caucasians compared to the general population above 20 years (2010 Census), with an odds ratio (OR) of 2.92 (95% CI 2.78-3.07). The OR in blacks was 0.04 (95% CI: 0.03-0.04), in mestizos was 0.05 (0.04-0.07), and in Indians was 0.02 (0.01-0.04). The mean age was lower than in European populations (48.5 ± 12.3 years) (p < 0.0001). In conclusion, the incidence of amyotrophic lateral sclerosis in Brazil is close to other Latin American populations, with a lower age at death and clear predominance in Caucasians.

Survival and clinical features in Hispanic amyotrophic lateral sclerosis patients.

The demography, survival, and motor phenotypes of amyotrophic lateral sclerosis (ALS) patients have been rarely described in Hispanic countries. The clinical characteristics and survival of a series of Mexican ALS patients are described. Mexican patients with definite ALS were included in a five-year retrospective longitudinal study. Their demographic and clinical features, cumulative survival rates, and independent predictive factors for survival were analysed. Sixty-one definite ALS patients were included. The median follow-up period was 35 months (range 12-108 months). Males were predominant (1.8: 1), the mean age at onset was 47.5 ± 10.5 years, and the median interval from onset to diagnosis was 12 months. Spinal onset occurred in 66% of patients. Upper motor neuron phenotype was predominant in 53% of patients. The overall mean survival from onset was 68.6 months, and from diagnosis was 57.8 months. Longer survival was determined in patients aged ≤ 40 years (54.7 months) compared with other age groups (p = 0.006). In conclusion, the clinical heterogeneity, male predominance, and survival rates in our sample are consistent with those of other studies. Patients in this series had a younger age at onset and a clear trend toward longer survival compared with those of other population studies.

Reduced frequency of ALS in an ethnically mixed population: a population-based mortality study.

OBJECTIVE: To describe ALS mortality rates in the well-characterized ethnically mixed Cuban population over a 6-year period. BACKGROUND: There have been few population-based epidemiologic studies of ALS in non-Europeans. Preliminary data from the United States suggest a lower frequency of ALS in Hispanic and African groups compared with those of European descent. The Cuban population of 11 million comprises three main ancestral groups classified by skin color as white (65%), mixed (24%), and (black 10%). Medical care is of a high standard and is free. Cuba is ideally placed to establish the frequency of ALS in an admixed population of diverse ethnic origin. METHODS: Multiple-cause mortality files from the Central Statistics office in Cuba for the years 2001 through to 2006 were searched for codes corresponding to ALS. Age-adjusted mortality rates were calculated by sex, race/ethnicity, age, and geographic region at time of death. RESULTS: Four hundred thirty-two patients with a diagnosis of ALS were identified. The mean age at death was 63.7 years. There was a slight male predominance (1.1:1). The adjusted death rate from ALS for the total population older than 15 years was 0.83 per 100,000. The adjusted mortality rate per 100,000 was considerably lower in the mixed population (0.55; confidence interval [CI] 0.4-0.72) than in whites (0.93; CI 0.83-1.03) and blacks (0.87; CI 0.62-1.17). There was no correlation between the number of neurologists in each region and the mortality rate from ALS (r = 0.268, p = 0.335). CONCLUSIONS: The overall mortality rate from ALS in Cuba is similar to that described in Hispanic populations in the United States and is lower than in Northern European populations. Mortality from ALS is lowest in a population of mixed ancestry. Ancestral origin is likely to play a role in ALS susceptibility.