Journal Article

Spatio-temporal clustering of amyotrophic lateral sclerosis in France: A population-based study

Lagrange, Emmeline, Esselin, Florence, De La Cruz, Elisa, Bonneterre, Vincent, Marin, Benoît, Couratier, Philippe, Lautrette, Géraldine, Luna, Jaime, Boumédiene, Farid, Camu, William, Besson, Gérard, Preux, Pierre Marie

2022

Overview

ObjectiveTo assess spatial aggregates of amyotrophic lateral sclerosis (ALS) incident cases, using a solid geo-epidemiological statistical method, in France.MethodsThis population-based study (2003–2011) investigated 47.1 million person-years of follow-up (PYFU). Case ascertainment of incident ALS cases was based on multiple sources (ALS referral centers, hospital centres and health insurance data). Neurologists confirmed all ALS diagnoses. Exhaustiveness was estimated through capture-recapture. Aggregates were investigated in four steps: (a) geographical modelling (standardized incidence ratio (SIR) calculation), (b) analysis of the spatial distribution of incidence (Phothoff-Winttinghill’s test, Global Moran’s Index, Kulldorf’s spatial scan statistic, Local Moran’s Index), (c) classification of the level of certainty of spatial aggregates (i.e. definite cluster; probable over-incidence area; possible over-incidence area) and (d) evaluation of the robustness of the results.ResultsThe standardized incidence of ALS was 2.46/100,000 PYFU (95% CI 2.31–2.63, European population as reference) based on 1199 incident cases. We identified 13 areas of spatial aggregates: one cluster (stable in robustness analysis), five probable over-incidence areas (2 stable in robustness analysis) and seven possible over-incidence areas (including 4 stable areas in robustness analysis). A cluster was identified in the Rhône-Alpes region: 100 observed vs 54.07 expected cases for 2,411,514 PYFU, SIR: 1.85 (95% CI 1.50–2.25).ConclusionWe report here one of the largest investigations of incidence and spatial aggregation of ALS ever performed in a western country. Using a solid methodology framework for case ascertainment and cluster analysis, we identified 13 areas that warrant further investigation.

• Publisher: Springer Nature B.V
• Subject: Aggregates / Amyotrophic lateral sclerosis / Capture-recapture studies / Cluster analysis / Clustering / Epidemiology / Investigations / Population (statistical) / Population studies / Population-based studies / Robustness / Spatial analysis / Spatial distribution / Statistical analysis / Statistical methods