Trends in motor neuron disease: association with latitude and air lead levels in Spain.
Motor neuron diseases (MND) are a group of disorders characterized by motor neuron degeneration. Among them, amyotrophic lateral sclerosis (ALS) is by far the most common in adulthood. This paper assesses the trend and geographical pattern in MND incidence in Spain and the possible air lead levels effect on this pathology. To confirm this concept, we performed a retrospective analysis of the deaths due to MND in Spain during 2000 and 2013, determined the geographical differences, and explored the relationship between MND and the air levels of lead. Overall, between 2000 and 2013, 11,355 people died in Spain because of MND. Disease mortality significantly increased in recent years (2007-2013) when compared with the first time of the period. Spearman's rank correlation coefficient also showed a statistically significant positive trend (CC = 0.824, p = 0.0002). Among people over 65 years, mortality rates were higher in Northern provinces. Moreover, we found a significant association of MND mortality with higher air lead levels (CC = 0.457, p = 0.01). Our study confirms that MND mortality is increasing in Spain, with a significant latitude gradient, which suggests an important role of environmental exposures. This ecological study suggests that air lead levels may be implicated in ALS pathogenesis.
Unit of Legal Medicine, Department of Physiology and Pharmacology, University of Cantabria, Av Cardenal Herrera Oria s/n, 39011, Santander, Spain. ana.santurtun@unican.es.
Ana
A
Santurtún
Ticnor SL, Santander, Spain.
Alejandro
A
Villar
Neurodegenerative diseases area, Biodonostia Health Research Institute, San Sebastian, Spain.
Manuel
M
Delgado-Alvarado
Service of Neurology, University Hospital Marqués de Valdecilla-IDIVAL (CIBERNED), Santander, Spain.
Javier
J
Riancho
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D004781:Environmental Exposure; D005260:Female; D005843:Geography; D006801:Humans; D015994:Incidence; D007854:Lead; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000453:epidemiology* / Q000209:etiology* / Q000401:mortality; D012189:Retrospective Studies; D013030:Spain / Q000453:epidemiology; D018709:Statistics, Nonparametric
D007854:Lead
ALS; Lead; Motor neuron disease