In a previous editorial in this journal1 we have argued that there are likely to be important occupational causes of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) (also commonly known as motor neuron disease) which have not yet been discovered or established.

However, for most neurodegenerative diseases, including ALS, the epidemiology has not been ‘done’, and there have been relatively few high-quality studies, in contrast to the situation with other non-communicable diseases (NCDs) such as cancer and respiratory disease.

Nevertheless, a number of occupational exposures are suspected of contributing to the risk of ALS,2 including agricultural chemicals, metals, welding fume, electric shocks and extremely low-frequency electromagnetic fields (ELF-EMFs)3 and organic solvents (eg, formaldehyde), although the evidence to date is inconsistent. Recently, a cluster of motor neurone disease (MND) cases has been linked to exposure to the fumigant methyl bromide.4 Other putative risk factors include military service,5 rural or urban residence, and a history of head injury including sporting injuries.6 ,7

The paper by Peters …