Background Apart from increasing age and a few specific genetic polymorphisms, the aetiology of Motor Neurone Disease is largely unknown. Only 5–10% of cases are familial with the vast majority being of the sporadic form. A role for environmental exposures is suggested by the lack of evidence for a genetic component, differences in incidence by geographical region, increases in incidence observed in some countries (including New Zealand) over a relatively short period, associations observed in epidemiological studies, and the higher proportion of males affected. We conducted a New Zealand population-based case-control study to investigate associations between occupational exposures and MND.

Methods We recruited both prevalent and incident cases from a voluntary register, supplemented by notifications from neurologists. General population controls were selected from the Electoral Roll. A standardised questionnaire was used to obtain information on personal and demographic details, lifestyle factors and a full occupational history. We estimated odds ratios by occupation and industry, with analyses adjusted for age, gender, ethnicity, SES and smoking using logistic regression.

Results We interviewed 265 cases and 532 controls. Two thirds of cases were male, with 70% aged over 60. Significantly elevated risks were observed for Telecommunications Technicians OR = 4.2 (95% CI: 1.2–14.0), Forecourt Attendants OR = 6.2 (1.3–30.2), Agriculture and Fishery Workers OR = 1.5 (1.1–2.2), Market Farmers and Crop Growers OR = 1.9 (1.1–3.3), Fruit Grower/Worker OR = 2.7 (1.2–6.3), Building Trades Workers OR = 1.8 (1.1–3.0), Builders Labourers OR = 4.3 (1.1–16.7) and Agricultural, Earthmoving and Other Materials-Handling Equipment Operators OR = 2.6 (1.1–6.1). There was also a non-significant elevation in Electricians (OR = 3.1). Analyses by industry showed significantly elevated risks in agricultural (particularly horticulture and fruit growing), construction, automotive fuel retailing and computer services.

Discussion These preliminary results are consistent with those reported in the literature, and suggest that occupational exposures such as pesticides and ELF-MF may play a role in MND in New Zealand.