RT Journal Article SR Electronic T1 Multiple sclerosis and occupational exposure to chemicals: a co-twin control study of a nationwide series of twins. JF British Journal of Industrial Medicine JO Br J Ind Med FD BMJ Publishing Group Ltd SP 417 OP 419 DO 10.1136/oem.46.6.417 VO 46 IS 6 A1 Juntunen, J A1 Kinnunen, E A1 Antti-Poika, M A1 Koskenvuo, M YR 1989 UL http://oem.bmj.com/content/46/6/417.abstract AB From the Finnish Twin Cohort (n = 27,100 pairs with known zygosity) all cases of diagnosed multiple sclerosis (MS) were reviewed and those with clinically verified MS were invited for further examinations at the Institute of Occupational Health, Helsinki, with their co-twins. Twenty one cases (19 pairs, of which 17 were discordant) fulfilled the strict criteria of MS. Detailed occupational history showed exposure to a mixture of solvents in six subjects, to lead in one, and to trichloroethylene in one. Of these seven, two monozygotic twins had MS whereas the other five cases were healthy co-twins. These results do not support a causal association between occupational exposure to chemicals and the aetiopathogenesis of MS.