DENTAL AMALGAM AND MULTIPLE-SCLEROSIS - A CASE-CONTROL STUDY IN MONTREAL, CANADA

Background The aetiology of multiple sclerosis (MS) remains poorly und erstood. Dental amalgams containing mercury have recently been suggest ed as a possible risk factor for MS. Methods In a case-control study c onducted between 1991 and 1994, we interviewed a total of 143 MS patie nts and 128 controls, to obtain information on socio-demographic chara cteristics and the number of dental amalgams and the time since instal lation based on dentists' records. Results Neither the number nor the duration of exposure to amalgams supported an increased risk of MS. Af ter adjustment for age, sex, smoking, and education those who had more than 15 fillings had an odds ratio (OR) of 2.57 (95% CI:0.78-8.54) co mpared to those who had none; for individuals whose first amalgam was inserted more than 15 years prior to the study, we found an OR of 1.34 (95% CI:0.38-4.72). Conclusions Although a suggestive elevated risk w as found for those individuals with a large number of dental amalgams, and for a long period of time, the difference between cases and contr ols was not statistically significant.