Breast implants and risk of neurologic disease: a population-based cohort study in Sweden.

[OBJECTIVE] To examine the risk of neurologic disorders among women with breast implants.

[BACKGROUND] Case reports in the literature have raised concern about a possible link between silicone breast implants and some types of neurologic disorders, but there is a dearth of epidemiologic studies in this area.

[METHODS] Through the nationwide Swedish hospital discharge register, we identified a population-based cohort of 7433 women with breast implants. A similarly identified cohort of 3351 women who underwent breast reduction surgery served as a comparison. The women were followed from 1972 (or date of breast surgery if it occurred later) through 1993 by means of record linkages and review of inpatient medical records. Ratios of observed to expected numbers, and relative risks (RR) with 95% confidence intervals (CI), were calculated as measures of the risk of neurologic diseases among women with implants.

[RESULTS] A direct comparison of the exposed (implant) versus comparison (breast reduction) groups, after exclusion of patients with pre-existing disease or incorrect neurologic diagnoses, showed no excess risk among implant patients (RR = 0.8; 95% CI = 0.5 to 1.4). When external rates derived from the background population were used as comparison, we found a small, statistically nonsignificant excess of neurologic disorders both in the breast implant (RR = 1.3; 95% CI = 0.9 to 1.9) and the breast reduction (RR = 1.5; 95% CI = 0.9 to 2.4) cohorts.

[CONCLUSION] Our results provide no support for the conjecture that breast implants cause neurologic disease.