Neurologic disease among women with breast implants.

Objective: To investigate the risk of neurologic disease among women with silicone breast implants.
Background: Since 1992, several case series reported an association between silicone breast implants and neurologic diseases.
Methods: Between 1977 and 1992, 1,135 women received cosmetic silicone breast implants, and 7,071 women had breast reduction surgery, as identified by the Danish National Register of Patients (NRP). NRP files provided information on numbers and types of subsequent neurologic disorders at hospital discharge, which were compared with expected numbers, calculated on the basis of national hospital discharge rates.
Results: In the two study cohorts, hospital discharge rates for neurologic diseases were raised by some 60% to 70% compared with Danish women in general. Among women with silicone breast implants, 13 subsequently developed a neurologic disorder compared with 7.7 expected; whereas in the comparison group, 63 observed versus 39.1 expected disorders were recorded. These results indicate that relative to the comparison cohort, women with implants had no excessive levels of definite neurologic disease. Furthermore, medical record reviews revealed that the majority of women with implants discharged with a neurologic diagnosis had either symptoms before implant surgery or neurologic symptoms secondary to degenerative diseases.
Conclusions: Our findings do not support the hypothesis of silicone-induced neurologic disease. The reasons for the elevated rates of neurologic disease in both the exposed and comparison cohorts remain unclear, but may reflect selection processes associated with these women seeking medical care more often than the general population.