Intrauterine Devices May be Associated with a Later MS Disease Onset
Objectives: To investigate whether contraceptives influence the age at MS symptom onset.
Methods: Our sample is comprised of a sub-group of 235 women with MS registered with the New York State MS Consortium (NYSMSC) who completed an extensive questionnaire about reproductive events. Women were asked about the type and timing of contraceptives they have used. Statistical analyses used included independent-samples t-tests and linear regression analyses.
Results: There were no MS age at onset differences between those who used oral contraceptive pills (n=195) compared to those who did not. However, women who have used an intrauterine device (IUD) (n=35) had a significantly higher mean age at MS onset of 34.3±10.5, than women who never used an IUD (30.7±8.9, p=0.033). Furthermore, an earlier age when starting the IUD was significantly associated with a later age at MS onset (β=-0.615, p=0.022), even after adjusting for a past pregnancy. Those who started with the IUD earlier (≤ median of 23 years) had a mean age at symptom onset of 38.9±9.7, while those who started later (> median of 23 years) had a mean age at symptom onset of 27.4±8.5, p=0.001.
Conclusions: These preliminary results indicate that use of an IUD may delay the onset of MS symptoms. Information on type of IUD (copper/hormonal) was not available. However, most women in our sample started using an IUD before 1990, suggesting the majority of IUDs would most likely have been copper, non-hormonal based. Copper IUDs have been shown to reduce ferritin levels, thereby possibly influencing underlying pathways of MS disease development.