Oral Contraceptives · Autoimmune Disease Risk
Hernán MA et al., 2000 · Neurology
Experimental and clinical data suggest a protective effect of estrogens on the development and progression of MS. We assessed whether MS incidence was associated with oral contraceptive use or parity in two cohort studies of U.S. women, the Nurses' Health Study (NHS; 121,700 women aged 30 to 55 years at baseline in 1976) and the Nurses' Health Study II (NHS II; 116,671 women aged 25 to 42 years at baseline in 1989). Participants with a diagnosis of MS before baseline were excluded. Oral contraceptive history and parity were assessed at baseline and updated biennially. During follow-ups of 18 years (NHS) and 8 years (NHS II) we documented a total of 315 definite or probable cases of MS. Neither use of oral contraceptives nor parity were significantly associated with the risk of MS. As compared with women who never used oral contraceptives, the age-adjusted relative risk (95% CI) was 1.2 (0.9, 1.5) for past users, and 1.0 (0.6, 1.7) for current users. Similar results were obtained after adjustment for latitude, ancestry, and other potential confounding factors. There was no clear trend of MS risk with either increasing duration of use or time elapsed since last use. Age at first birth was also not associated with the risk of MS. These prospective results do not support a lasting protective effect of oral contraceptive use or pregnancy on the risk of MS. The decision to use hormonal contraception should not be affected by its effects on the risk of MS.
Oral Contraceptives · Autoimmune Disease Risk
Thorogood M et al., 1999 · Br J Obstet Gynaecol
To examine the risk of multiple sclerosis in users of combined oral contraceptives.
Cohort study conducted between 1968 and 1996 using diagnostic data supplied by general practitioners General practices throughout the United Kingdom. Royal College of General Practitioners' Oral Contraception Study cohort of initially 46,000 women recruited during the late 1960s. Directly standardised incidence rates of multiple sclerosis were calculated for current, former and never-users of oral contraceptives using first ever cases of multiple sclerosis reported by the general practitioners. The standardisation variables were age, parity, social class and smoking history. Five-year survival rates in the different contraceptive groups were calculated using standard life table techniques. One hundred and fourteen first ever cases of multiple sclerosis had been reported by November 1996 during 564,000 woman-years of observation. The incidence rate in both current and former users was not materially different to that in never-users. Although based on limited evidence there was no suggestion that the five-year survival was affected by a woman's use of combined oral contraceptives. These findings do not suggest a greatly elevated risk of multiple sclerosis during, or after, use of combined oral contraceptives.
Oral Contraceptives · Autoimmune Disease Risk
Alonso A et al., 2005 · Arch Neurol
Exogenous estrogens affect the onset and clinical course of experimental allergic encephalomyelitis. Oral contraceptives, a frequent source of exogenous estrogens in humans, could have a role in the development of multiple sclerosis (MS). To examine whether recent oral contraceptive use and pregnancy history are associated with the risk of MS. DESIGN AND A case-control study nested in the General Practice Research Database. This database contains prospective health information (drug prescriptions and clinical diagnoses) on more than 3 million Britons who are enrolled with selected general practitioners. One hundred six female incident cases of MS, younger than 50 years, with at least 3 years of continuous recording in the General Practice Research Database before the date of first symptoms (index date), identified between January 1, 1993, and December 31, 2000, and 1001 controls matched on age, practice, and date of joining the practice. Main Outcome Measure Incidence of first symptoms of MS, confirmed through medical records. The incidence of MS was 40% lower (odds ratio, 0.6; 95% confidence interval, 0.4-1.0) in oral contraceptive users compared with nonusers during the previous 3 years. The risk of MS increased in the 6 months after pregnancy (odds ratio, 2.9, 95% confidence interval, 1.2-6.6), but it was not otherwise related to parity. The hormonal changes that occur during oral contraceptive use and pregnancy may be associated with a short-term reduction in the risk of MS, and the postpartum period may be associated with a short-term increase in the risk of MS.
Oral Contraceptives · Autoimmune Disease Risk
Villard-Mackintosh L et al., 1993 · Contraception
Data from the Oxford.FPA prospective study show that oral contraceptive use and pregnancy have no discernible effect on the risk of developing multiple sclerosis (MS). Women of parity 0-2 developed MS twice as often as women of parity 3 or more but the difference did not reach statistical significance. Smoking may be a risk factor for developing MS. A nested case-control analysis did not identify any associations between MS onset and preceding illnesses.
