View article

Objective To examine the risk of multiple sclerosis in users of combined oral contraceptives.

Design Cohort study conducted between 1968 and 1996 using diagnostic data supplied by general practitioners

Setting General practices throughout the United Kingdom.

Population Royal College of General Practitioners' Oral Contraception Study cohort of initially 46,000 women recruited during the late 1960s.

Methods 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.

Results One hundred and fourteen first ever cases of multiple sclerosis had been …