Determinants of stroke in women
The effect of a number of possible risk factors for stroke were examined in a nested case-control study of participants in the prospective Royal College of General Practitioners' Oral Contraception Study. The case were 253 women who had a first ever stroke or episode of amaurosis fugax between 1968 and 1990. Three age-matched controls were selected for each case. Current users of the pill had an increased risk of total and fatal stroke. Former users had a small elevated risk of total stroke and a stronger risk of fatal stroke. The effects in former users appeared to be restricted to women who smoked. The elevated risk of total stroke among former users appeared to diminish with time although a persisting risk of fatal or haemorrhagic stroke could not be excluded. Smoking increased the case fatality rates of pill users who had a stroke. The effects of the pill in women with other factors for stroke were explored, but were inconclusive. The newer oral contraceptives were associated with a lower risk of stroke than older preparations, a benefit which has occurred because of changes in pill formulation rather than more selective prescribing by doctors. Smoking enhanced the risk of cerebrovascular disease in hypertensive, and possibly diabetic, women. The largest population attributable proportions were associated with smoking (36%), ever use of oral contraceptives (23%), manual social class (21%) and hypertension (19%). The successful elimination of cigarette smoking must remain a public health priority.