UK study underlines safety of contraceptive pill for non-smokers

Latest findings from a UK study established 35 years ago to assess the health outcomes for women using the contraceptive pill during the 1970s and 1980s are published in this week's issue of THE LANCET. The key finding from the study highlights no increased risk of death from any cause (except cervical cancer) for non-smoking pill users; however among heavy smokers the study findings suggest a moderate increase in the risk of death from ischaemic heart disease in women who used the contraceptive pill compared with non-smoking pill users.

As part of the Oxford Family Planning Association study, Martin Vessey from the Institute of Health Sciences, Oxford, UK, and colleagues examined deaths associated with oral contraceptive use and cigarette smoking--issues of public health importance as both use of such contraceptives and smoking are common in women of childbearing age.

Around 17,000 women who were aged 25–39 years between 1968 and 1974 and who used oral contraceptives, a contraceptive diaphragm, or an intrauterine device took part in the study. Follow-up data were available up to the end of 2000 by which time 889 women had died. As expected, an increase in death from cervical cancer among women who had ever used the oral contraceptive pill was more than counterbalanced by a reduction in risk of death from other uterine cancers and ovarian cancer.

There was no overall increased risk of death from all causes considered together among women who used oral contraceptives (regardless of duration of pill use) compared with women in the study who had never used oral contraceptives; the data suggest that the overall risk of death might be lower among oral contraceptive users than among non-users.

In comparison with non-smokers, there was an increase in death from all causes of around 25% for light smokers and more than a doubling of death risk from all causes for heavy smokers (women who smoked more than 15 cigarettes a day).

Martin Vessey comments: "The oral contraceptives widely used in the 1970s and early 1980s have now been shown to have no adverse effect on overall mortality in three major cohort studies including many deaths and large numbers of women with long-term oral contraceptive use. This is a reassuring finding for many older women today. Although the results should not be extrapolated directly to contemporary low-dose pills, they do nonetheless offer considerable encouragement. The effects of cigarette smoking, especially heavy smoking, have again been shown to be very harmful, more than doubling mortality from all causes even in young women in the Oxford FPA study."

Contact: Emeritus Professor Martin P Vessey, Division of Public Health & Primary Health, Care, Institute of Health Sciences, Old Road, Headington, Oxford OX3 7LF, UK;
T) 44-186-522-6994 (secretary);
F) 44-186-522-6993;
E) martin.vessey@dphpc.ox.ac.uk

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