Haemorrhagic stroke, overall stroke risk, and combined oral contraceptives: Results of an international, multicentre, case-control study

Haemorrhagic stroke, overall stroke risk, and combined oral contraceptives: Results of an international, multicentre, case-control study

Author Poulter, N. R. Google Scholar
Chang, C. L. Google Scholar
Farley, TMM Google Scholar
Meirik, O. Google Scholar
Marmot, Michael Gideon Google Scholar
Debert-Ribeiro, Myriam Autor UNIFESP Google Scholar
Institution WHO
Universidade Federal de São Paulo (UNIFESP)
UNIV CHILE
ESCUELA MED
NATL RES INST FAMILY PLANNING
SICHUAN FAMILY PLANNING RES INST
SHANGHAI INST PLANNED PARENTHOOD RES
UNIV VALLE
UNIV OXFORD
ZENTRUM EPIDEMIOL & GESUNDHEITSFORSCH
CHINESE UNIV HONG KONG
ALBERT SZENT GYORGYI MED UNIV
UNIV INDONESIA
UNIV W INDIES
KENYA GOVT MED RES CTR
GRP INTERUNIV MEXICANO INVEST EPIDEMIOL SALUD REP
UNIV LJUBLJANA
CHULALONGKORN HOSP
SIRIRAJ HOSP
UNIV BELGRADE
UNIV LUSAKA
UNIV ZIMBABWE
KAISER PERMANENTE
NIH
UNIV AARHUS
UNIV LONDON LONDON SCH HYG & TROP MED
Abstract Background The risk of haemorrhagic stroke associated with use of oral contraceptives (OCs) is less well-established than that for ischaemic stroke. We assessed the risk of haemorrhagic stroke associated with current use of modern OCs as now used throughout the world.Methods In this WHO collaborative, case-control study, we assessed the association between risk of haemorrhagic stroke and use of combined OCs in 1068 cases, 20-44 years, and 2910 age-matched controls. We also assessed risks for all strokes combined (haemorrhagic, ischaemic, and unclassified) based on 2198 cases and 6086 controls.Findings Overall, current use of combined OCs was associated with slightly increased risk of haemorrhagic stroke; the increase was significant in the developing countries (odds ratio 1 . 76 [95% CI 1 . 34-2 . 30]) but not in Europe (1 . 38 [0 . 84-2 . 25]). Use of OCs in women younger than 35 years did not affect risk of haemorrhagic stroke in either group of countries, whereas in women aged older than 35 years, odds ratios were greater than 2. Women who were current users of OCs and had a history of hypertension (detected before current episode of OC use, but not during pregnancy) had a substantially increased risk (ten-fold to 15-fold) of haemorrhagic stroke compared with women who did not use OCs and had no history of hypertension. Odds ratios among current OC users who were also current cigarette smokers were greater than 3. In both groups of countries, past use of OCs, dose of oestrogen, and dose and type of progestagen had no effect on risk, and risks were similar for subarachnoid and intracerebral haemorrhage.The odds ratios for any type of stroke associated with current use of low-dose (<50 mu g oestrogen) and higher-dose OCs were 1 . 41 (0 . 90-2 . 20) and 2 . 71 (1 . 70-4 . 32), respectively, in Europe and 1 . 86 (1 . 49-2 . 33) and 1 . 92 (1 . 48-2 . 50) in the developing countries. From these data we estimated that about 13% and 8% of all strokes in women aged 20-44 in Europe and the developing countries, respectively, are attributable to the use of OCs.Interpretation The risk of haemorrhagic stroke attributable to OC use is not increased in younger women and is only slightly increased in older women. The estimated excess risk of all stroke types associated with use of low-oestrogen and higher-oestrogen dose OCs in Europe was about two and eight, respectively, per 100 000 woman-years of OC use. However, findings need to be considered in the context of other risks and benefits associated with OC use, as well as those associated with the use of other forms of contraception.
Language English
Date 1996-08-24
Published in Lancet. New York: Elsevier Science Inc, v. 348, n. 9026, p. 505-510, 1996.
ISSN 0140-6736 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 505-510
Origin http://dx.doi.org/10.1016/S0140-6736(95)12394-6
Access rights Closed access
Type Article
Web of Science ID WOS:A1996VD42700010
URI http://repositorio.unifesp.br/11600/44830

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