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Philip C Hannaford - One of the best experts on this subject based on the ideXlab platform.
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mortality among contraceptive pill users cohort evidence from royal college of general practitioners Oral Contraception study
BMJ, 2010Co-Authors: Philip C Hannaford, Alison M Elliott, Lisa Iversen, Valerie Christine Angus, Tatiana V Macfarlane, Amanda J LeeAbstract:Objective To see if the mortality risk among women who have used Oral contraceptives differs from that of never users. Design Prospective cohort study started in 1968 with mortality data supplied by participating general practitioners, National Health Service central registries, or both. Setting 1400 general practices throughout the United Kingdom. Participants 46 112 women observed for up to 39 years, resulting in 378 006 woman years of observation among never users of Oral Contraception and 819 175 among ever users. Main outcome measures Directly standardised adjusted relative risks between never and ever users for all cause and cause specific mortality. Results 1747 deaths occurred in never users of Oral Contraception and 2864 in ever users. Compared with never users, ever users of Oral Contraception had a significantly lower rate of death from any cause (adjusted relative risk 0.88, 95% confidence interval 0.82 to 0.93). They also had significantly lower rates of death from all cancers; large bowel/rectum, uterine body, and ovarian cancer; main gynaecological cancers combined; all circulatory disease; ischaemic heart disease; and all other diseases. They had higher rates of violent deaths. No association between overall mortality and duration of Oral contraceptive use was observed, although some disease specific relations were apparent. An increased relative risk of death from any cause between ever users and never users was observed in women aged under 45 years who had stopped using Oral contraceptives 5-9 years previously but not in those with more distant use. The estimated absolute reduction in all cause mortality among ever users of Oral Contraception was 52 per 100 000 woman years. Conclusion Oral Contraception was not associated with an increased long term risk of death in this large UK cohort; indeed, a net benefit was apparent. The balance of risks and benefits, however, may vary globally, depending on patterns of Oral Contraception usage and background risk of disease.
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RCGP'S Oral Contraception STUDY. Authors' reply
BMJ, 2008Co-Authors: Philip C Hannaford, Alison M Elliott, Lisa Iversen, Amanda J Lee, Sivasubramaniam Selvaraj, Valerie Christine AngusAbstract:We presented all relevant results so that readers could decide for themselves whether their interpretation of our findings fits with ours. Brind thinks that the analysis in which both ever and never users lost to follow-up before the age of 38 were excluded (adjusted relative risk 0.95, 95% confidence interval 0.88 to 1.02) shows serious bias and invalidates the main dataset results in which only never users younger than 38 were excluded (0.88, 0.83 to 0.94). Since the total population in each analysis is different, their results should not be compared directly (in the same way that the results from the main and the general practitioner observation dataset should not be compared directly, as indicated in the footnote to table 2). Furthermore, the different standard populations inevitably result in some variation in the point estimates from each analysis. The point estimate of 0.95 from the “fully excluded” analysis is not materially different from that of 0.88 from the “partially excluded” analysis, although the latter is based on more data. In addition, the upper 95% confidence interval of the fully excluded point estimate was just above unity, suggesting no increased risk of overall cancer. The subgroup analyses of duration and time since last use of Oral Contraception included a large number of comparisons, some of which may have reached significance by chance. Although the relative risk of breast cancer was raised among ever users who had stopped 15-20 years previously, it was decreased in those who had stopped more than 20 years previously (0.54, 0.35 to 0.82) and the trend over time was not significant. We cannot explain the increased risk of central nervous system/pituitary cancer among ever users, although the number of women affected was small (49 of the 3877 cancers in the main dataset). We highlighted and discussed the increased risk of any cancer among women using Oral Contraception for more than eight years in the paper, press releases, and media interviews. Our interpretation remains that Oral Contraception was not associated with an overall increased risk of cancer—indeed it may even produce a net public health gain.
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cancer risk among users of Oral contraceptives cohort data from the royal college of general practitioner s Oral Contraception study
BMJ, 2007Co-Authors: Philip C Hannaford, Alison M Elliott, Lisa Iversen, Sivasubramaniam Selvaraj, Valerie Christine Angus, Amanda J LeeAbstract:Objective To examine the absolute risks or benefits on cancer associated with Oral Contraception, using incident data. Design Inception cohort study. Setting Royal College of General Practitioners9 Oral Contraception study. Participants Directly standardised data from the Royal College of General Practitioners9 Oral Contraception study. Main outcome measures Adjusted relative risks between never and ever users of Oral contraceptives for different types of cancer, main gynaecological cancers combined, and any cancer. Standardisation variables were age, smoking, parity, social class, and (for the general practitioner observation dataset) hormone replacement therapy. Subgroup analyses examined whether the relative risks changed with user characteristics, duration of Oral Contraception usage, and time since last use of Oral Contraception. Results The main dataset contained about 339 000 woman years of observation for never users and 744 000 woman years for ever users. Compared with never users ever users had statistically significant lower rates of cancers of the large bowel or rectum, uterine body, and ovaries, tumours of unknown site, and other malignancies; main gynaecological cancers combined; and any cancer. The relative risk for any cancer in the smaller general practitioner observation dataset was not significantly reduced. Statistically significant trends of increasing risk of cervical and central nervous system or pituitary cancer, and decreasing risk of uterine body and ovarian malignancies, were seen with increasing duration of Oral contraceptive use. Reduced relative risk estimates were observed for ovarian and uterine body cancer many years after stopping Oral Contraception, although some were not statistically significant. The estimated absolute rate reduction of any cancer among ever users was 45 or 10 per 100 000 woman years, depending on whether the main or general practitioner observation dataset was used. Conclusion In this UK cohort, Oral Contraception was not associated with an overall increased risk of cancer; indeed it may even produce a net public health gain. The balance of cancer risks and benefits, however, may vary internationally, depending on patterns of Oral Contraception usage and the incidence of different cancers.
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Oral Contraception and eye disease: findings in two large cohort studies
The British journal of ophthalmology, 1998Co-Authors: Martin Vessey, Rosemary Painter, Philip C Hannaford, Jonathan Mant, P Frith, D ChappelAbstract:Aim—To investigate the relation between Oral contraceptive use and certain eye diseases. Methods—Abstraction of the relevant data from the two large British cohort studies of the eVects of Oral Contraception, the Royal College of General Practitioners’ (RCGP) Oral Contraception Study and the Oxford-Family Planning Association (Oxford-FPA) Contraceptive Study. Both cohort studies commenced in 1968 and were organised on a national basis. Between them they have accumulated over 850 000 person years of observation involving 63 000 women. Results—The conditions considered in the analysis were conjunctivitis, keratitis, iritis, lacrimal disease, strabismus, cataract, glaucoma, retinal detachment, and retinal vascular lesions. With the exception of retinal vascular lesions, there was no consistent evidence of important increases in risk of eye diseases in users of Oral Contraception. There was about a twofold increase in the risk of retinal vascular lesions in recent pill users in both studies (statistically significant only in the RCGP study). The increase was not limited to any specific type of lesion and may well reflect diagnostic bias. Conclusion—Oral contraceptive use does not appear to increase the risk of eye disease, with the possible exception of retinal vascular lesions.
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Oral Contraception and stroke. Evidence from the Royal College of General Practitioners' Oral Contraception Study.
Stroke, 1994Co-Authors: Philip C Hannaford, Peter Croft, C R KayAbstract:A nested case-control analysis of data collected during the prospective Royal College of General Practitioners' Oral Contraception Study was performed to examine the relation between use of Oral Contraception and risk of stroke.The 253 women who had a first-ever stroke (International Classification of Diseases, eighth revision, codes 4300 to 4389) or amaurosis fugax (code 3791) between 1968 and 1990 (case subjects) were compared with 759 women who did not have this diagnosis (control subjects).Smoking, social class, and history of hypertension were found to be important risk factors for stroke. Women who had ever used Oral contraceptives had an increased risk of all stroke (odds ratio, 1.5; 95% confidence interval, 1.1 to 2.0, adjusted for smoking and social class) and of a fatal event (adjusted odds ratio, 2.3; 95% confidence interval, 1.2 to 4.4). A significant doubling of all stroke risk was observed among current users, an effect that was apparent in both smokers and nonsmokers. Former users had a sma...
Rosemary Painter - One of the best experts on this subject based on the ideXlab platform.
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Oral Contraception and ear disease: findings in a large cohort study.
Contraception, 2001Co-Authors: Martin Vessey, Rosemary PainterAbstract:A number of authors have suggested that Oral contraceptives may increase the risk of certain ear diseases, especially otosclerosis and vestibular disorders, although the amount of published information on this topic is limited. We have analyzed the available data on ear disease in the Oxford-Family Planning Association contraceptive study that includes 17,032 women followed for periods of up to 26 years. No evidence of any adverse effect of Oral contraceptives on ear disease was detected. A protective effect of Oral contraceptives against wax in the ear has been described in the Royal College of General Practitioners Oral Contraception study. The amount of data available in the Oxford-Family Planning Association study was too small to permit confirmation or refutation of this finding.
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Oral Contraception and eye disease: findings in two large cohort studies
The British journal of ophthalmology, 1998Co-Authors: Martin Vessey, Rosemary Painter, Philip C Hannaford, Jonathan Mant, P Frith, D ChappelAbstract:Aim—To investigate the relation between Oral contraceptive use and certain eye diseases. Methods—Abstraction of the relevant data from the two large British cohort studies of the eVects of Oral Contraception, the Royal College of General Practitioners’ (RCGP) Oral Contraception Study and the Oxford-Family Planning Association (Oxford-FPA) Contraceptive Study. Both cohort studies commenced in 1968 and were organised on a national basis. Between them they have accumulated over 850 000 person years of observation involving 63 000 women. Results—The conditions considered in the analysis were conjunctivitis, keratitis, iritis, lacrimal disease, strabismus, cataract, glaucoma, retinal detachment, and retinal vascular lesions. With the exception of retinal vascular lesions, there was no consistent evidence of important increases in risk of eye diseases in users of Oral Contraception. There was about a twofold increase in the risk of retinal vascular lesions in recent pill users in both studies (statistically significant only in the RCGP study). The increase was not limited to any specific type of lesion and may well reflect diagnostic bias. Conclusion—Oral contraceptive use does not appear to increase the risk of eye disease, with the possible exception of retinal vascular lesions.
Martin Vessey - One of the best experts on this subject based on the ideXlab platform.
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Oral Contraception and ear disease: findings in a large cohort study.
Contraception, 2001Co-Authors: Martin Vessey, Rosemary PainterAbstract:A number of authors have suggested that Oral contraceptives may increase the risk of certain ear diseases, especially otosclerosis and vestibular disorders, although the amount of published information on this topic is limited. We have analyzed the available data on ear disease in the Oxford-Family Planning Association contraceptive study that includes 17,032 women followed for periods of up to 26 years. No evidence of any adverse effect of Oral contraceptives on ear disease was detected. A protective effect of Oral contraceptives against wax in the ear has been described in the Royal College of General Practitioners Oral Contraception study. The amount of data available in the Oxford-Family Planning Association study was too small to permit confirmation or refutation of this finding.
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Oral Contraception and eye disease: findings in two large cohort studies
The British journal of ophthalmology, 1998Co-Authors: Martin Vessey, Rosemary Painter, Philip C Hannaford, Jonathan Mant, P Frith, D ChappelAbstract:Aim—To investigate the relation between Oral contraceptive use and certain eye diseases. Methods—Abstraction of the relevant data from the two large British cohort studies of the eVects of Oral Contraception, the Royal College of General Practitioners’ (RCGP) Oral Contraception Study and the Oxford-Family Planning Association (Oxford-FPA) Contraceptive Study. Both cohort studies commenced in 1968 and were organised on a national basis. Between them they have accumulated over 850 000 person years of observation involving 63 000 women. Results—The conditions considered in the analysis were conjunctivitis, keratitis, iritis, lacrimal disease, strabismus, cataract, glaucoma, retinal detachment, and retinal vascular lesions. With the exception of retinal vascular lesions, there was no consistent evidence of important increases in risk of eye diseases in users of Oral Contraception. There was about a twofold increase in the risk of retinal vascular lesions in recent pill users in both studies (statistically significant only in the RCGP study). The increase was not limited to any specific type of lesion and may well reflect diagnostic bias. Conclusion—Oral contraceptive use does not appear to increase the risk of eye disease, with the possible exception of retinal vascular lesions.
C R Kay - One of the best experts on this subject based on the ideXlab platform.
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Oral Contraception and stroke. Evidence from the Royal College of General Practitioners' Oral Contraception Study.
Stroke, 1994Co-Authors: Philip C Hannaford, Peter Croft, C R KayAbstract:A nested case-control analysis of data collected during the prospective Royal College of General Practitioners' Oral Contraception Study was performed to examine the relation between use of Oral Contraception and risk of stroke.The 253 women who had a first-ever stroke (International Classification of Diseases, eighth revision, codes 4300 to 4389) or amaurosis fugax (code 3791) between 1968 and 1990 (case subjects) were compared with 759 women who did not have this diagnosis (control subjects).Smoking, social class, and history of hypertension were found to be important risk factors for stroke. Women who had ever used Oral contraceptives had an increased risk of all stroke (odds ratio, 1.5; 95% confidence interval, 1.1 to 2.0, adjusted for smoking and social class) and of a fatal event (adjusted odds ratio, 2.3; 95% confidence interval, 1.2 to 4.4). A significant doubling of all stroke risk was observed among current users, an effect that was apparent in both smokers and nonsmokers. Former users had a sma...
D Chappel - One of the best experts on this subject based on the ideXlab platform.
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Oral Contraception and eye disease: findings in two large cohort studies
The British journal of ophthalmology, 1998Co-Authors: Martin Vessey, Rosemary Painter, Philip C Hannaford, Jonathan Mant, P Frith, D ChappelAbstract:Aim—To investigate the relation between Oral contraceptive use and certain eye diseases. Methods—Abstraction of the relevant data from the two large British cohort studies of the eVects of Oral Contraception, the Royal College of General Practitioners’ (RCGP) Oral Contraception Study and the Oxford-Family Planning Association (Oxford-FPA) Contraceptive Study. Both cohort studies commenced in 1968 and were organised on a national basis. Between them they have accumulated over 850 000 person years of observation involving 63 000 women. Results—The conditions considered in the analysis were conjunctivitis, keratitis, iritis, lacrimal disease, strabismus, cataract, glaucoma, retinal detachment, and retinal vascular lesions. With the exception of retinal vascular lesions, there was no consistent evidence of important increases in risk of eye diseases in users of Oral Contraception. There was about a twofold increase in the risk of retinal vascular lesions in recent pill users in both studies (statistically significant only in the RCGP study). The increase was not limited to any specific type of lesion and may well reflect diagnostic bias. Conclusion—Oral contraceptive use does not appear to increase the risk of eye disease, with the possible exception of retinal vascular lesions.