Aspirin use among women physicians in the United States.

T have been limited studies of aspirin use in any population. The Atherosclerosis Risk in Communities Investigators1 reported regular aspirin use in 10% of adults with only 3% of adults receiving aspirin for specific cardiovascular indications in 1996. A 1989 community survey in Canada2 reported prevalence of long-term aspirin use in subjects .50 years old to be 19% and 14% among men and women, respectively. In the Nurses’ Survey,3 data collected from 1980 to 1986 found that ,10% of women who reported regular aspirin use followed this practice for primary prevention of cardiovascular disease. To date there have been no studies that have specifically examined aspirin use among female physicians. In this report, we address this question using the Women Physicians’ Health Study, a national study of 4,501 women physicians in the United States. • • • The design and methods of the Women Physicians’ Health Study and the basic characteristics of the population have been previously described.4–6 The Women Physicians’ Health Study surveyed a stratified, random sample of US women MDs; the sampling frame is based on the American Medical Association’s Physician Masterfile, a database intended to record all MDs residing in the US and its possessions. Using a sampling scheme stratified by decade of graduation from medical school, we randomly selected 2,500 women from each of the last 4 decades’ graduating classes (1950 to 1989). We over-sampled older women physicians, a population that would otherwise have been sparsely represented by proportional allocation because of the recent increase in numbers of women physicians. We included active, part-time, professionally inactive, and retired physicians, aged 30 to 70, who were not in residency training programs in September 1993, when the sampling frame was constructed. In that month, the first of 4 mailings was sent out; each mailing contained a cover letter and a self-administered 4-page questionnaire. Enrollment was closed in October 1994 (final n 5 4,501). Of the potential respondents, an estimated 23% were ineligible to participate because their addresses were wrong, or they were men, deceased, living out of the country, or interns or residents. Our response rate was 59% of physicians eligible to participate. We compared respondents and nonrespondents in 3 ways: we used our phone survey (comparing our phonesurveyed random sample of 200 nonrespondents with all the written survey respondents), the American Medical Association Physician Masterfile (contrasting all respondents with all nonrespondents), and an examination of survey mailing waves (all respondents, from waves 1 through 4) to compare respondents and nonrespondents regarding a large number of key variables. From these 3 investigations, we found that nonrespondents were less likely than were respondents to be board certified. However, respondents and nonrespondents did not consistently or substantively differ on other tested measures, including age, ethnicity, marital status, number of children, alcohol consumption, fat intake, exercise, smoking status, hours worked per week, frequency of being a primary care practitioner, personal income, or percentage actively practicing medicine. Based on these findings, we weighted the data by decade of graduation (to adjust for our stratified sampling scheme), and by decade-specific response rate and board certification status (to adjust for our identified response bias). The analysis weights (within decade) for board-certified and non–board-certified respondents were 3.4 and 5.5 (1950s), 9.3 and 17.7 (1960s), 17.9 and 36.5 (1970s), and 28.3 and 63.9 (1980s), respectively. Using these weights allowed us to make inferences to the entire population of women physicians who graduated from medical school between 1950 and 1989. The percentage of women physicians (n 5 4,055) who never used aspirin was 63.3% (SE 5 0.9); 6.1% used aspirin on a daily basis. Although age and specialty were major determinants of regular aspirin use, there was no significant variation in the prevalence of aspirin use by ethnicity (Table I). There was also a significant increase in regular aspirin use among physicians .50 years of age with cardiovascular risk factors, such as systemic hypertension, hypercholesterolemia, and family history of coronary artery disease, although this relation was not as significant among the younger cohort. Similarly, 42.8% of those .50 years old with known coronary artery disease used aspirin regularly, whereas only 21% of those #50 years old and with coronary artery disease did so. Those who were born in the US were more likely to use aspirin and to use it on a daily basis (data not shown). We found (not shown) no relation between aspirin use and being a Massachusetts resident (Massachusetts being the home state of the Physicians’ Health Study, which examined aspirin use in male physicians). • • • In our study, 6.1% of women physicians used aspirin at least once a day, and an additional 30.5% of them used aspirin regularly, but less than once a day. From the Division of Preventive Medicine, Department of Family and Preventive Medicine, and Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia. Dr. Frank’s address is: 69 Butler St., S.E., Atlanta, Georgia 303033219. E-mail: efrank@fpm.eushc.org. Manuscript received December 27, 1999; revised manuscript received and accepted March 6, 2000.