Value of Aspirin: IMPORTANT
Posted 4/6/2010
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My husband casually asked me last week if I continue to take a daily aspirin. I do, and these studies give me a new reason to do so. Like everything else, this is an "ask your doctor" situation as there are some women who probably should not do so. For the rest of us, supply yourself with a bottle of this low-tech, been-around-a-long-time tablet and take one a day. Here it is from Medscape:
Aspirin, Analgesic Use Linked to Lower Estrogen
Levels in Postmenopausal Women
March 31, 2010 — Postmenopausal women who are regular users of aspirin and other analgesics may have lower estrogen levels vs nonusers, which could potentially lower the risk for breast or ovarian cancer, according to the results of a study reported online March 23 in Cancer Epidemiology, Biomarkers & Prevention. A second study in the March 20 issue of the Journal of Clinical Oncology suggests that among women living at least 1 year after a breast cancer diagnosis, aspirin use is linked to a reduced risk for distant recurrence and breast cancer death.
First Study: Decrease in Estrogen Levels from Aspirin Use
"Prior epidemiologic studies suggest that regular use of analgesics may decrease risk of breast and ovarian cancer," write Margaret A. Gates, ScD, from Brigham and Women's Hospital and Harvard Medical School in Boston, Massachusetts, and colleagues. "We explored possible hormone-mediated mechanisms for these associations by examining the relationship between use of aspirin, nonaspirin nonsteroidal anti-inflammatory drugs (NSAID), and acetaminophen and sex steroid hormone concentrations among 740 postmenopausal women in the Nurses' Health Study." For each category of self-reported analgesic use in 1988 or 1990, the investigators calculated adjusted geometric mean estrogen and androgen levels from blood samples collected from 1989 to 1990. Days of use per month of aspirin, nonaspirin NSAIDs, or acetaminophen in 1990 were not significantly associated with hormone levels (all P for trend ≥ .09). However, there were significant inverse trends between the estimated number of aspirin tablets per month in 1988 and concentrations of estrone (P for trend = .04) and estrone sulfate (P for trend = .03).
Compared with women with no NSAID use, women who used NSAIDs 15 days per month or more had significantly lower levels of estradiol (P for trend = .03), based on analyses of total aspirin and nonaspirin NSAID use in 1990. For all analgesics (aspirin, nonaspirin NSAIDs, and acetaminophen), frequency of use in 1990 was inversely associated with concentrations of estradiol (P for trend = .001), free estradiol (P for trend = .01), estrone sulfate (P for trend = .03), and the ratio of estradiol to testosterone (P for trend = .04).
"Among postmenopausal women, regular users of aspirin and other analgesics may have lower estrogen levels than nonusers, which could contribute to a decreased risk of breast or ovarian cancer among analgesic users," the study authors write.
Limitations of this study include unavailability of information on the exact frequency of use or dose of each analgesic in 1990, availability of only a single blood sample for each woman, inadequate power to detect small differences in hormone levels, and cross-sectional design precluding determination of causality. In addition, unstudied conditions may have confounded the associations.
"Additional research is needed to confirm this association and to determine whether the decrease in estrogen concentrations due to analgesic use translates to a lower risk of breast or ovarian cancer," the study authors write. "Randomized trials of aspirin, nonaspirin NSAID, and acetaminophen use and changes in hormone levels would be a
logical next step in elucidating these associations, including the magnitude of the effect, the most beneficial analgesics,and the relevant dose. This research may have important public health implications if an inverse association betweenanalgesic use and risk of breast or ovarian cancer is confirmed, as analgesics could be easily implemented as a chemopreventive and may decrease risk of several cancers."
Second Study Finds Similar Results
The second study, by Michelle D. Holmes, MD, PhD, also from Brigham and Women's Hospital and Harvard Medical School, and colleagues, looked at aspirin intake and survival duration after breast cancer. This prospective, observational study was based on responses from 4164 female registered nurses in the Nurses' Health Study who were diagnosed with stages I, II, or III breast cancer between 1976 and 2002. Follow-up continued until death or June 2006, whichever came first. The primary study endpoint was breast cancer mortality risk according to the number of days per week of aspirin use.
Aspirin use was associated with a decreased risk for breast cancer death, with adjusted relative risks (RRs) for 1, 2 to 5, and 6 to 7 days of aspirin use per week vs no use of 1.07 (95% CI, 0.70 - 1.63), 0.29 (95% CI, 0.16 - 0.52), and 0.36 (95% CI, 0.24 - 0.54), respectively (test for linear trend, P < .001). Stage, menopausal status, body mass index, or estrogen receptor status did not significantly affect this association. For distant recurrence, the findings were similar.
"Among women living at least 1 year after a breast cancer diagnosis, aspirin use was associated with a decreased riskof distant recurrence and breast cancer death," the study authors write.
Limitations of this study include observational design, reliance on self-report, lack of details on aspirin dose, confounding, and limited generalizability.
"The ability to affect length and quality of life after breast cancer by a common medication would be welcome," the study authors conclude. "Further studies are needed to determine the possible mechanism of aspirin's action, including perhaps ultimately, a randomized trial of aspirin use after breast cancer diagnosis with survival as the end point. If confirmed, our results may broaden the scope of interventions available to reduce breast cancer-related morbidity and mortality."
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