Statin Drugs & Death Rates; Physical Activity, Breast Cancer & Sex Hormones
Posted Feb 15 2009 1:58pm
Statin Drugs & Death Rates
Physical Activity, Breast Cancer & Sex Hormones
"A critical weekly review of important new research findings for health-conscious readers..."
By, Robert A. Wascher, MD, FACS
Last Updated: 02/15/2009
The information in this column is intended for informational purposes only, and does not constitute medical advice or recommendations by the author. Please consult with your physician before making any lifestyle or medication changes, or if you have any other concerns regarding your health.
STATIN DRUGS AND DEATH RATES
As I’ve mentioned in previous columns, the statin class of cholesterol-lowering drugs have revolutionized the treatment of elevated cholesterol levels, and have been shown, by multiple clinical studies, to decrease the incidence of cardiovascular events, including fatal heart attacks (myocardial infarction), in susceptible patients. While their value in reducing non-cardiovascular disease events (such as cancer, for example) continues to be debated, there is no question but that statin drugs can significantly drive down the risk of coronary artery disease in patients with elevated cholesterol levels, as well as in patients with high-normal levels of LDL (the “bad cholesterol”).
A new clinical study assessing statin drugs and death rates has just been published in the Archives of Internal Medicine. Nearly 230,000 adult patients (average age was about 58 years) enrolled in an HMO were retrospectively assessed in this huge public health study, which was performed in Israel; and all of these patients were started on statin medications between 1998 and 2006. Two general groups of patients were included in this study. The first group included patients who were prescribed statin drugs to prevent coronary artery disease, and who had no clinical evidence of coronary artery disease at the time they started receiving statins. The second group consisted of patients who were prescribed statin drugs because they already had been diagnosed with coronary artery disease. In this study, the researchers were able to determine the level of compliance of each patient with their statin medications, based upon the HMO’s pharmacy refill data.
After an average follow-up of about 5 years, the death rates among the compliant and noncompliant patients were then compared. The patients who were at least 90 percent compliant with their statin prescriptions experienced a whopping 45 percent reduction in their risk of death, from any cause, when compared to the patients who were less than 10 percent compliant with their statin medications! Furthermore, this dramatic difference in survival was observed in both the prevention group and in the coronary artery disease group.
The research data also revealed that the greatest reduction in the risk of death was observed in patients with very high baseline LDL levels, and in patients treated with more potent statin drugs. These latter two observations are especially important, because the retrospective nature of this study increases the risk that undetected biases might have influenced the researchers’ conclusions. (For example, patients who were noncompliant with their statin drugs may have also engaged in other risky health behaviors that, independent of not taking their statin drugs, might also have increased their risk of death.)
The 45 percent reduction in all-cause mortality that was associated, in this study, with a greater than 90 percent patient compliance rate with statin prescriptions is significantly greater than has been observed in most prospective randomized clinical research studies, to date. Given the retrospective nature of this study, it is not clear if the much greater mortality benefit of statin drug compliance observed in this study is entirely valid or not, but the enormous population of HMO patients included in this study, and the moderately long duration of their follow-up (albeit retrospective in nature), suggests that this study’s conclusions are probably reasonable.
If you have significant risk factors for coronary artery disease, or if you already have coronary artery disease, and your doctor has prescribed a statin drug for you, then the results of this study suggest that you can markedly reduce your risk of death by taking your medications as prescribed.
PHYSICAL ACTIVITY, BREAST CANCER & SEX HORMONES
There is considerable research evidence showing that regular exercise decreases the risk of several different types of cancer, including breast cancer. In the case of breast cancer, given that 85 to 90 percent of breast cancer cases appear to be linked in some way to exposure to estrogen and progesterone (the “female sex hormones”), most experts have assumed that increased levels of regular physical activity must somehow affect circulating sex hormone levels in the blood, but the research data in this area has been unclear. However, a new clinical research study, published in the journalCancer Epidemiology Biomarkers & Prevention, now appears to provide evidence of a direct link between exercise and circulating sex hormone levels in the blood.
In this study, more than 800 postmenopausal women who participated in a large European public health study, the EPIC study, were evaluated. Physical activity data for these women was obtained by the use of patient questionnaires, and blood was drawn from all study participants and tested for levels of both female and male sex hormones.
The investigators soon discovered that increasing levels of physical activity resulted in decreasing levels of estrogen in the blood, as well as increased levels of a protein in the blood that binds up circulating sex hormones (sex hormone binding globulin). Furthermore, high levels of physical activity, as occurs with vigorous exercise, also increased blood levels of the male sex hormone dehydroepiandrosterone (DHEA) in these postmenopausal women.
The results of this study offer at least one potential explanation for the inverse relationship between levels of physical activity and breast cancer risk that has been identified in previous clinical studies. Irrespective of the precise mechanism(s) involved, there is ample evidence that 4 to 5 thirty-minute periods of moderate-to-vigorous exercise each week can significantly reduce a woman’s risk of developing breast cancer, and that this exercise-related risk reduction is present irrespective of whether a woman is overweight or not. Also, as we all know, exercise is good for both the heart and mind, as well!
Disclaimer: As always, my advice to readers is to seek the advice of your physicianbeforemaking any significant changes in medications, diet, or level of physical activity
Dr. Wascher is an oncologic surgeon, a professor of surgery, a widely published author, and a Surgical Oncologist at the Kaiser Permanente healthcare system in Orange County, California