SLEEP, MELATONIN & BREAST CANCER RISK
It has been previously hypothesized that women who sleep longer at night may have a decreased risk of developing breast cancer when compared to those who spend less time sleeping. Although previous clinical research has not yet validated this hypothesis, some researchers have still speculated that the increased production of the hormone melatonin in the brain during sleep may confer some measure of protection against breast cancer. Melatonin, which is secreted in an area of the brain that helps to regulate our 24-hour circadian rhythm (wake-sleep cycle), is also thought to have some anti-cancer properties. Several studies have appeared to show an increased risk of breast cancer, and other cancers, among people who work night shifts or rotating shifts, leading some researchers to propose that decreased levels of melatonin might be at least partially responsible for this increase in cancer risk (melatonin levels decrease when humans are exposed to light at night).
new clinical research trial
In this study, more than 33,000 Singaporean women enrolled in the Singapore Chinese Health Study were studied for an average of 11 years. During this period, 525 of the women were diagnosed with breast cancer. All women entering into this study had completed surveys regarding their sleep habits, and the women also had their urine tested for melatonin metabolites.
In this study, women who slept an average of 9 or more hours per night were found to be 33% less likely to be diagnosed with breast cancer when compared to women who slept 6 or fewer hours per night. When melatonin levels were assessed, the women who slept 9 or more hours per night were found to have 42% higher levels of melatonin in their bodies when compared to the women who slept 6 or fewer hours per night. The authors of this study, therefore, hypothesized that the women who slept longer hours each night might have experienced a lower incidence of breast cancer due to higher melatonin levels in their bodies.
This is an intriguing study, although it certainly does not prove that increased durations of sleep directly or indirectly reduce breast cancer risk via increased levels of melatonin (or, stated another way, that a chronically decreased duration of sleep increases breast cancer risk through a reduction in melatonin production). Simply because two or more separate factors are observed to occur together does not prove that they are causally linked to each other. That being said, this study should stimulate the development of a prospective clinical research trial looking at the effects of melatonin supplementation on women who are either at high risk of developing breast cancer, or women who have already been diagnosed with breast cancer. As there are several other previous studies that have linked chronically inadequate levels of sleep to higher overall mortality, it seems prudent to recommend that one gets an average of at least 7 to 8 hours of sleep per night.
MEDITERRANEAN DIET & CANCER RISK
Many beneficial health effects have been attributed to the so-called Mediterranean diet, including a decreased incidence of cardiovascular disease and cancer (please see my recent Archives for a review of a related clinical study). Generally speaking, a Mediterranean diet is based upon moderate-to-high levels of consumption of the following foods: olive oil, fresh fruits and vegetables, unrefined grains, cheese, yogurt, fish and red wine. At the same time, saturated fats, red meat, and processed meat products are consumed very infrequently.
A new clinical research
trial, just published in the British Journal
of Cancer, looked at effects of following the
Mediterranean diet on cancer risk among more than 25,000 Greek men and
participating in the “European Prospective Investigation into Cancer
nutrition” (EPIC) trial. Participating
research institutions included the
All participants in this clinical study completed extensive questionnaires, including dietary surveys, upon entry into the research trial. The extent of adherence to a Mediterranean diet was assessed by a 10-point scale, where a score of “0” indicated minimal adherence, and a score of “9” indicated maximal adherence. During an average follow-up period of almost 8 years, 851 cases of cancer were diagnosed among these more than 25,000 Greek adults.
When all of the data from this large public health study was evaluated, it was found that each 2-point increase in adherence to a Mediterranean diet was associated with a 12% reduction in the risk of cancer (the anti-cancer effects of a Mediterranean diet also appeared more pronounced in women than in men, in this study). Based upon previous research findings, the scientists in this study determined that the extent of cancer reduction associated with adherence to a Mediterranean diet was greater than would have been expected for each individual food item consumed in a typical Mediterranean diet, suggesting that added cancer-reducing benefits might arise from certain combinations of foods when eaten together.
As with all survey-based public health studies, biases on the part of those taking the surveys and those administering them (as well as the people who actually designed the surveys) are potential sources of inaccurate data. However, this fine epidemiological study adds to a growing list of clinical research data suggesting that following a Mediterranean diet may significantly reduce your risk of cardiovascular disease and cancer. I see little downside to adopting a Mediterranean-style diet, assuming, of course, that you drink red wine only in moderation.
NEW TREATMENT FOR VARICOSE VEINS
Varicose veins in the legs and feet are a common and annoying health problem, especially among people who spend a great deal of time standing. A variety of treatments are available to treat varicose veins, although most advanced cases will usually require surgery of some sort. Even with aggressive surgery, however, varicose veins can return in as many as 40% of cases.
In those patients who
undergo surgical removal of their painful, itching
and unsightly varicose veins, most will undergo a procedure referred to
saphenofemoral junction ligation and division.
This procedure involves individually dividing the 5 or
more dilated superficial
leg veins that empty blood into the deeper and larger femoral vein. In the majority of cases
where varicose veins
recur after surgery, the divided superficial veins appear to have
re-established a connection with the femoral vein.
A new clinical research trial, published in
the journal Circulation, evaluates
new surgical procedure that involves the insertion of a physical
between the femoral vein and the divided superficial venous tributaries
attempt to reduce the risk of recurrence.
This study was carried out at the
In this study, 292 patients were prospectively randomized to undergo standard varicose vein surgery either with or without the placement of a Teflon patch between the divided veins. All patients underwent serial postoperative studies of their lower extremity veins for a period of 36 months. The researchers discovered that, at 3 years following surgery, the incidence of recurrent varicose veins was twice as common in the patients who had not received the Teflon patch. Among those patients who did receive the Teflon patch and who still developed recurrent varicose veins, repeat surgery demonstrated that new venous connections developed by detouring around the implanted Teflon patch.
This innovative and prospectively conducted surgical study showed that the risk of recurrent varicose veins can effectively be cut in half, at 3 years following surgery, by interposing a Teflon patch between the divided veins at the time of the initial varicose vein surgery. Further research may lead to further refinements in the Teflon patch technique used in this study in an effort to further reduce the incidence of varicose vein recurrence following surgery.
Dr. Wascher is an oncologic surgeon, professor of surgery, a widely published author, and the Director of the Division of Surgical Oncology at Newark Beth Israel Medical Center
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Copyright 2008. Robert A. Wascher, MD, FACS. All rights reserved.
Dr. Wascher's Archives:
4-27-2008: Stents vs. Bypass Surgery for Coronary Artery Disease; The “DASH” Hypertension Diet & Cardiovascular Disease Prevention; Testosterone Therapy for Women with Decreased Sexual Desire & Function
4-6-2008: Human Papilloma Virus (HPV), Pap Smear Results & Cervical Cancer; Human Papilloma Virus (HPV) Infection & Oral Cancer; Hormone Replacement Therapy (HRT) & the Risk of Gastroesophageal Reflux Disorder (GERD)
12-16-2007: Honey vs. Dextromethorphan vs. No Treatment for Kids with Night-Time Cough, Acupuncture & Hot Flashes in Women with Breast Cancer, Physical Activity & the Risk of Death, Mediterranean Diet & Mortality