Statins: More Good News
In the current issue of the journal Circulation, the impact of the cholesterol-lowering drug simvastatin on aortic (the large artery that arises directly from the heart) and carotid artery narrowing was assessed using magnetic resonance scanning. The statin class of drugs reduce the blood levels of “bad cholesterol” (LDL), and increase levels of “good cholesterol” (HDL). These medications have also been shown to reduce the blood levels of a protein linked to inflammation of diseased blood vessels (C-reactive protein), and to the progression of cardiovascular disease. While these drugs have been prescribed in order to reduce the likelihood of developing cardiovascular disease, their effects on preexisting arterial disease are less clear. In this study, the authors used a magnetic resonance imaging (MRI) scanner to measure arterial narrowing in 21 patients with elevated blood cholesterol levels.
At the beginning of the study, a total of 44 aortic and 32 carotid artery plaques were found in the 21 volunteers. All patients took simvastatin during the 2-year study period, and their aortas and carotid arteries were periodically reevaluated by MRI scanning. Following 12 months of simvastatin therapy, there was a 10% reduction in the thickness of the aortic wall thickness and an 8% reduction in carotid artery wall thickness. Additional average reductions in arterial wall thickness, ranging from 12-20%, were achieved following 18-24 months of simvastatin therapy. This study, therefore, shows that long-term treatment with simvastatin can not only slow down the progression of arterial atherosclerosis (narrowing of arteries due to cholesterol plaque formation), but may also actually help to reverse such pathologic changes.
Tamoxifen & Carotid Artery Wall Thickness
The journal Circulation contains another interesting study. The drug Tamoxifen is often used to treat women with breast cancers that are sensitive to the female hormone estrogen. Tamoxifen selectively blocks the effects of estrogen on breast milk duct cells, thus reducing estrogen’s stimulatory effects on breast cell growth. Tamoxifen has also been shown to reduce the risk of breast cancer by nearly 50% in women without a history of breast cancer, but with a history of preexisting risk factors for the disease. At the same time, Tamoxifen can mimic the effects of estrogen in certain tissues of the body, such as the bones and the uterus. The study looked at the effects of Tamoxifen on the thickness of the carotid artery. As cardiovascular disease progresses, the arterial walls become thicker, thus reducing the internal arterial diameter and, in time, limiting blood flow through the narrowed blood vessels.
A total of 67 women taking Tamoxifen for breast cancer were compared with 37 breast cancer patients who were not taking the anti-estrogen drug. The women were studied for an average of 2.4 years. Ultrasound measurements of the carotid arteries were performed at regular intervals. The study found that the women who took Tamoxifen had significantly less arterial thickening than the women who were not taking Tamoxifen. The reduction in carotid artery thickening among the patients taking Tamoxifen was nearly equivalent to the amount of thickening that naturally occurs in adults over a 12-year period. This apparent cardiovascular protective effect of Tamoxifen is an intriguing finding in view of recent studies showing an increase in the incidence of cardiovascular disease among women who take supplemental estrogen (hormone replacement therapy) after menopause. Ultimately, only a large well-controlled study will be able to confirm the findings of this small preliminary study, and reveal whether or not the observed effects of Tamoxifen on arterial wall thickness actually translate into improvements in health outcomes.
Coffee & Gallstones?
Gallstone disease, or cholelithiasis, is a painful and occasionally life-threatening disease that arises when hard cholesterol stones form in the gallbladder. The gallbladder collects and concentrates bile from the liver, and then forcefully injects this concentrated bile into the intestinal tract during meals, where it helps to improve the absorption of dietary fats into the blood. Cholelithiasis affects women more than twice as often as men, most likely due to the effects of estrogen and pregnancy. Nearly 15 million American women have gallstone disease, while about 7 million men have this condition, or about 10-20% of the population. Nearly 1 million people will undergo surgery this year to have their gallstones and gallbladders removed. In addition to gender, obesity, increasing age, and number of previous full-term pregnancies are also linked with an increase in the risk of gallstone disease.
There is some data suggesting that coffee consumption may reduce the risk of gallstone disease. A new study in the current issue of the journal Gastroenterology looks at this possible link between coffee and gallstone disease. Nearly 81,000 women, aged 34-59 years, were enrolled into this study in 1980. Biennial surveys were taken from all patients, and the women’s coffee consumption and the incidence of gallbladder surgery were then analyzed. During the subsequent 20 years of follow-up, 7,811 of the study women underwent surgery for gallstone disease. The study determined that drinking 2-3 cups of coffee per day reduced the risk of cholelithiasis by 22%, while 4 cups of java per day reduced the risk of gallstone disease by 28%. Drinking 1 cup of coffee per day reduced the risk of cholelithiasis by only about 9%. The consumption of other caffeinated beverages also reduced the risk of gallstone disease, while decaffeinated coffee had no impact on gallstone risk. Thus, it appears that the chronic consumption of caffeinated beverages, including coffee, may be able to moderately reduce the risk of cholelithiasis.
Irritable Bowel Syndrome Update
Irritable bowel syndrome (IBS) affects as many as 20% of the population in the United States. As with cholelithiasis, more than twice as many women as men have been diagnosed with IBS. IBS is characterized by bouts of abdominal cramping and diarrhea, often alternating with periods of constipation. While many theories have been advanced as to the cause of IBS, the etiology is not known. As no physical cause for IBS has ever been convincingly demonstrated, IBS is characterized as a “functional disorder.” A new study in the current issue of Gastroenterology used a surgical approach to obtain biopsies of the small intestines of patients with IBS symptoms. A total of 10 patients (2 men and 8 women) were evaluated. In 9 out of the 10 patients, the intestinal biopsies revealed signs of inflammation involving the nerve cells within the intestinal wall, known as the myenteric plexus. Six of these 9 patients were also found to have nerve cell degeneration within the myenteric plexus. Although the reasons behind these intriguing findings are not yet clear, this small study does appear to show distinctive anatomic changes of the small intestine in patients with IBS. Further study will, therefore, be necessary to reproduce the findings of this small preliminary study, and to better understand why these nerve cell abnormalities arise in the intestines of IBS patients.
Dr. Robert A. Wascher
