- Genetic Testing Predicts Who Will Have Side Effects from Statin Drugs
- Low Levels of Good Cholesterol (HDL) Are Linked to Poor Memory
- Cipro and Similar Antibiotics Can Cause Tendon Pain or Rupture
- A Better Cholesterol Test
- Diabetes Rate Climbs to 8% of Americans
Genetic Testing Predicts Who Will Have Side Effects from Statin Drugs
Researchers have identified a gene that makes some people more likely than others to have side effects from cholesterol medicines called "statins." A study describing the findings was published online by the New England Journal of Medicine on July 23.
Statin cholesterol drugs occasionally cause muscle pain and weakness (myopathy), which can be severe. Commonly prescribed statins include atorvastatin (Lipitor), fluvastatin (Lescol), lovastatin (Mevacor), simvastatin (Zocor), pravastatin (Pravachol) and rosuvastatin (Crestor). Approximately one out of every 10,000 patients who take a middle-range dose of a statin drug experience this side effect each year. It occurs much more frequently in people who take a high dose of a statin.
Researchers wanted to see if some people were genetically predisposed to this serious reaction. They compared the genes of 85 people who were taking a statin and developed myopathy with the genes of 90 people who did not experience myopathy while taking a statin. Both groups of patients were similar in terms of sex, age, estimated kidney function. The groups were also alike in terms of other medicines that they took regularly.
A gene on chromosome 12 appears to control how much statin enters the liver. Eighty-five percent of the general population have two normal copies of this gene, but 15% of people have a variation in one or both copies. Sixty-six or almost 80% of the people who had muscle symptoms had the variation for at least one of their genes. Because the gene is present in so many of the patients who have myopathy, it is very likely that this gene is predisposing people to have this painful drug reaction. The researchers calculated that if a person has one copy of the gene with the variation, then the risk for myopathy is roughly quadrupled compared with people who have two normal copies of the gene. If a person has two copies of the gene with the variation, then the risk is about 17 times normal.
Using genetic tests to predict a person's response to a medicine is called "pharmacogenomics." Genetic testing is likely to be requested in the future before a statin is started, or before the dose of a medicine is increased. In this way, people who have one or two copies of the gene variation can avoid statins (especially at a high dose).
Low Levels of HDL ("Good" Cholesterol Are Linked to Poor Memory
If your high-density lipoprotein (HDL) levels are low in middle age, your memory may be poorer than it normally would be. This is the finding of a study that was released online on June 30 by Arteriosclerosis, Thrombosis and Vascular Biology: Journal of the American Heart Association.
Researchers gave 3,673 middle-age people a short-term memory test when the study began. The average age of the participants at that time was 55. Participants listened to a list of 20 words, then were asked to write down as many as they could remember. The group was re-tested five years later. Cholesterol was measured at the time of each memory test.
Word-recall tests are not a perfect measure of memory, yet the study results are interesting. The initial memory test showed that people who had a low HDL (less than 40 milligrams per deciliter, mg/dL) scored 27% lower on their word-recall test compared with people who had HDL levels above 60 mg/dL. Most people in the study did not have significant changes in their HDL levels between the first and second tests. Five years after the first test, people with low HDL scored on average 53% lower on the memory test compared with people who had high HDL levels. In other words, the relationship between low HDL and poor memory was "magnified" as the group aged.
This study shows that there is a connection between HDL and memory, but not that low HDL causes poor memory. Statins can improve HDL, but aren't recommended if HDL is your only cholesterol abnormality. Boost your HDL level by making healthy changes in your lifestyle instead. Regular exercise helps your HDL level. The kinds of fats that you eat in your diet also matter: Reduce saturated fats and trans fats (which are found in hydrogenated and partially-hydrogenated vegetable oils) in your diet, and eat monounsaturated fats, such as olive oil, canola oil and peanut oils.
Cipro and Similar Antibiotics Can Cause Tendon Pain or Rupture
A group of antibiotics that are commonly prescribed for bacterial infections, such as urinary tract infections, pneumonia and skin infections, can cause curious but damaging side effects — tendonitis and tendon rupture. On July 8, the U.S. Food and Drug Administration (FDA) issued a new online alert to doctors and the public that went beyond an earlier notice about this concern. The new alert warned that these side effects may be more common than originally recognized.
The medicines in question are in the drug family known as fluoroquinolones. They include ciprofloxacin (Cipro, Proquin), levofloxacin (Levaquin), moxifloxacin (Avelox), gemifloxacin (Factive), norfloxacin (Noroxin) and ofloxacin (Floxin).
During treatment or within several months of their use, the drugs can trigger inflammation and, in some cases, rupture of a tendon. The most commonly affected tendon is the Achilles tendon, which is located at the back of the ankle. A ruptured Achilles tendon requires surgery to fix the damage. Other tendons that have been affected by these medications include the rotator cuff of the shoulder, the biceps tendon in the arm, and tendons in the hand and thumb. People are at greater risk of this side effect if they are over age 60, have had a heart, lung, or kidney transplant, or are taking corticosteroids, such as prednisone.
If you notice pain, swelling or redness in your ankle, shoulder or hand within three months after you have taken one of these antibiotics, stop using the medication, avoid exercising the painful area and contact your doctor.
A Better Cholesterol Test.
In the July 19 issue of Lancet, experts propose a new way for doctors to monitor your cholesterol levels and more accurately predict your heart-attack risk. They suggest measuring the concentration of protein particles in your blood called "apolipoprotein B100" (ApoB)and "apolipoprotein A1" (ApoA1). They may be more important to your heart risk than is cholesterol itself. To travel through your bloodstream, cholesterol combines with certain proteins to form particles called "lipoproteins." The two main types of lipoproteins are "low density" and "high density." They are also known as your "bad" cholesterol (LDL) and "good" cholesterol (HDL). Technically, LDL and HDL aren't themselves cholesterol. They are the small bundles that form and carry cholesterol through the body. ApoB is one of the proteins on LDL particles. HDL packages cholesterol with different proteins, including ApoA1.
The ratio of ApoB protein to ApoA1 protein is very closely linked to heart attack risk. In a study that measured LDL, HDL, ApoB and ApoA1 levels, researchers compared 9,345 people who had heart attacks with 12,120 individuals who were of similar age and gender, but who hadn't had heart attacks. The ratio of ApoB to ApoA1 predicted heart attack risk better than did the ratio of LDL to HDL, or total cholesterol to HDL.
Within the next few years, doctors may begin to report your cholesterol results differently, with a new focus on your ApoB to ApoA1 ratio. Medicines that lower LDL also reduce ApoB proteins, so treatments will not change. The other good news is that ApoB and ApoA1 can be measured with a random blood sample; they do not require a fasting test.
Diabetes Rate Climbs to 8% of Americans.
On June 24, statisticians from the U.S. Centers for Disease Control and Prevention(CDC) estimated that the total number of Americans with diabetes had climbed to 24 million in 2007, an increase of 3 million since 2005. The new number equals 8% of the U.S. population, including Americans of all ages. The rate of diabetes among mature adults is even more alarming. Almost 25% of Americans age 60 or older had diabetes in 2007. About 57 million people have pre-diabetes, a condition that makes you more likely to develop diabetes. People with pre-diabetes have mild elevations in blood sugar caused by resistance to the effects of insulin. Diabetes runs in families, but most experts agree that this increase in diabetes is due to poor weight control, poor diet and not enough exercise among Americans.
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