Researchers released a study this week that looked at multiple embryo transfers for in vitro fertilization. They found that transferring a third embryo does not improve the odds of having a baby. Other new studies found that marathon deaths are rare but increasing and that women who take statin drugs may have a higher risk of diabetes. A fourth study lasted 20 years. It found that people who smoked up to a joint of pot a week had no increased risk of lung damage.
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Study: 3rd Embryo Doesn't Boost Success Rate
Receiving 3 embryos by in vitro fertilization (IVF) is no more likely to produce a baby than receiving 2, a study released this week found. But it does increase the odds of riskier multiple births. The study looked at 124,000 IVF treatments, or "cycles," in the United Kingdom. Each involved the transfer of one or more embryos. The treatments led to 33,000 live births. The live birth rate was 33% for women under 40 who received 2 embryos and 25% for 3 embryos. Among women over 40, the live birth rate was 13% with either 2 or 3 embryos. Guidelines on the number of embryos transferred are much stricter in the UK and the rest of Europe than in the United States. In the UK, 65% of transfers in 2010 involved 2 embryos. About 31% used a single embryo and 4% used 3. U.S. numbers from 2009 are quite different. About 52% of transfers involved 2 embryos. About 23% used 3 and 12% used 4 or more. Only about 14% transferred a single embryo. The journal Lancet published the study. The Associated Press wrote about it January 12.

Marathon Deaths Rare but Rising
It's rare for a marathon runner to collapse because of the heart stopping, researchers said this week. But cases are increasing as more people try to run marathons, they said. Researchers looked for cases by reading news reports and checking with medical staff of marathons and half-marathons. They counted 59 cases of cardiac arrest during the 2000s. All but 8 were men. The runners collapsed with no pulse during the race or within an hour after finishing it. In all, 42 died. This equals 1 cardiac arrest per 184,000 runners and 1 death per 259,000. This is a lower rate than for many other sports, researchers said. Cases increased during the last half of the study period because more people have been running marathons, they said. A cause was recorded for 31 cardiac arrests. In most of them, the cause was narrowed arteries or a heart muscle disease, cardiomyopathy. Most people were not aware they had these conditions. The New England Journal of Medicine published the study. Canadian Press wrote about it January 12.

Study: Statins May Raise Diabetes Risk
Women who use statin drugs may have a higher risk of developing diabetes, a large study published this week finds. The results reinforce smaller studies that found a similar link for both women and men. But experts say people at risk of heart attacks should still take the drugs because the benefits clearly outweigh the risks. Statins lower LDL cholesterol in the blood. Studies show they reduce the risk of heart attack, stroke and early death for high-risk people. The new study included more than 153,000 women. All were in their 50s or older. They were part of a long-running health study. When the study began, about 7% took statins. Researchers collected health information from them for 7 to 15 years. By 2005, about 10% of the statin users had developed diabetes. Only 6.4% of those who did not use statins had developed the disease. The journal Archives of Internal Medicine published the study. The Associated Press wrote about it.

Study: Long-Term Pot Use Doesn't Harm Lungs
Smoking marijuana once a week for up to 20 years does not appear to harm lung function, a study released this week concluded. The study included 5,115 adults who were under age 30 when it began. They were asked from time to time about use of marijuana and tobacco. Cigarette users smoked about 9 per day. Marijuana users averaged 1 or 2 joints a few times a month. In the next 20 years, they also had several tests of lung function. Researchers calculated the effects of tobacco and pot separately. Smoking cigarettes did harm lung function. Marijuana did not. Smoking as much as 1 joint daily for 7 years did not affect lung function test scores. Nor did smoking 1 joint weekly for 20 years. Very few people smoked pot more often. Researchers said they could not explain the results. They noted that THC, which produces the "high" from marijuana, tends to reduce inflammation. This might counteract the effects of other chemicals in the smoke. They also noted that people inhale deeply when smoking pot. This might provide an advantage on lung function tests. The Journal of the American Medical Association published the study. The Associated Press wrote about it.

Used with the permission of the copyright owner. All rights reserved. The above summaries are not intended to provide advice on personal medical matters, nor are they intended to be a substitute for consultation with a physician.