Harvard Health Content API

About 1 in 4 U.S. teenage girls has a sexually transmitted disease, a study has found. About half the girls in the study said they had had sexual intercourse. The rate of STDs was about 4 in 10 for those girls. The study was conducted by the U.S. Centers for Disease Control and Prevention. It included 838 teen girls who had taken part in a national health survey. They were tested for four infections. About 18% had human papillomavirus. This infection can cause cervical cancer. Chlamydia affected 4%. About 2.5% had trichomoniasis, and 2% had herpes simplex virus. The Associated Press wrote about the study March 11.

Monthly personal counseling helped people keep off about half of the weight they lost for 2½ years, a study has found. A group that received Web-based counseling did almost as well, but results fell off by the end of the study. More than 1,000 people were in the study. They began with a six-month weight loss program. They lost an average of 18.7 pounds. Then they were randomly assigned to personal, Web-based or no counseling. After 2½ years, those who got personal counseling had kept off an average of 9.2 pounds. The average was 7.3 pounds for the Web program and 6.4 pounds for the other group. The study was published March 12 in the Journal of the American Medical Association.

Smokers who improve their diets may reduce their risk of stroke, a study suggests. Researchers kept track of 26,556 Finnish male smokers for more than 13 years. Some of the men ate an average of 589 milligrams of magnesium each day. These men had a 15% lower risk of strokes caused by a blockage of blood flow to the brain. Magnesium is found in whole grains, beans and some types of seafood and vegetables. Reuters Health news service reported on the study March 10. It was published in the journal Archives of Internal Medicine.

A new study looks at the increased risk for children if both parents have Alzheimer’s disease. The study included 111 Alzheimer’s couples. More than 2 in 10 of their adult children also developed the disease. The rate was about 3 in 10 for adult children over age 60. It was 4 in 10 for those over 70. On average, 6% to 13% of U.S. adults older than 65 have Alzheimer’s disease. The Associated Press wrote about the study March 11. It was in the journal Archives of Neurology.

A vaccine may help to reduce high blood pressure, a small study suggests. The new vaccine fights a body chemical called angiotensin II. This chemical tightens blood vessels and increases blood pressure. The study included 72 people with mild to moderate high blood pressure. They received 100 micrograms or 300 micrograms of the vaccine, or a placebo. The shots were repeated one month and three months later. The vaccine was found to be safe. Blood pressure fell in people who received the larger doses. The Guardian newspaper wrote about the study March 7. It was published in the journal Lancet.

A gene that affects how sensitive someone is to the drug warfarin can help determine the best starting dose, researchers say. Warfarin (Coumadin) is a blood thinner. It is used to prevent dangerous clots. But different people need very different doses. Researchers looked at two genes in 297 people who were starting to take warfarin. The VKORC1 gene affects sensitivity to the drug. CYP2C9 governs how fast the body removes the drug. Warfarin thinned the blood faster in people with a different version of VKORC1. CYP2C9 did not affect this early response. HealthDay News reported on the study March 5. It was published in the New England Journal of Medicine.

Increased heart risk among women who took hormones in a study faded in the three years after they quit, researchers say. The study of hormone use after menopause was halted in 2002. Women assigned to take hormones were told to quit because they showed a higher risk of heart disease and breast cancer than women who took fake pills. In the next two to three years, heart risk returned to normal, the new study found. But overall cancer risk was 24% higher than for women who took fake pills. The Associated Press wrote about the study March 5. It appeared in the Journal of the American Medical Association.