NEW YORK (Reuters Health) - Most US kids aren't getting enough vitamin D, a report in Pediatrics shows, raising their risk of weak bones and, possibly, heart disease.

While the new findings shouldn't spur parents to start mega-dosing their kids with the vitamin, most children could benefit from a little more sunshine, Dr. Michal L. Melamed of the Albert Einstein College of Medicine in the Bronx, New York, told Reuters Health. And giving children a multivitamin containing 400 international units (IUs) of vitamin D is a good idea too, she added, especially in the winter months.

A few small studies have suggested that vitamin D deficiency may be widespread among US children, Melamed and her team note in their report. To get a sense of how common the problem is nationwide, they looked at data on 6,275 children and young adults one to 21 years old from the 2001-2004 National Health and Nutritional Examination Survey.

Nine percent were classified as "deficient" in vitamin D, meaning the concentration of the nutrient in their blood was below 15 nanograms per milliliter (ng/mL), while 61% were vitamin D "insufficient," with levels between 15 and 29 ng/mL.

Deficiency was more common in older children, girls, obese individuals, those who drank milk less than once a week and those who spent more than four hours a day in front of a TV, computer or video screen. Non-Hispanic black children and Mexican-Americans also were more likely than whites to be deficient in vitamin D.

The researchers also found that kids with vitamin D deficiency were more likely to have high blood pressure, low calcium levels (important for bone growth), and low levels of "good" HDL cholesterol than children with adequate amounts of the vitamin.

If vitamin D deficiency does turn out to increase heart disease risk, as the cholesterol and blood pressure figures suggest, "this could have long-term consequences for the health of Americans," Melamed said.

Parents can help their children get enough vitamin D by making sure they spend at least 15 to 20 minutes in the sun without sunscreen, Melamed said. But the ability of the skin to produce vitamin D from sun-as well as the risk of skin cancer--varies depending on skin color, she added. Dark-skinned children may need an hour or more outdoors without sunscreen, while it might be best for very fair kids with a family history of melanoma not to spend any time outdoors without sun protection, according to the researcher.

"There are definitely worries about getting too much sun, and what we're advocating is not sunbathing," Melamed said.

And vitamin D supplements must be used cautiously as well, she added. "Taking too much can lead to kidney stones and other kidney problems," Melamed said. "Taking more than 400 IU a day, which is the current recommendation, may not be safe."

But it's OK to take 400 IU a day, the amount commonly contained in multivitamins, and especially important to do so in the wintertime, when people get less sun and vitamin D levels drop, she added. In Melamed's study, just 1 in 25 of the study participants had taken 400 IU of vitamin D daily for the past month.

Other research has shown vitamin D deficiency among US teens climbed sharply between 1988 and 1994, Melamed noted. "Definitely in the last 20 years there's been an increase in vitamin D deficiency."

One factor is likely more scrupulous use of sunscreen, she said. "There's also been less milk drinking, less outdoor activities, more indoor activities, watching TV and playing computer games," she added. "All of these things have kind of contributed to what we're seeing."

SOURCE: Pediatrics, online August 3, 2009.

Copyright © 2009 Reuters Limited.

NEW YORK (Reuters Health) - Women who quickly put on pounds after starting birth-control injections seem to be at risk of significant long-term weight gain, a new study suggests.

The findings, say researchers, should help clarify which women are likely to see unhealthy weight changes with the contraceptive, called depot medroxyprogesterone (DMPA) -- better known by the brand-name Depo Provera.

DMPA is given by injection about once every three months, making it a relatively convenient and low-cost form of birth control, according to the authors.

But the current study found that women who rapidly put on weight soon after starting DMPA -- gaining more than 5 percent of their initial weight within 6 months -- were at risk of continuing that trend over the long term.

About one-quarter of the women in the study were "early gainers." And on average, they put on roughly 22 pounds over three years, the researchers report in the journal Obstetrics & Gynecology.

That compared with about 5.5 pounds among women who had gained less than 5 percent of their initial body weight in their first six months on DMPA.

The findings suggest that women who quickly gain weight with the contraceptive should talk with their doctors about other options for birth control, advised Dr. Abbey Berenson, the senior researcher on the study and a professor of obstetrics and gynecology at the University of Texas Medical Branch at Galveston.

Such early gainers, she told Reuters Health, appear likely to continue on that path.

The study, which followed 195 white, black and Hispanic women on DMPA, also identified certain risk factors for rapid weight gain. Women who were not obese to begin with, as well as those who had already had children, were at relatively higher risk of becoming an early gainer.

Of the 135 women who were not obese at the outset, 45 became early gainers, versus only six of 60 women who were obese to begin with. And of 117 women who'd had children, 37 became early gainers, compared with 14 of 78 women with no children.

Rapid weight gain was also seen more often in women who reported an increased appetite soon after starting on the contraceptive.

But whether appetite changes explain the excessive weight gain in some women is unknown. Berenson and her colleagues found no association between study participants' calorie intakes and their long-term weight gain.

Other potential reasons, the researchers note, include the effects of DMPA on certain hormones involved in metabolism.

SOURCE: Obstetrics & Gynecology, August 2009.

Copyright © 2009 Reuters Limited.

NEW YORK (Reuters Health) - Men may not want to pin their hopes on acupuncture as a treatment for impotence, or erectile dysfunction, a new review of evidence suggests.

Acupuncture is an ancient Chinese method of stimulating specific body points through the insertion of specialized pins that sometimes carry faint electrical charges. Traditionally, acupuncture has been used to maintain and restore body functions.

Several studies had reported "acupuncture increases nitric oxide," which has been tied to the ability to maintain erections, Dr. Myeong Soo Lee, at Korea Institute of Oriental Medicine in Daejeon, told Reuters Health by email.

Yet to date, published studies that evaluated acupuncture as a treatment for erectile dysfunction provide "no convincing evidence" that acupuncture is beneficial for this condition, Lee and colleagues report in the journal BJU International.

After assessing 80 research studies, Lee's team found only 2 that were randomized controlled trials - that is, studies that compared a treatment group with group that did not receive treatment or underwent a sham treatment. This trial design is the gold standard for research studies. (The acupuncture treatment was applied all over the body, not on the penis itself.)

One of those two trials reported benefits, while the other did not, the authors note.

Lee's group also identified 2 trials, in a total of 45 men, that did not include a group of men that did not receive treatment or underwent a sham treatment.

Those trials both suggested some benefit from acupuncture among men with erectile dysfunction, but the investigators caution that the design leaves studies open to bias and often suggest false-positive results.

Taken together, these results fail to show whether acupuncture offers any benefit as a treatment for erectile dysfunction. "More rigorous trials are required," Lee said.

SOURCE: BJU International, August 2009.

Copyright © 2009 Reuters Limited.

NEW YORK (Reuters Health) - A contact lens that gradually dispenses a steady stream of medication to the eye could ease treatment for glaucoma and other eye ailments if it advances through animal and human testing, according to new research.

For people who need eye drops for conditions such as glaucoma -- damage to the nerve that connects the eye to the brain -- using them several times a day is burdensome and inefficient. Due to natural blinking and tearing, typically only a little bit of the medication is absorbed by the eye. The drug-dispensing contact lens may boost convenience and effectiveness, say authors of the study.

Laboratory tests show that the drug-dispensing contact lens "can release really large amounts of drug for very long periods of time at a very steady rate," Dr. Daniel Kohane, director of the Laboratory for Biomaterials and Drug Delivery at Children's Hospital Boston, noted in a telephone interview with Reuters Health.

Kohane collaborated with Dr. Joseph Ciolino of the Massachusetts Eye and Ear Infirmary and colleagues at the Department of Chemical Engineering at the Massachusetts Institute of Technology to develop the drug-dispensing contact lens.

Although other groups have developed drug-releasing contact lenses, none have been able to achieve a constant, steady stream of medication at high enough levels to be therapeutic, the researchers note in the journal Investigative Ophthalmology and Visual Science. Prior contact lenses "have released very small amounts of drug for long periods of time or a lot of drug for not a long time," Kohane said.

In the lab tests, contact lens Kohane's team developed dispensed appropriate levels of ciprofloxacin -- an antibiotic used in eye drops -- for 30 days and in some tests for as long as 100 days. "We're talking really large levels of the drug, for example, enough antibiotic to still be effective for that long," Kohane said.

The drug-dispensing contact lenses are the size and thickness of commercially available contact lenses. The researchers have begun testing them in animals and hope to begin human testing soon.

Drug-dispensing contact lenses "could be used with almost any drug that could be applied to the eye, particularly the front of the eye, and for a range of conditions such as glaucoma, allergic conjunctivitis, dry eye, infections, pain, and things like that," Kohane noted.

SOURCE: Investigative Ophthalmology and Visual Science, July 2009.

Copyright © 2009 Reuters Limited.

WASHINGTON (Reuters) - Malaria may have jumped to humans from chimpanzees much as AIDS did, U.S. researchers reported on Monday in a study they hope could help in developing a vaccine against the infection.

They found evidence the parasite that causes most cases of malaria is a close genetic relative of a parasite found in chimpanzees. Genetic analysis suggests the human parasite is a direct descendant of the chimp parasite, they reported in the Proceedings of the National Academy of Sciences.

The malaria-causing parasite Plasmodium falciparum may have been transmitted to human beings as recently as 10,000 years ago, Francisco Ayala of the University of California Irvine and colleagues said.

"When malaria transferred to humans, it became very severe very quickly," Ayala said in a statement.

"The disease in humans has become resistant to many drugs. It's my hope that our discovery will bring us closer to making a vaccine."

Malaria kills an estimated 1 million people a year, mostly children, according to the World Health Organization. The mosquito-borne parasite causes severe disease in more than 300 million every year.

Ayala's team sampled blood samples from 94 chimpanzees in Cameroon and Ivory Coast to find the apes' version of the parasite.

"The closest known relative of P. falciparum is a chimpanzee parasite, Plasmodium reichenowi," they wrote. They found eight samples of P. reichenowi.

Their genetic testing of the samples showed all known P. falciparum parasites originated from P. reichenowi.

Researchers are trying to make a vaccine against malaria but are having difficulty. Understanding how it became adapted to humans could help in this work.

The finding is the latest to show that some of humanity's worst diseases originated in animals. AIDS came from chimpanzees -- and French researchers reported on Sunday that they found a Cameroonian woman had been infected with an HIV virus that apparently came from gorillas.

Swine flu, H5N1 avian influenza and in fact all influenza viruses are believed to have originated in animals. Other animal-to-human infections include severe acute respiratory syndrome, or SARS, which killed 800 people in 2003-2004, Ebola and Marburg viruses, and plague.

SOURCE: Proceedings of the National Academy of Sciences, advance online publication, August 3, 2009.

Copyright © 2009 Reuters Limited.