Here are some of the latest health and medical news developments, compiled by editors of HealthDay:

Scientists Announce 1st Map of Human Genetic Variations

U.S. scientists on Thursday announced that they'd created the first map of common human genetic variations, information that may help predict disease risk and provide improved treatment.

The map, which outlines common patterns of DNA differences between people, was created by Perlegen Sciences Inc. of California. It's viewed as a major advance in creating gene-based medicine, the Associated Press reported.

The research was published in the journal Science and presented at the American Association for the Advancement of Science. A more detailed version of the map of these genetic variations is expected to be unveiled later this year.

All humans share DNA that is 99.9 percent similar. Variations in the remaining DNA distinguish people from each other, influencing such things as eye and hair color and risks for various diseases.

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Vitamin D May Help Reduce Prostate Cancer Risk

A dose of sunshine may help men reduce their risk of prostate cancer, suggest findings from a U.S. study of nearly 15,000 men.

The study found that men with higher levels of vitamin D in their blood had half the risk of developing aggressive forms of prostate cancer than men with lower amounts of vitamin D in their blood, the Associated Press reported.

The body requires 15 minutes of sunshine a day to produce vitamin D, which can be also be obtained through food and supplements.

The findings from the Physicians' Health Study at Brigham and Women's Hospital and Harvard Medical School were presented Thursday at a cancer conference.

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Sen. Arlen Specter Has Hodgkin's Disease

Sen. Arlen Specter, a Pennsylvania Republican and chairman of the Senate Judiciary Committee, announced Wednesday that he has been diagnosed with Hodgkin's disease.

He's scheduled to undergo chemotherapy every two weeks for up to 32 weeks at the Abramson Cancer Center of the University of Pittsburgh, the Los Angeles Times reported.

Specter, 75, had medical tests Monday after experiencing persistent fevers and enlarged lymph nodes. A lymph node biopsy tested positive for Hodgkin's disease. A bone marrow biopsy indicated that the cancer has not spread.

Specter's oncologist said the senator had an excellent chance of being cured, according to a statement from Specter's office. It's expected he will be able to continue with all his duties while he's receiving treatment.

Hodgkin's disease, which is sometimes called Hodgkin's lymphoma, is a cancer that starts in lymphatic tissue. Lymphatic tissue includes the lymph nodes and related organs that are part of the body's immune and blood-forming systems, according to the American Cancer Society.

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Stress Protein Could Signal Heart Problems

A protein produced when the body is stressed could be a powerful predictor of clogged arteries that can lead to heart disease, Danish researchers report in Thursday's New England Journal of Medicine.

The protein, B-natriuretic peptide (BNP), is already used by some doctors to analyze possible congestive heart failure characterized by shortness of breath, the Associated Press reported. The Danish researchers studied the protein levels of more than 1,000 patients with clogged heart arteries, a condition that often causes chest pain known as angina.

People with the highest protein levels were more than twice as likely to die from any cause than those with the lowest levels, the AP reported.

The test typically costs less than $50, the wire service said.

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Too Few Children Get Hepatitis A Vaccine: Study

Many children at high risk of hepatitis A aren't being vaccinated for the disease as often as they receive other recommended shots, the U.S. Centers for Disease Control and Prevention reports from its first-ever national analysis.

Hepatitis A vaccination rates for children aged 24 months to 35 months varied widely from 6.4 percent to 72.7 percent in areas where routine vaccination is recommended, the agency reported Thursday in its Morbidity and Mortality Weekly Report. These numbers were lower than overall rates for other recommended pediatric vaccines, the CDC said.

Vaccination rates were highest among ethnic populations that traditionally have been at risk of the liver disease, including Hispanics, American Indians, and Alaskan native children, the agency said. But more children should be inoculated if hepatitis A rates are to continue their recent decline, the CDC said.

Good personal hygiene and proper sanitation can help prevent hepatitis A, which is normally transmitted via contact with contaminated feces, the agency said. Signs of the disease include jaundice, abdominal pain, fever, fatigue, loss of appetite, nausea, and diarrhea.

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Michael Jackson Leaves Hospital After Flu Spell

Pop singer Michael Jackson, on trial amid child molestation charges, was discharged Wednesday night from a Santa Maria, Calif., hospital where he had been treated for severe flu symptoms, CNN reported.

Jury selection in Jackson's trial was postponed for a week after he was taken to the emergency room on Tuesday. A spokesman said Jackson, 46, would continue his recovery at home.

Jackson was discharged not long after a Marian Medical Center doctor had told reporters the singer would stay in the hospital until at least Thursday, the network said. There was no immediate explanation for the discrepancy.