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

Up to Half of Americans Have Pre-Existing Illness: Report

A U.S. government analysis released Tuesday suggests that as many as 129 million Americans under age 65 have pre-existing health conditions that could result in them being rejected by private insurers or having to pay more for health coverage.

The ailments that affect one-fifth to one-half of non-elderly Americans range from cancer to chronic conditions such as high blood pressure, heart disease and asthma, the Washington Post reported.

The analysis was released by the secretary of the department of Health and Human Services just hours before an expected House vote on a bill to repeal the new health care law. Republicans dismissed the document as "public relations" by the Obama administration.

While it can be difficult for sick people to buy insurance, the analysis overstates the problem, an insurance industry spokesman told the Post.

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Cheney Thinking About Heart Transplant

Given his medical history, former U.S. Vice President Dick Cheney says he'll need to make a decision about whether to have a heart transplant.

He currently requires a battery-powered heart pump, which makes it "awkward to walk around," Cheney told NBC in an interview, the Associated Press reported.

"I'll have to make a decision at some point whether I want to go for a transplant," he said in the interview.

Cheney, 69, has had five heart attacks since the age of 37. His most recent was last year, the AP reported. He had bypass surgery in 1988 and two subsequent angioplasties to open narrowed coronary arteries. He had a pacemaker implanted in his chest in 2001 and in 2008 required an electric shock to restore normal rhythm to his heart.

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Fatty Acids Ease PMS Symptoms: Study

Dietary supplements that contain essential fatty acids can help ease symptoms of premenstrual syndrome, according to a new study.

Brazilian researchers found that PMS symptoms were significantly reduced when women took capsules with about one gram of a blend of three essential fatty acids, CNN reported.

The study appears in the current issue of the journal Reproductive Health.

The human body does not produce essential fatty acids, which are found in foods such as eggs, nuts, vegetable oils, fish and supplements, CNN reported.

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Apple CEO Steve Jobs Takes Medical Leave

Apple Inc. CEO Steve Jobs is taking his second medical leave of absence in two years in order to focus on his health.

He announced his intentions in a note Monday to company employees, but no further information was provided about his current condition, the Associated Press reported.

In 2004, Jobs was treated for a rare form of pancreatic cancer and in 2009 he had a liver transplant.

Jobs said he will continue as CEO during his medical leave and will be involved in major decisions, but the company's chief operating officer will be responsible for day-to-day operations, the AP reported.

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Opposition to Health Care Law Decreases: Poll

The level of opposition to the U.S. health care law has decreased, according to a phone survey of 1,001 adults conducted Jan. 5-10.

The Associated Press-GfK poll found that 41 percent of respondents oppose the law, while 40 percent support it. Following November's congressional elections, opposition was 47 percent and support was 38 percent.

Opposition remains strongest among Republicans, with 71 percent against it, while 35 percent of independents and 19 percent of Democrats are oppose the law.

Overall, strong opposition to the law is 30 percent, which is close to the lowest level recorded in AP-GfK polls going back to September 2009.

Only about one in four respondents want the law repealed, 43 percent want it changed so that it does more to rework the health care system, and fewer than one in five want it left as it is, the AP reported.

Nearly six in 10 respondents are against the law's requirement that people must have health insurance or face penalties.

A Republican-led vote on repealing the health care law is expected to take place this week in the House.

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