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Taking folic acid supplements doesn’t appear to prevent colon polyps from coming back, new research shows, although it may be helpful for people who have low levels of the B vitamin in their blood.

These polyps, or adenomas, can develop into cancer if they are not detected and removed. While there’s evidence that folate, the natural form of this nutrient, might help protect people from developing colon cancer, studies looking at whether folic acid supplements can ward off adenoma recurrence have had mixed results.

In fact, according to Dr. Kana Wu of the Harvard School of Public Health and colleagues, one study actually found that people who took folic acid supplements were more likely to have recurrent adenomas than people given placebo.

To investigate further, Wu and colleagues assigned nearly 700 men and women participating in the Health Professionals Follow-Up Study and the Nurses’ Health Study, two large ongoing studies, to take 1 milligram of folic acid daily or a placebo. All of them had previously been diagnosed with colon polyps.

During follow-up, which lasted for up to six-and-a-half years, 72 people in the placebo group developed recurrent polyps, while 62 in the folic acid group did. This wasn’t a statistically significant difference.

However, for people with low concentrations of folate in their blood at the study’s outset, taking folic acid reduced recurrent adenoma risk by about 40 percent. The protective effect was particularly strong among people who consumed more alcohol; alcohol is known to deplete a person’s folate levels.

This suggests, the researchers conclude, that folic acid supplementation “may be beneficial” among people with low vitamin B levels who drink a lot of alcohol.

Right now, Wu noted in an email to Reuters Health, the Institute of Medicine says adults should consume no more than 1 milligram of folate daily.

While folic acid supplements are recommended for pregnant women, as well as people with folate deficiency and those taking drugs that interfere with folate metabolism, Wu added, “more research is needed to establish what effect taking additional high dose folic acid supplements would have on healthy adults with regard to preventing certain diseases or whether it may even be harmful.”

Kidney transplant patients with sleep apnea are at increased risk for high blood pressure, heart disease and stroke, Hungarian researchers say.

The study of 100 kidney transplant recipients found that 25 percent had moderate to severe sleep apnea, a rate similar to that seen in kidney disease patients on dialysis awaiting a transplant. This means that both types of patients who have the breathing-related sleep disorder should be considered at high risk for serious heart-related complications, the study authors noted.

Transplant recipients with sleep apnea were more than twice as likely as those without the syndrome to be taking three or more anti-hypertensive drugs, but still had higher blood pressure than those without the sleep disorder. Obesity increased a transplant patient’s risk of developing sleep apnea.

When the researchers calculated risk scores, they found that kidney disease patients with sleep apnea were twice as likely to suffer heart disease or stroke than those without sleep apnea.

“We propose that sleep apnea is a new risk factor for hypertension and cardiovascular events in kidney-transplanted patients,” said Dr. Miklos Zsolt Molnar, of Semmelweis University in Budapest, in a news release from the American Society of Nephrology.

“Physicians should screen transplant patients for obstructive sleep apnea and offer appropriate treatment,” the study authors concluded.

Extreme temperatures and heavy air pollution boost heart attack risk, according to a major new study.

And on days when the air is extra dirty and the temperature is unusually hot or cold, the effects are likely to be particularly bad, given that temperature and pollution seem to harm the body in different ways, Dr. Krishnan Bhaskaran of the London School of Hygiene and Tropical Medicine in the UK, the lead author of the research, told Reuters Health.

Several studies have linked changes in temperature to increases in deaths due to any cause, as well as heart disease mortality, Bhaskaran and his team note in their reports. But looking at heart attacks-not just deaths from heart disease-could offer a more accurate picture of the overall health risks of temperature changes and air pollution, they say, and might also offer clues to why they may trigger heart attack in high-risk people.

In two separate reports, the researchers reviewed 19 studies on temperature and heart attack and 26 examining air pollution and heart attack.

In the 12 temperature studies that collected winter data, eight showed short-term increases in heart attack risk with colder temperatures. Seven of the 13 studies that looked at the effects of warmer temperatures found increased heart attack risk in hotter weather.

Cold temperatures seemed to have a greater effect on heart attack risk in areas that were warmer, on average, Bhaskaran and colleagues note, suggesting that people living in colder areas may be better adapted to dips in temperature. But hot days boosted heart attack risk whether they happened in Sweden or Brazil.

In a city that normally sees 10 heart attacks a day, Bhaskaran explained, the findings show there might be an extra one to four heart attacks on the hottest or coldest days.

“There was a lot of variation in the methods and quality of the studies we reviewed, so more work is needed in this area, but we thought the results were consistent enough to suggest that these effects are real,” he added.

The evidence from the pollution studies was less clear-cut, the researcher said, but overall suggested that the risk of heart attack increases with levels of several different pollutants. Also, he noted, there appeared to be no “safe” level of air pollution at which no effect on heart attack risk was seen.

“Our findings would suggest that further lowering limits would likely further reduce the health burden associated with pollution, which is of course a desirable outcome,” he said.

Governments can also make an effort to alert at-risk people when extreme temperatures or high levels of pollution are expected, the researcher said. He noted that the UK now makes automated phone calls to people with emphysema when they are at risk due to changes in temperature; this, he said, has led to a reduction in hospital admissions for lung disease patients.

In an editorial accompanying the study, Professor David E. Newby of the University of Edinburgh and colleagues note that efforts to control air pollution are likely to help reduce carbon dioxide emissions as well, possibly helping to alleviate the effects of climate change down the road.

The self-reported health of the newly retired improves so much that most feel eight years younger, a new European study suggests.

This happy news was true of most everyone except a small minority — only 2 percent — who had experienced “ideal” conditions in their working life, anyway.

“The results really say three things: That work puts an extra burden on the health of older workers, that the effects of this extra burden are largely relieved by retirement and, finally, that both the extra burden and the relief are larger when working conditions are poor,” said Hugo Westerlund, lead author of a study published online Nov. 9 in The Lancet. “This indicates that there is a need to provide opportunities for older workers to decrease the demands in their work out of concern for their health and well-being.”

But of course, added Westerlund, who is head of epidemiology at the Stress Research Institute at Stockholm University in Sweden, “not all older workers suffer from poor perceived health. Many are indeed eminently healthy and fit for work. But sooner or later, everyone has to slow down because of old age catching up.”

Last week, the same group of researchers reported that workers slept better after retirement than before. “Sleep improves at retirement, which suggests that sleeping could be a mediator between work and perception of poor health,” Westerlund said.

This study looked at what the same 15,000 French workers, most of them men, had to say about their own health up to seven years pre-retirement and up to seven years post-retirement.

As participants got closer to retirement age, their perception of their own health declined, but went up again during the first year of retirement.

Those who reported being in poorer health declined from 19.2 percent in the year prior to retirement to 14.3 percent by the end of the first year after retiring. According to the researchers, that means post-retirement levels of poor health fell to levels last seen eight years previously.

The changes were seen in both men and women, across different occupations, and lasted through the first seven years of not punching the clock.

Workers who felt worse before retirement and had lower working conditions reported greater improvements as soon as they retired, the team found.

“Those who had low job satisfaction — a lot of burden for little satisfaction — those were the ones complaining of their health,” said Dr. Gary Kennedy, director of geriatric psychiatry at Montefiore Medical Center in New York City. “People with more authority or better education, a better sense of control over what they were doing and less demand were much less likely to complain,” he added.

“That’s not really surprising,” he said. “An old study of English civil-service workers in Britain found that those who felt they had a lot of responsibility but little control over their workplace were more likely to develop heart disease,” he added. “You can work hard but if you feel like you’re not at the mercy of a job, you still have the illusion of control. That’s an important illusion to maintain.”

A major question is whether these European findings apply to conditions in the United States.

“It’s a little bit difficult to apply directly to our workforce but … we can draw some conclusions about keeping a strong and healthy workforce through the life span,” said Angie Hochhalter, assistant professor of internal medicine at Texas A&M Health Science Center College of Medicine and research scientist in geriatrics at Scott & White in Temple, Texas.

“We know that we need strong health care but also mental services because, in [the study], those people with depression really saw a dramatic change after retirement,” she explained.

“In addition to strong systems, there’s also some degree of personal responsibility for trying to keep ourselves healthy — managing stress from work and from home, healthy eating and physical activity, and staying involved with social support,” Hochhalter added.

Workers in both the United States and Europe are likely to be affected similarly by poor working conditions, Westerlund added.

Babies who are deprived of oxygen at birth often go on to have lifetime disabilities, but research has shown that cooling infants can help prevent problems.

Now, a new study reports that the cooling actually reduces the number of brain lesions in the babies.

Oxygen starvation at birth can cause a condition called hypoxic-ischemic encephalopathy, which can be fatal. Oxygen starvation also accounts for about 20 percent of cerebral palsy cases.

An earlier study found that chilling infants who suffer from oxygen deprivation can help reduce rates of cerebral palsy and improve their motor skills later in life. In the new study, reported online Nov. 5 and in the January issue of The Lancet Neurology, researchers investigated whether MRI scans would reveal fewer cerebral lesions in infants who were cooled.

That turned out to be the case. After reviewing MRI brain scans of 131 infants, they found 30 to 40 percent fewer lesions in areas of the brain where neurological development occurs. The infants who underwent cooling were three times more likely than those who didn’t to have normal scans.

The scans also allowed doctors to predict with more than an 80 percent degree of certainty whether the infants would die or be disabled by the time they were 18 months old. The accuracy rate was 84 percent for the infants who were cooled and 81 percent for those who were not.

Taking a popular type of antidepressant during pregnancy may increase the risk for preterm birth, the need for treatment in a neonatal intensive care unit and lower overall health for the baby, according to a new study.

Researchers compared birth outcomes among babies born to 329 women who took selective serotonin reuptake inhibitors (SSRIs) during pregnancy, 4,902 women who had a history of psychiatric illness but did not take SSRIs during pregnancy and 51,770 women with no history of mental illness.

Compared with women who had no history of mental illness, those who took SSRIs during pregnancy gave birth an average of five days earlier and had double the risk for preterm delivery. Babies of mothers who took SSRIs during pregnancy were significantly more likely than infants in the other two groups to have a five-minute Apgar score of seven or lower (seven is the general indicator of good infant health) or to be admitted to the neonatal intensive care unit. Exposure to SSRIs did not affect birth weight or head circumference.

The researchers also found that SSRI-exposed infants admitted to the neonatal intensive care unit had symptoms including seizures, jitteriness, infections, respiratory problems and jaundice that may have been caused by withdrawal from SSRIs or adverse effects from them.

The findings appear in the October issue of Archives of Pediatrics & Adolescent Medicine.

“The study justifies increased awareness to the possible effects of intrauterine exposure to antidepressants,” the researchers concluded. “However, treatment of depression during pregnancy may be warranted, and future studies need to distinguish between individual SSRIs to find the safest medication.”

It’s estimated that more than 10 percent of pregnant women have depression. The authors noted that SSRIs have been shown to cross the placenta and be present in the umbilical cord blood of infants whose mothers took the drugs during pregnancy.

Although new research links mercury in seafood with high blood pressure, this isn’t reason enough for most people to stop eating fish, the study leader says.

“The small increase of blood pressure due to methylmercury will never outweigh the benefits of omega-3 fatty acids,” said Dr. Eric Dewailly, a professor in the department of social and preventive medicine at Laval University in Quebec and lead author of a report in the Oct. 5 issue of Hypertension.

Diets rich in omega-3 fatty acids from oily fish, such as fatty sardines, herring, trout and salmon, are associated in many studies with a reduced risk of death from heart attack, stroke and other cardiovascular disease. The American Heart Association recommends eating two meals a week containing four to six ounces of such fish.

But because fish can contain high levels of methylmercury, which can interfere with the normal development of the nervous system and brain in fetuses and newborns, the U.S. Food and Drug Administration advises pregnant women, those trying to get pregnant, nursing women and children to limit their fish intake.

FDA guidelines limit intake of low-mercury fish for those individuals to 12 ounces a week and high-mercury fish to three 6-ounce servings a month. The FDA also advises avoiding fish most like to carry the highest levels of mercury — shark, swordfish, king mackerel and tilefish.

At first glance, the Canadian study appears to add high blood pressure to the list of problems linked to methylmercury in fish. Dewailly and his colleagues conducted a survey of Inuit residents of 14 Nunavik communities in northern Quebec, where the traditional diet is based on fish and marine mammals.

It found an average blood mercury level of 50 nanomoles per liter of blood, much higher than the 4-nanomole level of the general U.S. population. It also found a relationship between blood mercury levels and blood pressure after adjusting for other factors, such as smoking and physical activity.

Studies have shown that exposure to environmental mercury can affect the endothelium, the delicate lining of blood vessels, and decrease the ability of smooth muscles to relax, which could explain the slight increase in blood pressure seen in the study, Dewailly said.

It was not a great effect, he said. “For every 10 percent increase in blood mercury level, there is a 0.2 millimeter increase in blood pressure,” Dewailly said. “Even if you apply that to an entire population, that is a small effect.”

So, a 10 percent increase in blood mercury would raise a blood pressure reading from 120/80 to 120.2/80, Dewailly indicated. That is not a reason to avoid fish “if you look at the fish nutrients that are reported to be associated with so many benefits,” he said.

But it’s important to eat the right kind of fish, the oily species, Dewailly said. Anyone worried about blood pressure should avoid fish that have low levels of omega-3 fatty acids and high mercury content, such as big predator fish, including swordfish, marlin and shark, he said.

Another heart expert concurred.

“Many Americans can safely enjoy eating fish as a regular part of their diet to achieve the health benefits of omega-3 fatty acids,” said Penny Kris-Etherton, distinguished professor of nutrition at Pennsylvania State University and a member of the American Heart Association Council on Nutrition Metabolism and Physical Activity Committee.

“And this includes canned light tuna, which is significantly lower in mercury than white tuna,” she said in a statement.

Three Americans won the Nobel prize for medicine on Monday for revealing the existence and nature of telomerase, an enzyme that helps prevent the fraying of chromosomes that underlies aging and cancer.

Australian-born Elizabeth Blackburn, British-born Jack Szostak and Carol Greider won the prize of 10 million Swedish crowns ($1.42 million), Sweden’s Karolinska Institute said.

“The discoveries … have added a new dimension to our understanding of the cell, shed light on disease mechanisms, and stimulated the development of potential new therapies,” it said.

The trio’s work laid the foundation for understanding how telomerase and telomeres — the small caps on the end of chromosomes that carry the DNA — affect cancer and age-related conditions.

Work on the enzyme has become a hot area of drug research, particularly in cancer, as it is thought to play a key role in allowing tumor cells to reproduce out of control.

One example, a so-called therapeutic vaccine that targets telomerase, in trials since last year by drug and biotech firms Merck and Geron, could yield a treatment for patients with tumors including lung and prostate cancer.

“Their research on chromosomes helped lay the foundations of future work on cancer, stem cells and even human aging, areas that continue to be of huge importance,” said Sir Leszek Borysiewicz, chief executive of Britain’s Medical Research Council.

“FOLLOW YOUR NOSE”

Blackburn, a molecular biologist and biochemist at the University of California San Francisco known for her work on DNA and cell division, said she had not stayed awake waiting for a call from the Nobel Prize Committee, even though her name topped many Nobel prediction lists.

“I was surprised. It is always a surprise when something like this happens,” she told Reuters in a telephone interview. “I was woken up and (it) took me a while to take it in.”

She said she had been in southern California the previous day for her mother-in-law’s 95th birthday. “The phone rang and I sort of groped around in the dark for it,” she said.

An outspoken researcher, Blackburn was fired in 2004 from President George W. Bush’s Council on Bioethics in what many scientists believed was her criticism of his policy on human embryonic stem cell research.

She said she knew that something like telomerase must exist from working with Szostak on telomeres, which help keep the ends of chromosomes together.

“Carol and I hunted it down,” she said. “We didn’t stumble over it. The molecular behavior of the ends of the chromosomes was screaming out that there was something going on, some hitherto unknown enzyme.”

Greider, 48, who grew up in Davis, California, where her father was a physicist, said winning the Nobel prize was especially significant because it recognized the value of discoveries driven by pure curiosity.

“We had no idea when we started this work that telomerase would be involved in cancer, but were simply curious about how chromosomes stayed intact,” she said in a statement.

“Our approach shows that while you can do research that tries to answer specific questions about a disease, you can also just follow your nose.”

PAYING FOR COLLEGE

Greider, now at the Johns Hopkins School of Medicine in Baltimore, started research on telomerase in the late 1970s with Blackburn, her academic adviser.

Szostak, 56, also said he started on the work without knowing what if any practical benefit it would bring. “Eventually its role in aging and cancer emerged from the work,” he said.

Asked what he planned to do with the prize money, Szostak said he would be putting his children through college.

Dr. Jeremy Berg of the U.S. National Institute of General Medical Sciences, which funded some of the research, said this year’s prize was not a surprise.

“It was at the top of all lists this year,” Berg said in a telephone interview.

Berg said Szostak, who works at Harvard Medical School in Boston, Massachusetts General Hospital and the Howard Hughes Medical Institute, had moved along since his work on telomerase.

“He is trying to figure out how he can make proto-cells and get them to copy their genetic material. That’s almost literally creating life in a test tube.”

All three new Nobel laureates were among those considered likely winners in a Thomson Reuters forecast.

Medicine is traditionally the first of the Nobel prizes awarded each year. The prizes for achievement in science, literature and peace were first awarded in 1901 accordance with the will of dynamite inventor and businessman Alfred Nobel.