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HEALTHSCAN
The smart side
Silicone hydrogel lenses can be worn for longer hours
PEOPLE WITH high levels of cholesterol do better on a variety of tests measuring mental ability, researchers from Boston University have found. The study was led by Dr. Penelope K. Elias.
The findings grow out of information compiled by the long-term Framingham Heart Study, and are based on the medical histories of 789 men and 1,105 women over 18 years.
Although high cholesterol increases the risk of serious illness, including heart disease, the researchers found that when it comes to the brain, it may be a slightly different matter.
When the volunteers were given tests to measure mental skills like memory, concentration, abstract reasoning and organisation, those with cholesterol levels that were borderline-high or greater (200 and above) scored somewhat better.
The researchers were able to look only at the total cholesterol levels, and so could not tell whether the so-called bad and good cholesterol had different effects, Dr. Merrill F. Elias, one of the authors, said.
The researchers said the link appeared clear, but expressed concern that people might make the mistake of ignoring high cholesterol or going off medication for it.
Almost none of the participants in the study was taking cholesterol drugs, and no one knows whether someone whose cholesterol had been lowered medically would have weaker skills.
And, in any case, Merrill Elias said, the trade-off is not worth it.
"Do you want to be a very intelligent person when you're talking to the person who's putting a stent in you because you have heart disease?" he asked.
Attack time
FOR MOST people, the hours just after rising, from 6 a.m. to noon, are the most likely times for heart attacks, while the sleeping hours are the safest.
But for the millions of people who have obstructive sleep apnoea, a breathing disorder, heart attacks are much more likely in the sleeping hours, a new study finds.
Researchers from the Mayo Clinic say that for reasons that are unclear, people with the disorder are much more likely to have heart attacks from 10 p.m. to 6 a.m.
The study was led by Dr. Apoor S. Gami.
For people who have sleep apnoea, the likelihood of heart attacks' occurring in the sleeping hours makes sense, given the tremendous stresses the disorder places on the body, said Dr. Virend K. Somers, a co-author of the study.
People with sleep apnoea may be wrenched awake hundreds of times a night — often without their knowledge — when their airways collapse and they stop breathing.
Although the disorder has not been proved to increase the risk of heart attacks, it is suspected of doing so, and it has been linked to high blood pressure. Somers said he believed that effective treatment for sleep apnoea would reduce that patient's risk for a heart attack.
The problem, he said, is that so many people do not realise they have the disorder. (Snoring is often a symptom.) "The vast majority of sleep apnics are still not diagnosed or treated," he said.
Lens lesson
IT IS widely known that people who sleep wearing contact lenses are taking a risk that they could end up with a serious infection.
But a newer generation of contact lenses has a much lower risk, a new study finds, and researchers studying them suggest that people who insist on wearing contacts in their sleep should use them. The study was led by Dr. Philip B. Morgan of the University of Manchester in England.
The researchers said that among people using extended-wear contact lenses made from silicone hydrogel, the risk of serious infection was only about a fifth as great as it was for people wearing lenses made from just hydrogel.
The researchers arrived at their findings after spending a year surveying patients who came into a Manchester hospital for eye treatment. The patients were asked about their contact lens use, including what kind they wore and whether they ever slept in them. Morgan said that his research was supported by the contact lens industry but the study looked only at generic contact lenses, not those with brand names.
The doctors examined patients' corneas for injury and infection, comparing the severity of injury with patients' lens-wearing habits.
While the patients who slept in silicone hydrogel lenses unquestionably did better than those who slept in other lenses, the findings were hardly an endorsement for leaving lenses in at night. The study found a significantly higher incidence of serious infection among all people who wore contacts while they slept, compared with those who used them only in waking hours.
The main difference between silicone hydrogel lenses and others, the study noted, is that they are more adept at letting oxygen pass through. So the findings lend support to a theory that if the cornea is deprived of enough oxygen, it can develop an infection.
Though disposable contact lenses are becoming increasingly popular, the study did not find them any safer in terms of infection.
(Courtesy: New York Times)
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