DENTISTS often warn patients that inadequate toothbrushing and flossing habits could lead to gum disease and tooth loss. Now a study by Harvard University researchers suggests that losing your teeth also might heighten your risk of suffering a stroke.
The new study has found that men with fewer than 25 teeth had a 57% higher risk of suffering an ischaemic stroke than those who had 25 or more teeth. Ischaemic strokes are caused by blockage of an artery to the brain.
Scientists haven’t yet established a direct cause-and-effect between periodontal disease and cardiovascular disease. But the latest findings add to a growing body of research linking infections, including those of the mouth, to heart disease.
Scientists have proposed several explanations. Some believe that when bacteria in the mouth get into the bloodstream, they create inflammation that increases the build-up of plaque in the arteries. Plaque can break off and lodge in the heart, causing a heart attack, or in the brain, causing a stroke. Some believe a periodontal infection makes blood more likely to clot, raising the risk of stroke or heart attack. Another idea is that the bacteria might release a toxin that damages cells lining the arteries.
Previous studies of the link between gum disease and cardiovascular disease have been mixed. One found that stroke patients were more likely to have oral infections than healthy patients, and another found that people with periodontal disease were more likely to have thickened carotid arteries in the neck.
Researchers from the Harvard School of Dental Medicine published their findings in recent online issue of Stroke: Journal of the American Heart Association. The 12-year study followed 41,380 men, mostly white dentists, veterinarians, pharmacists, optometrists, osteopaths and podiatrists. All were 40 to 75 years old and had no heart disease or diabetes when they signed up.
There were 349 ischaemic strokes among the men. Patients with 17 to 24 teeth had a 50% higher risk of stroke than those with 25 to 32 teeth (a full set is 32). Those with 11 to 16 teeth had a 74% higher risk; those with 10 or fewer teeth had a 66% higher risk. Stroke risk was most closely related to the number of missing teeth when a man entered the study, not the number lost in the subsequent years.
“If infection is a major factor,” said Dr Don Smith, director of the stroke programme at Colorado Neurological Institute, “then good dental hygiene may achieve the level of importance in stroke prevention that we now accord to control of blood pressure, cessation of smoking, exercise and healthy diet.”
Mind over indegestion
HYPNOSIS has been so effective in treating irritable bowel syndrome that British researchers recently tested its usefulness for chronic indigestion.
More than 100 people at the Wythenshawe Hospital in Manchester, England, were assigned to receive 12 30-minute sessions of either hypnotherapy, supportive therapy and a placebo medication, or medication (rantidine twice a day) over 16 weeks.
In the short term, hypnotherapy had a slight edge over the other treatments: Symptoms improved 59% on average, compared with a 49% improvement in both the supportive therapy and drug treatment group.
But a year later, symptoms had not only improved 73% on average, compared with 34% with supportive therapy and 43% with medication, but none of those who had gone through the hypnosis programme were taking medication to control symptoms. Meanwhile, 82% of patients in the supportive group had to begin other treatment.
Although physicians are not certain how hypnotherapy works on the gastrointestinal tract, evidence that it is effective is “cumulative and consistent”, says an editorial accompanying the study in the December issue of Gastroenterology.
Window of fertility
WOMEN who are trying to become pregnant may not be using the most accurate predictor of fertility, says a researcher who has studied the best method of gauging the “window of fertility”.
That window is the six-day period during which conception can occur. It consists of the five days before ovulation and the day of ovulation itself.
But the greatest probability of conception results from intercourse one or two days before ovulation, not the day of ovulation as had been thought, says Dr Joseph B. Stanford, co-author of a review of fertility detection methods in the December issue of the journal Obstetrics and Gynecology and an associate professor in the department of family and preventive medicine at the University of Utah in Salt Lake City.
Calendar calculations and basal body temperature aren’t as useful as identifying the approximately five days leading up to ovulation. Urine tests for the surge of luteinising hormone that occurs a day or two before ovulation identify only a small part of the fertile window.
Methods that do reveal the complete window of fertility are those that evaluate changes in vaginal discharge or that assess oestrogen levels in urine or saliva.
The danger of acetaminophen
IT has long been known that too much acetaminophen can cause liver damage, but the alarming extent of the problem has just been documented. A new study has found that overdosing on acetaminophen, the most widely used non-prescription analgesic, was responsible for 39% of 308 cases of acute liver failure.
Most cases of liver toxicity from acetaminophen reported by the Acute Liver Failure Study Group, a consortium of 17 centres specialising in liver diseases in the United States, were accidental and not suicides. Seventy-nine percent of them were women.
“We don’t know if this is because women take more acetaminophen-containing drugs than men do, if women’s livers are more vulnerable, or if it’s because they are smaller,” says Dr William M. Lee, the principal investigator and professor of internal medicine at the University of Texas Southwestern Medical Centre in Dallas.
“We were surprised to find that the number of people with liver damage from acetaminophen was three times that of all other prescription drugs,” Lee says. He cautions people to be careful of how much they take and read the labels of all over-the-counter products taken together.
Mixing acetaminophen-containing medicines for cough, sleep and pain can add up to a dangerous dose. Most people in this study had taken more than 4,000mg of the drug. The study of cases over a 41-month period was reported in the Dec 17 Annals of Internal Medicine.
Earlier this year, a preliminary report of this study’s findings prompted a US Food and Drug Administration committee to advise that over-the-counter products containing acetaminophen – in pain relievers and cough-and-cold remedies – carry a stronger warning label than they currently do.
Mining the potential of selenium
WHETHER you get enough of the essential trace mineral selenium may depend, in part, on where you live. Research suggests that people who live in areas with low soil selenium levels (which affect the amount that gets into plants) have higher rates of some types of cancers.
Selenium contains antioxidants that could help protect the body from free-radical damage. It may also promote better functioning of the immune system and thyroid gland.
The recommended daily allowance for selenium is 55 micrograms, but some health experts think most people don’t get that much. Doses of 100 micrograms daily are recommended for disease prevention.
Doses higher than 400 micrograms per day should be avoided to prevent a toxicity condition called selenosis. Signs of selenosis include depression and nervousness.
Recently, scientists discovered a component of selenium that activates the tumour-suppressing gene, p53. This research might explain why adequate selenium levels might help prevent certain types of cancers. The US federal government is testing selenium for its potential to prevent prostate cancer. Ask your health-care provider for advice on selecting a brand. – LAT-WP