Health Day

There may be another good reason to floss each day: A new study finds that gum disease could raise the risk for cancer.

“Men with history of periodontal disease had a 14 percent higher risk of cancer than those who did not have periodontal disease, and the increase persisted among never smokers,” said lead researcher Dominique Michaud, a cancer epidemiologist at Imperial College London, in the U.K.

People with gum infections do have an increased amount of inflammatory markers circulating in their blood, and inflammation has been linked to cancer, experts say. But the exact link, if any, between gum disease and cancer remains unclear.

This new finding needs to be examined in other populations and among women, but it at least suggests that oral health may have some impact on cancer risk, Michaud said.

“If other data can support this association, then it will have implications for prevention and may provide some new clues on the role of the immune function in cancer development,” Michaud said.

The report is published in the June edition of the journal The Lancet Oncology.

In the study, Michaud’s team collected data on more than 48,000 American men who participated in the Health Professionals Follow-Up study, which included health professionals aged 40 to 75.

During an average of 17.7 years of follow-up, 5,720 cancer cases were reported. These cases excluded non-melanoma skin cancer and non-aggressive prostate cancer. The most common cancers reported were colorectal, melanoma, lung and bladder and advanced prostate cancer, Michaud’s group found.

After taking into account other risk factors, such as smoking and diet, the researchers found that men with a history of gum disease had a 14 percent higher risk of developing cancer compared with men did not have a history of the condition.

While the overall risk was 14 percent, the risk for specific cancers was typically higher. Compared to men with healthy gums, men with a history of gum disease had a 36 percent increased risk of lung cancer, a 49 percent hike in risk of kidney cancer, a 54 percent higher risk of pancreatic cancer, and a 30 percent increased risk of white blood cell cancers.

In addition, men who had fewer teeth at the beginning of the study had a 70 percent increased risk of developing lung cancer, compared with men who had 25 to 32 teeth, Michaud’s team found.

However, the association between gum disease and lung cancer disappeared among men with gum disease who had never smoked, the team noted. Men with gum disease who did not smoke still had a 35 percent increased risk for blood cancers, however, and a 21 percent overall increased risk for cancer.

One expert believes that the increased risk found in the study is too small to conclude that gum disease is a major risk factor for cancer.

“I am not very impressed with the finding,” said Dr. Eva S. Schernhammer, an assistant professor, medicine and public health at Harvard Medical School and School of Public Health. “It’s a really modest increased risk. I am not sure I would make too much out of it,” she said.

“If this is a true association, it could be a marker of socioeconomic status, or a marker for some inflammatory process that leads to cancer,” Schernhammer reasoned. “Given the small increase in risk, I’m not sure it would lead to major, dramatic changes in anything” in terms of public health policy, she said.

A stomach bacterium called Helicobacter pylori may reduce a child’s risk of developing asthma by as much as 50 percent, a new study suggests.

H. pylori has been present in the human stomach probably since humans were humans. However, the germ began disappearing over the course of the 20th century with the introduction of antibiotics and cleaner water and homes, perhaps making children more susceptible to asthma, the study authors suggested.

“In our study we asked the question, is there any relationship between having H. pylori in the stomach and having asthma and other allergic disorders,” said lead researcher Dr. Martin J. Blaser, the Frederick H. King Professor of Internal Medicine and chairman of the department of medicine at the New York University Langone Medical Center in New York City.

“We found a strong inverse association between H. pylori and childhood asthma, childhood hay fever and childhood allergies,” added Blaser, who’s also a professor of microbiology and has studied H. pylori for more than two decades.

Blaser thinks that H. pylori may protect the body against asthma. “When children have H. pylori in their stomach, their immune system is different than if they don’t have H. pylori,” he said.

H. pylori has been disappearing especially since World War II, which is when the incidence of asthma began increasing, Blaser said.

For the study, Blaser and his colleague Yu Chen, an assistant professor of epidemiology, collected data on 7,412 children who participated in the 1999 to 2000 National Health and Nutrition Examination Survey IV, conducted by the National Center for Health Statistics.

Among children in the survey, just 5.4 percent born in the 1990s tested positive for H. pylori. In addition, 11.3 percent of the children under 10 had taken antibiotics in the month before the survey.

Blaser and Chen found that among children 3 to 13 years of age, those who carried the stomach bug were 59 percent less likely to develop asthma than children without H. pylori. These children were also 40 percent less likely to suffer from hay fever and other allergies, such as eczema or rash.

Among children aged 3 to 19, the researchers found that those who harbored H. pylori reduced their risk of asthma by 25 percent.

“This is a new way of saying who’s at risk for asthma and who’s not,” Blaser said. “You can’t mess with Mother Nature. This bacterium that has been present forever in the human stomach has been disappearing, and that has consequences.”

Some of the consequences are good, however, Blaser noted. These include the decline of ulcers and decreases in stomach cancer among adults, he said. “But these are diseases of old age,” he said. “It is possible that H. pylori may be protective of children, but bad for old people.”

The study findings were published online July 15 in The Journal of Infectious Diseases.

Dr. Clifford Bassett, medical director of Allergy and Asthma Care of New York in New York City, thinks the findings open a new window on doctors’ understanding of asthma and allergies.

“It appears this will add to our knowledge and research looking at incidence and prevalence of asthma and allergic diseases in children and adults in an increasingly sanitized world,” he said. “The relevance of H. pylori as a potential risk in asthma is quite thought-provoking by any means.”

There’s some truth to the old wives’ tale that “for every child, the mother loses a tooth,” according to a New York University professor who found that women with more children are more likely to have missing teeth.

Dr. Stefanie Russell, an assistant professor of epidemiology and health promotion, examined data on 2,635 women, ages 18 to 64, who reported at least one pregnancy in the Third National Health and Nutrition Examination Survey.

The findings were published online in the American Journal of Public Health.

“This is the first time we’ve seen a connection between pregnancy and tooth loss affecting women at all socioeconomic levels in a large, heterogeneous sample of the U.S. population,” Russell said in a prepared statement.

Certain biological and behavioral changes related to pregnancy and childbirth may be the cause of this tooth loss, Russell said:

• Pregnancy can make women more prone to gingivitis (gum inflammation), and repeated pregnancies can result in more frequent outbreaks of gingivitis that may cause tooth loss in women with periodontitis.
• Women may delay dental treatment due to financial concerns related to having children.
• Caring for children may lead a mother to reduce the time she spends on her own oral health.

“Although further research is needed on the specific reasons for the link between pregnancy and tooth loss, it is clear that women with multiple children need to be especially vigilant about their oral health,” Russell said.

“We, as a society, need to be more aware of the challenges that women with children may face in getting access to dental care. That means offering these women the resources and support they need, which can be as simple as making sure a working mother gets time off from work to see the dentist.”