Dental plaque risk and cancer
If you have persistent dental plaque, it may be associated with an increased risk of dying early from cancer.
That’s according to an observational study published June 11 in the online journal, BMJ Open. It doesn’t necessarily mean that dental plaque causes cancer, say the authors, but controlling bacteria in the oral cavity may boost one’s health by reducing a source of inflammation.
Dental plaque is made up of a film of bacteria that covers the surfaces of the teeth, including the gaps between the teeth and gums. It leads to tooth decay and gum inflammation, with the potential for tooth loss, and has been implicated in systemic health problems.
For the study, researchers wanted to find out if plaque might be a risk factor for early death from cancer due to infection and inflammation, both of which are thought to have a role in up to one in five cancers. To accomplish this, they tracked the health of almost 1,400 randomly selected Swedish adults from Stockholm for 24 years (1985-2009). Participants were in their 30s and 40s at the start of the monitoring period, and were all quizzed about factors likely to increase their cancer risk, such as smoking and levels of affluence.
Participants’ mouth hygiene was also assessed to investigate their levels of dental plaque, tartar, gum disease and tooth loss. While they had no overt gum disease, participants did have substantial levels of plaque on the tooth surface.
By 2009, 58 people had died of cancer—around a third of whom were women (35.6 percent). The average age of death was 61 for the women and 60 for the men. The women would have been expected to live around 13 years longer, and the men an additional 8.5 years, so their deaths could be considered premature, say the authors of the study, “The Association of Dental Plaque With Cancer Mortality in Sweden: A Longitudinal Study.”
Deaths among the women were predominantly caused by breast cancer while those among the men were attributed to a range of different cancers. The dental plaque index in those who died was higher than those who had survived, with values of 0.84 to 0.91—indicating that the gum area of the teeth had been covered with plaque. The values among the survivors were consistently lower (0.66 to 0.67)—indicating that the gum area was only partially covered with plaque.
When all the risk factors were considered, age almost doubled the risk of a cancer death. Male gender increased the odds by 90 percent.
After the other potential risk factors known to be associated with premature death—such as lower educational attainment, smoking, frequency of dental visits, and lower income—were accounted for, the associations observed between age, male gender, amount of dental plaque and premature death remained strong.
Dental plaque was associated with a significantly (79 percent) increased risk of premature death, although the absolute risk of premature death was low, with only 58 out of 1,390 participants dying after 24 years.
However, the authors caution that their findings do not prove that dental plaque causes or definitely contributes to cancer.
“Our study hypothesis was confirmed by the finding that poor [mouth] hygiene, as reflected in the amount of dental plaque, was associated with increased cancer mortality,” they write in BMJ Open. “Further studies are required to determine whether there is any causal element in the observed association.”
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