An observational study featured in the online journal BMJ Open reveals that persistent dental plaque can potentially raise the risk of dying early from cancer.

Dental plaque is formed by colonizing bacteria that attach to the surface of teeth and gums, leading to tooth decay and inflammation of the gum, which can result in loss of teeth in some cases, as well as lead to other systemic health problems.

Researchers decided to establish whether dental plaque may influence the risk of early death from cancer due to infection and inflammation, as both factors are believed to play a role in up to one in five different types of cancer.

They monitored nearly 1,400 randomly selected adults from Stockholm aged between 30 and 40 years at the start of the study from 1985 to 2009. At the start of the study, all participants were questioned about factors that could increase their risk of cancer, such as levels of affluence and their smoking habits. The team also examined each participant’s mouth hygiene, with regard to the levels of dental plaque, tartar, gum disease, and tooth loss, and discovered that although none of the participants suffered from overt gum disease, they did have substantial levels of plaque on their teeth.

At the end of the study in 2009, the team registered 58 deaths of which about a third (35.6%) were women and 35 of these deaths were due to cancer. The average age of the deceased was 61 year for women and 60 years for the men. The women’s life expectancy would have been about 13 years longer, whilst that of the men would have been 8.5 years longer, which places them into the ‘premature deaths’ category. Whilst the women predominantly died from breast cancer, the men’s deaths were caused by a various different cancers.

The researchers observed that the deceased had a higher dental plaque index, compared with the survivors. Their values ranged from 0.84 to 0.91, which suggests the gums of their teeth were covered with plaque, whilst that of the survivors was consistently lower, i.e. 0.66 to 0.67, suggesting a partial cover with dental plaque. After accounting for all risk factors the team discovered that the risk of dying from cancer was almost two-fold with age, and that male gender had a 90% increased risk.

The results remained strong, even a fter accounting for other potential risk factors that are linked to premature death, as for instance smoking, lower educational attainment, frequency of dental visits, and lower income, the link between age, male gender as well as the amount of dental plaque.

The findings revealed that dental plaque was linked to a substantially higher risk (79%) of premature death. However, the overall risk of premature death remained low, with a death rate of only 58 participants from a total of 1,390 participants after 24 years. The team highlights that their findings provide no evidence that dental plaque in fact causes or definitely contributes to cancer.

They conclude:

“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. Further studies are required to determine whether there is any causal element in the observed association.”

Written By Petra Rattue