https://www.smh.com.au-By Lizzie Roberts
Poor oral hygiene and gum disease could promote the formation of bacteria known to cause gastric cancer.Credit:iStock
Brushing your teeth regularly could help ward off cancer, a Harvard University study suggests, after it found gum disease increases the risk of throat and stomach cancer by 50 per cent.
The risk was even higher among those who had previously lost teeth, the research found. Gum disease has previously been found to lead to heart problems as bacteria spread through the blood.
But the new research, by scientists from Harvard T.H. Chan School of Public Health in Boston, looked at oesophageal (throat) and gastric (stomach) cancer rates in 98,459 women and 49,685 men over a period of more than 20 years.
Dental measures, demographics, lifestyle, and diet were assessed using follow-up questionnaires and self-reported cancer diagnosis was confirmed after reviewing medical records.
The results showed that during 22 to 28 years of follow-up, there were 199 cases of oesophageal cancer and 238 cases of gastric cancer. A history of gum disease was associated with a 43 per cent and 52 per cent increased risk of oesophageal cancer and gastric cancer respectively, the study found.
Compared to people with no tooth loss, the risks of oesophageal and gastric cancer for those who lost two or more teeth were also modestly higher – 42 per cent and 33 per cent respectively.
Those with a history of gum disease, and who may or may not have had tooth loss, were equally linked with a 59 per cent increased risk of oesophageal cancer compared to those with no history of periodontal disease and no tooth-loss.
Those with a history of gum disease and no tooth-loss had a 50 per cent increased risk of gastric cancer, which rose to 68 per cent for those with a history of gum disease and tooth-loss, compared to those with no history and no loss.
A link between bacteria commonly found in the mouth and oesophageal cancer has been made by other scientists in previous studies.
Another possible reason is that poor oral hygiene and gum disease could promote the formation of bacteria known to cause gastric cancer, scientists said.
But mild cases of gum disease can commonly be treated with good oral hygiene, including brushing your teeth twice a day and flossing. Previous findings on the relationship of gum disease and tooth loss with oesophageal and gastric cancer have been inconsistent, the authors said.
One observational study published in the BMJ Open in 2012 examined the link between dental plaque and premature cancer death.
After 24 years, 58 of the 1,390 participants had died, 35 as a result of cancer, and those who died had a significantly higher quantity of dental plaque than the survivors.
But the authors warned their findings did not prove that plaque definitively causes cancer.
In this study, published in the journal Gut, the large sample size, long-term follow-up of the patients, and “rigorous control” for lifestyle impacts, adds strength to the findings, Dr Mingyang Song, one of the authors, told The Telegraph, London.
They concluded: “Together, these data support the importance of oral microbiome in oesophageal and gastric cancer.
“Further prospective studies that directly assess oral microbiome are warranted to identify specific oral bacteria responsible for this relationship.”
Dr Song said: “This research will ultimately lead to new microbiome-based prevention strategies for these cancers.”
The Telegraph, London