Pneumonia ranks among the most common and deadliest hospital-acquired illnesses, killing 20%-30% of those it infects.

But a new study in the journal JAMA Internal Medicine suggests better oral hygiene could take a bite out of those numbers.

“There’s actually not that much in ICU medicine that we know is associated with decreased mortality in terms of prevention measures,” said co-author Dr. Michael Klompas of Harvard Medical School. “So to identify something that does appear to be associated with lower mortality — and that is simple, low-cost — is a very, very potent opportunity.”

Despite studies linking oral health to ailments ranging from cardiovascular disease to pregnancy complications, medicine largely treats the mouth and body separately.

The review of 15 studies and almost 2,800 patients found hospital-acquired pneumonia rates fell among patients randomly given daily toothbrushing, especially those on ventilators.

Those patients also got off respirators quicker, left ICUs faster and were less likely to die in intensive care.

Klompas said the policy implications are clear.

“We should be working hard to make routine oral care with toothbrushing part of the normative care for hospitalized patients,” he said.

More work remains to be done to determine whether the results apply outside the ICU.

“Almost all the evidence we have is in ICU patients on mechanical ventilation,” said Klompas. “And ironically, although ICU patients on mechanical ventilation are at higher risk of pneumonia, collectively across the hospital population, most pneumonias occur in non-ventilated patients because they are more of them.”