Infectious Diseases

BOSTON – Community-dwelling seniors who brush their teeth, keep as active as their infirmities permit, and shun cigarettes may be able to significantly lower their risk for serious pneumonia, investigators reported at the annual meeting of the Infectious Diseases Society of America.

Among 1,575 adults aged 70 years and older who were followed in an ongoing prospective study, a higher oral plaque burden was associated with a 1.43-fold greater risk for pneumonia that required hospitalization; the development of a mobility limitation was linked to 1.84-fold increased risk, and an active smoking status effectively doubled the risk (1.95-fold), reported Dr. Manisha Juthani-Mehta of Yale University in New Haven, Conn.

"The novel and interesting thing from this study is that these findings are consistent with the emerging theme linking oral bacteria (and therefore, potentially, the oral microbiome) to pneumonia risk in many different clinical settings – not only hospital-acquired pneumonia and ventilator-associated pneumonia, but now potentially ... community-acquired pneumonia, where aspiration may be a predominant mechanism for risk pneumonia in community-dwelling older adults as well," she said.

Dental plaque has been identified as a reservoir for respiratory pathogens implicated in hospital-acquired and ventilator-associated pneumonia, and her group has identified inadequate oral care as a risk factor for nursing home–acquired pneumonia, Dr. Juthani-Mehta said.

Whether dental plaque or poor oral hygiene also puts presumably healthy, community-dwelling older adults at greater risk for developing serious pneumonia was unclear, however.

The investigators hypothesized that in addition to inadequate dental care, modifiable risk factors for pneumonia would include lack of influenza and Pneumovax vaccinations, poor nutrition (body mass index loss), and cigarette smoking.

The overall Health ABC study cohort included 3,075 community-dwelling adults in Pittsburgh and Memphis who were aged 70-79 years at baseline. Of that group, 1,575 had a study interview within 6 months of a dental exam and had an available plaque score.

The authors defined poor oral hygiene as a mean oral plaque score of 1 or greater on a scale of 0-3 (0 = no plaque; 1 = plaque identified by a probe; 2 = visible plaque; 3 = abundant plaque).

The rate of pneumonia cases requiring hospitalization (the primary outcome) was 169.8 per 10,000 person-years, which was similar to that of the overall population rate for people aged 65 years and older (161.0 per 10,000 person-years in 2007, according to a 2010 National Health Statistics Report).

In a multivariate analysis, modifiable risk factors were mean oral plaque score (hazard ratio, 1.43), incident mobility limitation (HR, 1.84), and active smoking (HR, 1.95).

Nonmodifiable risk factors included male sex (HR, 2.08), white race (HR, 1.67), and age older than 75 years (HR, 1.32).

Looking at the average attributable fraction for each of the risk factors, the investigators found that the plaque score accounted for 13.1% of pneumonias, mobility limitation accounted for 12.2%, and smoking for 1.1%.

The study was supported by grants from the National Institutes for Health. Dr. Juthani-Mehta reported that she had no relevant financial disclosures.

10/24/11  

---

FROM THE ANNUAL MEETING OF THE INFECTIOUS DISEASES SOCIETY OF AMERICA

---

Vitals

Major Finding: Community-dwelling older adults with a mean oral plaque score equal to or greater than 1 were 43% more likely to develop pneumonia that required hospitalization.

Data Source: A prospective cohort study.

Disclosures: The study was supported by grants from the National Institutes for Health. Dr. Juthani-Mehta reported that she had no relevant financial disclosures.