title: Body mass index and the risk of infections in institutionalised geriatric patients.
abstract: The objective was to examine the effect of BMI on the incidence of various infectious diseases in institutionalised, geriatric subjects. In a retrospective cohort study we analysed medical records of 619 patients aged 75 years and older (mean age 87.6 (sd 6.4) years) who were treated in a geriatric hospital in Vienna, Austria. The total incidence rate of infection in this population was 0.80 per person-year. The most frequent infections were urinary tract infections (0.30 per person-year), followed by infections of the lower respiratory tract (0.19 per person-year), diarrhoea (0.12 per person-year) and other infections (0.20 per person-year). Incidence risk ratios were obtained by a multiplicative Poisson regression model. There was a J-shaped curve in the incidence of infections recorded by BMI with a nadir at 27-28 kg/m2. Compared with the reference group with a BMI of 24-27.9 kg/m2, subjects with a lower BMI had a higher incidence rate of infections. The incidence risk ratios, adjusted for sex, age and chronic diseases, were 1.62 (95 % CI 1.21, 2.17) for those with a BMI of < 20 kg/m2 and 1.84 (95 % CI 1.40, 2.42) for those with a BMI of 20-23.9 kg/m2. However, also patients with a BMI of 28 kg/m2 and above had a higher incidence rate of infections, with an incidence risk ratio of 1.54 (95 % CI 1.07, 2.22). These results show that both underweight and obesity are associated with a higher risk of infections in institutionalised geriatric patients.
authors.affiliation: Institute of Social Medicine and Epidemiology, Medical University Graz, Graz, Austria. thomas.dorner@medunigraz.at
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Dorner
authors.forename: Franz
authors.initials: F
authors.lastname: Schwarz
authors.forename: Alexander
authors.initials: A
authors.lastname: Kranz
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Freidl
authors.forename: Anita
authors.initials: A
authors.lastname: Rieder
authors.forename: Christoph
authors.initials: C
authors.lastname: Gisinger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001317:Austria / Q000453:epidemiology; D015992:Body Mass Index; D003141:Communicable Diseases / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D008297:Male; D009765:Obesity / Q000150:complications*; D016012:Poisson Distribution; D012016:Reference Values; D012141:Respiratory Tract Infections / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D013851:Thinness / Q000150:complications*; D014552:Urinary Tract Infections / Q000453:epidemiology