209209 Associations between temperature, excessive heat events, and infectious gastroenteritis in US elderly

Tuesday, November 10, 2009: 1:10 PM

Kenneth K. H. Chui, PhD, MS/MPH , Department of Public Health and Community Medicine, Tufts University, Boston, MA
Elena Naumova, PhD , Department of Public Health and Community Medicine, Tufts School of Medicine, Boston, MA
Elderly are susceptible to the adverse health effects induced by excessive heat events (EHE), however, the association between EHE and gastroenteric illnesses is unclear. Hospitalization records in 1991–2004 involved gastrointestinal infections (GI: ICD 001–009 except Clostridium difficile) and symptoms (GS: ICD 558.9 and 787) in patients of age ≥65 were obtained from the Centers of Medicare and Medicaid Services and merged with daily maximal temperature from the National Climate Data Center in 16 metropolitan cities. Times to peak of the hospitalizations and temperature were determined using annual harmonic regression and contrasted. An EHE is defined as daily maximal temperature exceeding 90th–98th percentiles based on the 14-year long distribution. The resultant binary indicators were transformed into continuous exposure variables in order to carry over the “heat effects” across different incubation periods ranging from 1–40 days. In the 16 cities, annual rates of GI and GS were 11.9±1.31 and 140.4±8.9 cases per 10,000 elderly. They peaked around February and March, 15 days apart (GI: 45th±4 days; GS: 60th±4 days; r=0.66, p<0.01), while temperature peaked in August (205th±2 days). Despite such antiphase, on average, an EHE was significantly associated with an increase in GI-related hospitalizations by a factor of 1.24–5.95 in the following 11–38 days (p<0.05). For GS, all 16 cities demonstrated a positive association: hospitalizations increased by a factor of 1.10–1.42 over the 15–40 days after an EHE (p<0.01).

Learning Objectives:
1. Describe the seasonal patterns of gastrointestinal-symptoms-related hospitalizations among elderly and maximal temperature. 2. List two potential problems faced by health professionals in dealing with adverse effects caused by excessive heat events.

Keywords: Biostatistics, Infectious Diseases

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have an MPH degree in epidemiology and biostatistics. The abstract I am submitting is part of my current doctoral study.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.