Epidemiology and Infection



Influenza and pneumonia hospitalizations in Ontario: a time-series analysis


ERIC J. CRIGHTON a1c1, RAHIM MOINEDDIN a2a3, MUHAMMAD MAMDANI a4a5a6 and ROSS E. G. UPSHUR a1a2a3
a1 Primary Care Research Unit, Sunnybrook and Women's College Health Sciences Centre, Toronto, ON, Canada
a2 Department of Family and Community Medicine, University of Toronto, Toronto, ON, Canada
a3 Department of Public Health Sciences, University of Toronto, Toronto, ON, Canada
a4 Institute for Clinical Evaluative Sciences, Toronto, ON, Canada
a5 Health Policy Management and Evaluation, University of Toronto, Toronto, ON, Canada
a6 Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada

Article author query
crighton ej   [PubMed][Google Scholar] 
moineddin r   [PubMed][Google Scholar] 
mamdani m   [PubMed][Google Scholar] 
upshur re   [PubMed][Google Scholar] 

Abstract

A comprehensive examination of gender and age-specific influenza and pneumonia hospitalization seasonality is currently lacking. Using population-based data for Ontario, Canada between April 1988 and March 2002 (n=339803 hospitalizations), findings from this study revealed clear seasonality [Fisher's Kappa (FK) test=68·64, P<0·001; Bartlett's Kolmogorov–Smirnov (BKS) test=0·68, P<0·001] with consistent summer troughs and winter peaks for both sexes and all ages combined. The very young (both sexes 0–4 years) demonstrated the strongest seasonality (Rautoreg2=0·97) and females aged 10–19 years, the weakest (Rautoreg2=0·59). Gender differences were most pronounced in the oldest age groups (80+ years) where females had an average annualized peak rate of 250/100000 compared to 400/100000 for males. These findings can contribute to more population-specific prevention strategies and effective resource and service allocation based on seasonal and specific population demands.

(Accepted June 30 2004)


Correspondence:
c1 E. Crighton, Primary Care Research Unit, Sunnybrook and Women's College Health Sciences Centre, 2075 Bayview Ave, no. E-349, Toronto, ON, Canada M4N 3M5. (Email: eric.crighton@sw.ca)


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