title: Age and Sex Differences in Rates of Influenza-Associated Hospitalizations in Hong Kong.
abstract: Few studies have explored age and sex differences in the disease burden of influenza, although men and women probably differ in their susceptibility to influenza infections. In this study, quasi-Poisson regression models were applied to weekly age- and sex-specific hospitalization numbers of pneumonia and influenza cases in the Hong Kong SAR, People's Republic of China, from 2004 to 2010. Age and sex differences were assessed by age- and sex-specific rates of excess hospitalization for influenza A subtypes A(H1N1), A(H3N2), and A(H1N1)pdm09 and influenza B, respectively. We found that, in children younger than 18 years, boys had a higher excess hospitalization rate than girls, with the male-to-female ratio of excess rate (MFR) ranging from 1.1 to 2.4. MFRs of hospitalization associated with different types/subtypes were less than 1.0 for adults younger than 40 years except for A(H3N2) (MFR = 1.6), while all the MFRs were equal to or higher than 1.0 in adults aged 40 years or more except for A(H1N1)pdm09 in elderly persons aged 65 years or more (MFR = 0.9). No MFR was found to be statistically significant (P < 0.05) for hospitalizations associated with influenza type/subtype. There is some limited evidence on age and sex differences in hospitalization associated with influenza in the subtropical city of Hong Kong.
authors.forename: Xi-Ling
authors.initials: XL
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.forename: Kwok-Hung
authors.initials: KH
authors.lastname: Chan
authors.forename: King-Pan
authors.initials: KP
authors.lastname: Chan
authors.forename: Pei-Hua
authors.initials: PH
authors.lastname: Cao
authors.forename: Eric Ho-Yin
authors.initials: EH
authors.lastname: Lau
authors.forename: J S Malik
authors.initials: JS
authors.lastname: Peiris
authors.forename: Chit-Ming
authors.initials: CM
authors.lastname: Wong
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification; D053122:Influenza A Virus, H3N2 Subtype / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D017678:Sex Distribution; D055815:Young Adult
keywords: age distribution; hospitalization; influenza; risk assessment; sex