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Conference Paper: Obesity and influenza associated mortality risks in an elderly cohort

TitleObesity and influenza associated mortality risks in an elderly cohort
Authors
Issue Date2012
PublisherISIRV.
Citation
ISIRV International Conference on Seasonal and Pandemic Influenza, Munich, Germany, 5-8 September 2012. In Incidence, Severity, and Impact 2012: poster presentations, 2012, p. 10-11, abstract S1-P008 How to Cite?
AbstractBACKGROUND: Obesity has never been identified as a risk factor for severe outcomes of influenza until the 2009 H1N1 pandemic. Few studies have explored the effect of obesity on influenza-associated mortality. OBJECTIVES: This study assessed the modifying effects of obesity on influenza-associated mortality risks using the data collected from a cohort of elderly patients. METHODS: A total of 66,820 elderly Chinese patients in Hong Kong, with a follow-up period of 1998-2009, were divided into 4 groups following the Asian adult criteria, according to their body mass indexes (BMI) at the baseline. These groups were underweight (BMI, <18.5), normal weight (BMI, 18.5-22.9), overweight (BMI, 23.0-24.9), obesity I (BMI, 25.0-29.9), and obesity II (BMI, ≥30). We adopted the Cox proportional model with time dependent covariates to estimate the excess risks of mortality associated with 10% increase of influenza activity (measured by weekly proportions of specimens positive for influenza). Modifying effects of obesity were assessed by interaction terms defined by products of influenza activity and obesity dummy variables, while other lifestyle factors and seasonal confounders were simultaneously adjusted for in the model. RESULTS: The interaction of obesity and influenza activity was found statistically significant in all-cause mortality (P < .05), but not in respiratory diseases, pneumonia, and influenza. Compared to the elderly patients with normal weight, underweight and obese elderly patients had higher mortality risks for these 3 disease categories, whereas overweight elderly patients had lower risks. Stratified analysis found that the hazard ratio of all-cause mortality associated with every 10% increase in influenza virus activity was 1.081 (95% CI, 1.013-1.154), 1.047 (95% CI, 1.012-1.084), 0.981 (95% CI, 0.936-1.028), 1.018 (95% CI, 0.980-1.058), and 1.062 (95% CI, 0.972-1.162) in the underweight, normal, overweight, obesity I, and obesity II groups, respectively. CONCLUSIONS: Both being underweight and obesity were associated with increased mortality risks attributable to influenza in Chinese elderly patients in Hong Kong
DescriptionPoster Presentations: S1-P008
Persistent Identifierhttp://hdl.handle.net/10722/181843

 

DC FieldValueLanguage
dc.contributor.authorYang, Len_US
dc.contributor.authorChan, KPen_US
dc.contributor.authorLee, RSYen_US
dc.contributor.authorChan, WMen_US
dc.contributor.authorLai, HKen_US
dc.contributor.authorThach, TQen_US
dc.contributor.authorLam, THen_US
dc.contributor.authorPeiris, JSMen_US
dc.contributor.authorWong, CMen_US
dc.date.accessioned2013-03-19T04:02:34Z-
dc.date.available2013-03-19T04:02:34Z-
dc.date.issued2012en_US
dc.identifier.citationISIRV International Conference on Seasonal and Pandemic Influenza, Munich, Germany, 5-8 September 2012. In Incidence, Severity, and Impact 2012: poster presentations, 2012, p. 10-11, abstract S1-P008en_US
dc.identifier.urihttp://hdl.handle.net/10722/181843-
dc.descriptionPoster Presentations: S1-P008-
dc.description.abstractBACKGROUND: Obesity has never been identified as a risk factor for severe outcomes of influenza until the 2009 H1N1 pandemic. Few studies have explored the effect of obesity on influenza-associated mortality. OBJECTIVES: This study assessed the modifying effects of obesity on influenza-associated mortality risks using the data collected from a cohort of elderly patients. METHODS: A total of 66,820 elderly Chinese patients in Hong Kong, with a follow-up period of 1998-2009, were divided into 4 groups following the Asian adult criteria, according to their body mass indexes (BMI) at the baseline. These groups were underweight (BMI, <18.5), normal weight (BMI, 18.5-22.9), overweight (BMI, 23.0-24.9), obesity I (BMI, 25.0-29.9), and obesity II (BMI, ≥30). We adopted the Cox proportional model with time dependent covariates to estimate the excess risks of mortality associated with 10% increase of influenza activity (measured by weekly proportions of specimens positive for influenza). Modifying effects of obesity were assessed by interaction terms defined by products of influenza activity and obesity dummy variables, while other lifestyle factors and seasonal confounders were simultaneously adjusted for in the model. RESULTS: The interaction of obesity and influenza activity was found statistically significant in all-cause mortality (P < .05), but not in respiratory diseases, pneumonia, and influenza. Compared to the elderly patients with normal weight, underweight and obese elderly patients had higher mortality risks for these 3 disease categories, whereas overweight elderly patients had lower risks. Stratified analysis found that the hazard ratio of all-cause mortality associated with every 10% increase in influenza virus activity was 1.081 (95% CI, 1.013-1.154), 1.047 (95% CI, 1.012-1.084), 0.981 (95% CI, 0.936-1.028), 1.018 (95% CI, 0.980-1.058), and 1.062 (95% CI, 0.972-1.162) in the underweight, normal, overweight, obesity I, and obesity II groups, respectively. CONCLUSIONS: Both being underweight and obesity were associated with increased mortality risks attributable to influenza in Chinese elderly patients in Hong Kong-
dc.languageengen_US
dc.publisherISIRV.en_US
dc.relation.ispartofIncidence, Severity, and Impact 2012: poster presentationsen_US
dc.titleObesity and influenza associated mortality risks in an elderly cohorten_US
dc.typeConference_Paperen_US
dc.identifier.emailYang, L: linyang@hku.hken_US
dc.identifier.emailChan, KP: kpchanaa@hku.hken_US
dc.identifier.emailLai, HK: laihk@hku.hken_US
dc.identifier.emailThach, TQ: thach@hku.hken_US
dc.identifier.emailLam, TH: hrmrlth@hkucc.hku.hken_US
dc.identifier.emailPeiris, JSM: malik@hkucc.hku.hken_US
dc.identifier.emailWong, CM: hrmrwcm@hku.hken_US
dc.identifier.authorityLai, HK=rp01527en_US
dc.identifier.authorityThach, TQ=rp00450en_US
dc.identifier.authorityLam, TH=rp00326en_US
dc.identifier.authorityPeiris, JSM=rp00410en_US
dc.identifier.authorityWong, CM=rp00338en_US
dc.description.naturelink_to_OA_fulltext-
dc.identifier.hkuros213696en_US
dc.identifier.spage10en_US
dc.identifier.epage11en_US
dc.publisher.placeGermany-

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