Computational and Mathematical Methods in Medicine
Volume 2012 (2012), Article ID 124861, 9 pages
http://dx.doi.org/10.1155/2012/124861
Research Article

The Relationship between Tuberculosis and Influenza Death during the Influenza (H1N1) Pandemic from 1918-19

Welling Oei1,2 and Hiroshi Nishiura2,3,4

1Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, 358GA Utrecht, The Netherlands
2Theoretical Epidemiology, Faculty of Veterinary Medicine, University of Utrecht, 3584CL Utrecht, The Netherlands
3School of Public Health, The University of Hong Kong, Level 6, Core F, Cyberport 3, Pokfulam, Hong Kong
4PRESTO, Japan Science and Technology Agency, Saitama 332-0012, Japan

Received 2 May 2012; Revised 28 May 2012; Accepted 4 June 2012

Academic Editor: Joe Wu

Copyright © 2012 Welling Oei and Hiroshi Nishiura. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The epidemiological mechanisms behind the W-shaped age-specific influenza mortality during the Spanish influenza (H1N1) pandemic 1918-19 have yet to be fully clarified. The present study aimed to develop a formal hypothesis: tuberculosis (TB) was associated with the W-shaped influenza mortality from 1918-19. Three pieces of epidemiological information were assessed: (i) the epidemic records containing the age-specific numbers of cases and deaths of influenza from 1918-19, (ii) an outbreak record of influenza in a Swiss TB sanatorium during the pandemic, and (iii) the age-dependent TB mortality over time in the early 20th century. Analyzing the data (i), we found that the W-shaped pattern was not only seen in mortality but also in the age-specific case fatality ratio, suggesting the presence of underlying age-specific risk factor(s) of influenza death among young adults. From the data (ii), TB was shown to be associated with influenza death (P=0.09), and there was no influenza death among non-TB controls. The data (iii) were analyzed by employing the age-period-cohort model, revealing harvesting effect in the period function of TB mortality shortly after the 1918-19 pandemic. These findings suggest that it is worthwhile to further explore the role of TB in characterizing the age-specific risk of influenza death.