Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, 358GA Utrecht, The Netherlands.
Comput Math Methods Med. 2012;2012:124861. doi: 10.1155/2012/124861. Epub 2012 Jul 17.
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.
1918-19 年西班牙流感（H1N1）大流行期间，流感特异性年龄相关死亡率呈 W 型的背后的流行病学机制尚未完全阐明。本研究旨在提出一个正式假设：结核病（TB）与 1918-19 年的流感 W 型死亡率有关。评估了三条流行病学信息：（i）包含 1918-19 年流感的年龄特异性病例和死亡人数的流行记录，（ii）大流行期间瑞士结核病疗养院的流感爆发记录，以及（iii）20 世纪初随时间推移的年龄依赖性结核病死亡率。分析数据（i），我们发现 W 型模式不仅见于死亡率，也见于年龄特异性病死率，表明年轻成年人中存在流感死亡的潜在年龄特异性危险因素。从数据（ii）来看，TB 与流感死亡相关（P=0.09），而非 TB 对照组中没有流感死亡。通过使用年龄-时期-队列模型分析数据（iii），揭示了 1918-19 大流行后不久，TB 死亡率的时期函数中存在收割效应。这些发现表明，进一步探讨 TB 在描述流感死亡的年龄特异性风险方面的作用是值得的。
