Section for Microbiology and Immunology, The Gade Institute, University of Bergen, Bergen, Norway.
BMC Infect Dis. 2010 Feb 23;10:37. doi: 10.1186/1471-2334-10-37.
To investigate how the risk of active tuberculosis disease is influenced by time since original infection and to determine whether the risk of reactivation of tuberculosis increases or decreases with age.
Cohort analysis of data for the separate ten year birth cohorts of 1876-1885 to 1959-1968 obtained from Statistics Norway and the National Tuberculosis Registry. These data were used to calculate the rates and the changes in the rates of bacillary (or active) tuberculosis. Data on bacillary tuberculosis for adult (20+) age groups were obtained from the National Tuberculosis Registry and Statistics Norway from 1946 to 1974. Most cases during this period arose due to reactivation of remote infection. Participants in this part of the analysis were all reported active tuberculosis cases in Norway from 1946 to 1974 as recorded in the National Tuberculosis Registry.
Tuberculosis decreased at a relatively steady rate when following individual birth cohorts, but with a tendency of slower decline as time passed since infection. A mean estimate of this rate of decline was 57% in a 10 year period.
The risk of reactivation of latent tuberculosis decreases with age. This decline may reflect the rate at which latent tuberculosis is eliminated from a population with minimal transmission of tubercle bacilli. A model for risk of developing active tuberculosis as a function of time since infection shows that the rate at which tuberculosis can be eliminated from a society can be quite substantial if new infections are effectively prevented. The findings clearly indicate that preventative measures against transmission of tuberculosis will be the most effective. These results also suggest that the total population harbouring live tubercle bacilli and consequently the future projection for increased incidence of tuberculosis in the world is probably overestimated.
本研究旨在探讨初次感染后时间对活动性结核病发病风险的影响，并确定结核病复发风险是否随年龄增长而增加或降低。
对挪威统计局和国家结核病登记处分别收集的 1876-1885 年至 1959-1968 年的十个十年出生队列的队列数据进行分析。这些数据用于计算菌（或活动性）结核的发病率和发病率变化。成人（20 岁以上）年龄组的菌型结核数据来源于国家结核病登记处和挪威统计局 1946 年至 1974 年的数据。在此期间，大多数病例均由潜伏感染复发引起。本分析部分的参与者均为挪威国家结核病登记处报告的 1946 年至 1974 年的活动性结核病例。
当追踪各个人群的出生队列时，结核病的发病率呈相对稳定的下降趋势，但随着感染后时间的推移，下降趋势逐渐变缓。平均估计该下降速度为每 10 年 57%。
潜伏性结核复发的风险随年龄增长而降低。这种下降可能反映了在结核分枝杆菌传播最小的人群中，潜伏性结核被消除的速度。以感染后时间为函数的活动性结核病发病风险模型表明，如果能有效预防新的感染，结核分枝杆菌从一个社会中被消除的速度可能相当可观。这些发现清楚地表明，预防结核病传播的措施将是最有效的。这些结果还表明，全球携带活结核分枝杆菌的总人口以及由此产生的未来结核病发病率增加的预测可能被高估了。
