臺灣老年族群結核病危險因子分析

Abstract

背景 結核病是在全球導致生病及死亡的主要傳染病之一，雖然近年來結核病的發生率逐年下降，但仍需要更多努力來進一步控制疫情。在台灣，老年族群的結核病發生率至少是其他年齡層的三倍以上，為了進一步了解老年族群有高發生率的原因，我們進行了一個針對台灣老年族群的結核病危險因子分析，探討已知危險因子所造成的結核病風險以及尋找老年族群的新結核病危險因子，了解危險因子對於台灣老年族群結核病疫情造成的影響。 方法 研究族群是臺灣2001、2005及2009年國民健康訪問調查中大於65歲的參與者，使用結核病通報系統來定義新發生的結核病個案，納入的危險因子變項包括人口學、健康狀態、健康行為變項以及針對老年族群的特殊變項。我們計算暴露在不同危險因子時的發生率並使用Cox比例風險模式進行存活分析了解危險因子對於老年族群活動性結核發病所造成的風險。此外，我們還計算了危險因子的族群可歸因分率來觀察危險因子對於臺灣整體族群的實際影響。所有分析皆使用研究族群考慮抽樣方法的權重值，並使用SAS 9.4進行分析。 結果 經過了平均5.85年的追蹤，在4,657個參與者中有67個活動性結核病發病且有1,236個參與者在追蹤期間死亡。平均的結核病發生率為每十萬人年227 (95%CI: 179-288) 個病例。大於85歲、男性、BMI偏低以及有肺部疾病共病症的老人擁有較高的活動性結核病發病風險，肺部疾病共病症的族群可歸因分率為16.4%。但在研究結果中沒有發現新的老年族群結核病危險因子擁有統計上顯著結果。 結論 本研究結果顯示肺部疾病共病症與BMI偏低的老年人擁有顯著較高的結核病風險，雖然沒有辦法找到新的老年族群結核病危險因子，但老年族群在結核病疫情的重要性不可忽視且仍需要未來的研究進一步探討。

Introduction Tuberculosis (TB) is one of the leading infectious causes of mortality and morbidity in the world. Although the incidence rate has been decreasing slowly these years, there is still need efforts to prevent the disease. In Taiwan, the incidence of TB in the elderly is at least three times higher than in other age groups. To further understand the high incidence rate in the elderly, we conduct a risk factors analysis for the elderly population in Taiwan. We aim to indicate the real risk caused by well-known risk factors for TB among elders and identify novel elderly specific risk factors in Taiwan. Methods The study population was elderly participants from Taiwan’s 2001, 2005 and 2009 National Health Interview Survey (NHIS). Information for incident active TB cases was collected from the National TB registry dataset. Risk factors under consideration included demographic, health status, health behavior variables, and elderly specific variables. Incidence rates were calculated to show TB epidemic under exposure of different risk factors. Cox regression models were conducted to estimate hazard ratios for risk factors of TB and to find novel risk factors specific to the elderly. Population attributable fraction was calculated to show the impact of risk factors in Taiwan. All estimates accounted for study design were weighted. Results After average 5.85 years of follow-up, 67 TB cases occurred and 1,236 (26.5%) participants died among 4,657 participants. The incidence rate of TB during research period was 227 (95%CI: 179-288) per 100,000 person-year. Elderly with features of older age, male, low body mass index (BMI) or past history of lung disease had a significant association with active TB. If the distribution of lung disease was in a counterfactual situation, 16.4% of total cases could be prevented. Two novel risk factors show a positive result of increasing TB risk but without statistical significance. Conclusion Elderly population with past history of lung disease and low BMI status have significantly higher risk of active TB. Through findings in the study, the real effect of novel risk factors cannot be ascertained. The association between novel risk factors and active TB should be further explored through future research.