2005-2019台灣A型肝炎流行病學及發生率趨勢分析

Epidemiology and incidence trend of hepatitis A in Taiwan, 2005-2019

葉維哲(Wei-Che Yeh)

指導教授 ： 方啟泰

國立臺灣大學/公共衛生學院/公共衛生碩士學位學程/碩士(2022年)

https://doi.org/10.6342/NTU202200139

摘要

背景
在台灣A型肝炎的發生率近年來，除了2015-2017年的群突發事件外，沒有明顯變動的趨勢。A型肝炎主要透過糞口途徑傳播，危險因子包含男男間性行為、食用受汙染的飲用水或食品、前往A型肝炎疫情高風險國家等。這些與行為及生活習慣相關的危險因子在年齡-年代-世代模型中大部分被歸類為世代效應。近年來，世界各國以全人口為基礎的研究顯示，在社經條件及生活環境較佳的已開發國家，A型肝炎的流行病學特性隨著公共衛生條件的改善而有所改變，高風險族群從早期的年幼族群(10歲以下)轉變成近年來以20-40歲族群為主，因此，疫情防治的相關政策及措施也應該隨之作相對應的調整。
材料與方法
利用台灣疾病管制署傳染病統計資料系統及傳染病年報，取得西元2005到2019 年間台灣A型肝炎通報個案的相關統計資料，計算不同性別的年齡標準化發生率。將這期間A型肝炎通報個案分為十四個年齡群 (0-4歲~65-69歲)、三個年代組 (2005-2009年、2010-2014年、2015-2019年)及與其相對應的十四個世代組 (1945出生世代~2015出生世代)。利用公平離差率年齡-年代-世代模型，分別得到年齡效應、年代效應以及世代效應，來進行分析。並且利用流行病學人、時、地三個要素與A型肝炎發生率之間的關係進行探討，找出台灣A型肝炎高風險族群。
結果
利用公平離差率年齡-年代-世代模型進行分析，台灣A型肝炎世代效應呈現先升後降的趨勢。從1980出生世代開始上升，到2000出生世代才開始逐漸下降一直到2015出生世代。台灣A型肝炎年代效應，於2015-2017經歷一個先升後降的A型肝炎群突發事件，除此之外，A型肝炎的年代效應在台灣並沒有明顯的趨勢。年齡效應則從年齡群15-19歲上升到25-29歲最高之後開始下降，一直到40歲以上年齡組降至年齡效應相對較低的水準。三者效應強弱依次為年齡效應，世代效應，最後才是年代效應。從流行病學人、時、地的角度分析，首先針對人的部分，本研究顯示台灣A型肝炎發生率男性較女性高，男性發生率約為女性的4.03倍。其次，針對地的部分，台灣A型肝炎發生率近十年以北部各縣市最高，外島各縣市最低，且不論是否為都會區，北部縣市發生率都較南部縣市高。最後，針對時的部分，台灣A型肝炎發生率與不同年代間並沒有產生互相影響的結果。
結論
本研究利用公平離差率年齡-年代-世代模型分析，結果顯示台灣A型肝炎發生率的年齡效應以及世代效應的趨勢相似，效應影響較高的族群主要集中在在1980-2000的出生世代 (年齡為20-40歲)，可發現台灣A型肝炎高風險族群從早年的10歲以下新生兒及幼童族群逐漸轉變為20-40歲青年族群。台灣A型肝炎防治相關政策也應該對於高風險族群的轉變作相對應的調整。

關鍵字

A型肝炎 ； 發生率 ； 年齡-年代-世代模型 ； 公平離差率 ； 年代效應 ； 世代效應 ； 年齡效應 ； A型肝炎疫苗

並列摘要

Background and Objectives
The incidence of hepatitis A in Taiwan has no evident trend for past 10 years, except for the outbreak from 2015-2017. The transmission of hepatitis A virus is primarily from person-to-person by the faecal-oral route. The main risk factors of Hepatitis A include man sex with man activity、intaking contaminated foods and water、traveling to high risk countries or regions etc. Such activities and lifestyle factors are regarded mostly as cohort effect in age-period-cohort model. In recent population-based study in developed countries shows that in high social-economic status and improved hygiene environment countries such as USA or Japan, the epidemiology features of Hepatitis A change over time. High risk groups of Hepatitis A in developed countries transformed from under 10 years old to 20-40 years old. Therefore , the policies of Hepatitis A prevention should be adjusted to reflect the transformative patterns of Hepatitis A epidemiology.
Materials and Methods
A population-based study was conducted using the database and infectious disease annual reports from Taiwan Control Disease Center between 2005 and 2019. Patients with Hepatitis A were identified and the incidence rates of Hepatitis A would be age-standardized with gender-specific measures. These cases were divided into 14 age groups (0-4~ 65-69), 3 time periods( 2005-2009、2010-2014、2015-2019), and 14 birth cohorts (1995~2005). Using constant-relative-variation age-period-cohort model to analyze the data for obtaining age effect， period effect， and cohort effect respectively. In addition, combining the relatives of three factors of epidemiology including person、 place and time with the incidences of Hepatitis A to find out the high-risk groups of Hepatitis A in Taiwan.
Results
The cohort effect of Hepatitis A in Taiwan shows the upper ward trend from the birth cohort of 1980 to 2000 and the downtrend from the birth cohort of 2000-2015. The period effect of Hepatitis A in Taiwan shows the First increased and then decreased trend from 2015-2017 because of experiencing the epidemic events of Hepatitis A. Additionally, the research indicates that the period effect of Hepatitis A has no clear trend in Taiwan. The age effect of Hepatitis A rises from the age group of 15-19 to 25-29. After passing 30 years old the trend of age effect declines until 40 years old which reaches the average level of the age effect in Taiwan. The age effect was the strongest, followed by the cohort effect and period effect. Analyzing from the perspective of three factors of epidemiology including person、place and time, the research shows that the incidence of Hepatitis A in males is 4.03 times higher than in females. Next, the incidence is highest in northern counties of Taiwan no matter it is a rural area or urban area. Lastly, the research shows that the incidence of Hepatitis A and different periods have no interaction and effect with each other.
Conclusions
The research utilizes the constant-relative-variation age-period-cohort model to process the analysis. The result of the research indicates that the incidence of Hepatitis A has familiar trends with age and the cohort effect. The age and the cohort effect are highly affecting on the birth cohort of 1980-2000(20-40 yrs old). With the interpretation of the result of this research, we can find that the high-risk group of Hepatitis A in Taiwan has transformed from infants and children who are under 10 years old to adults who are 20-40 years old. Above all, the government is mainly responsible for making disease prevention policies for Hepatitis A should adjust the direction to in line with the transformation of high-risk groups of Hepatitis A in Taiwan.

並列關鍵字

hepatitis A ； constant-relative-variation restriction ； incidence ； age-period-cohort model ； vaccine of hepatitis A ； age effect ； period effect ； cohort effect

參考文獻

1.Jacobsen KH. Globalization and the Changing Epidemiology of Hepatitis A Virus. Cold Spring Harb Perspect Med. 2018 Oct 1;8(10):a031716. doi: 10.1101/cshperspect.a031716. PMID: 29500305; PMCID: PMC6169986.

2.Melnick JL. Properties and classification of hepatitis A virus. Vaccine 1992;10.

3.Melnick JL. History and epidemiology of hepatitis A virus. J Infect Dis 1995;171 Suppl:S2–8.

4.Jacobsen KH， Wiersma ST. Hepatitis A virus seroprevalence by age and world region， 1990 and 2005. Vaccine 2010;28(41):6653–7.

5.Martin A， Lemon SM. Hepatitis A virus: from discovery to vaccines. Hepatology 2006;43.