幽門螺旋桿菌指標個案篩檢法：烏來區之初探性研究

Abstract

背景：胃幽門螺旋桿菌感染在台灣是個相當普遍的感染，盛行率約為四成。胃幽門螺旋桿菌也被認為和胃癌有關，約有九成以上非賁門胃癌患者有胃幽門螺旋桿菌感染。雖然胃幽門桿菌引起的慢性發炎可能造成的後果很嚴重，但是胃幽門桿菌的感染可能是無症狀感染或非特異性的症狀。胃幽門桿菌感染的危險因子包括：社會經濟地位、生活水準(家戶成員多寡、個人衛生習慣)和是否有自來水…等。在台灣東部以社區為單位的篩檢發現胃幽門螺旋桿菌在原住民族群的盛行率為六成，相對於非原住民族群高出很多。根據衛生福利部的統計資料顯示，原住民族群的胃癌發生率和致死率分別是非原住民族的2.19倍和2.47倍。 目的：本次研究的目的首先是要了解胃幽門桿菌在新北市烏來區的盛行率並給予感染者抗生素除菌治療，另一個目的是想透過以家戶為單位的篩檢去了解家戶中的指標個案是否會影響其他家戶成員感染的風險。 方法：由於幽門桿菌感染具有人傳人模式，本次研究特別用家戶為單位的篩檢模式。對象為烏來地區年紀滿十六歲以上的居民，我們是用碳13尿素呼氣法來了解參加者的感染狀況。在108年的前導研究我們先在衛生所門診、巡迴醫療和教會禮拜時隨機收案，在這次前導研究的個案會把當作其家戶的指標個案。之後我們便會邀請指標個案的家戶內成員參與篩檢，同時我們也會完成家族樹和問卷的調查。最後我們用廣義估計方程式來量化陽性指標個案家戶成員和陰性指標個案家戶成員得到胃幽門桿菌感染的風險。 結果：從民國108年8月到民國109年7月止，我們共收集了340個案，其中274位個案來自72個家戶。340個案中有215個被檢測為幽門桿菌陽性，比例為63%。在檢測陽性與陰性個案間，無論是在性別、年齡、教育程度、生活型態和相關家族史上都沒有統計學上的差異。這七十二家戶的指標個案檢測陽性為48位陰性的為24位，其他176家戶成員檢測為陽性有111位檢測為陰性有63位，陽性指標個案家戶成員和陰性指標個案家戶成員的感染率分別是68%和53%，陽性指標個案家戶成員相較於陰性指標個案的勝算比為1.89。在調整過年齡、性別和抽菸行為後，迴歸分析結果我們看到陽性指標個案的家戶成員得到感染的機會是陰性指標個案的近二倍(勝算比：1.98，95%信賴區間：1.03-3.8)。 結論：在這次以家戶單位的社區篩檢，我們除了證明胃幽門桿菌的感染存在家戶聚集的特性，我們也發現一個家戶指標個案如果檢測結果為陽性，其家戶成員得到感染的風險是陰性指標個案家戶的二倍。本研究在一個幽門桿菌高盛行率的社區，創新發展了一個指標個案篩檢策略，在有限資源的情境下，能夠有效分配資源以提高篩檢效率。

Background: Helicobacter pylori (H. pylori) is a prevalent pathogen in Taiwanese communities, especially in the rural areas. It is the main cause of gastric cancer, among 90% of which are attributed to H. pylori infection. The inflammatory process triggered by H. pylori is continuous with time and severe consequence is possible; however, most of the H. pylori carriers are asymptomatic. H. pylori infection is positively associated with the lower socioeconomic status, poor living conditions, such as higher density of households and higher number of siblings, poor personal hygiene, and the lower availability of tap water. A previous community-based study in Taiwan demonstrated a very high H. pylori prevalence rate of 60% in the aboriginal regions. According to the data from Ministry of Health and Welfare in Taiwan, gastric cancer incidence (24.4 vs. 12.3 per 100,000 person-years) and mortality rates (15.8 vs. 6.8 per 100,000 person-years) were also higher in Indigenous peoples than in those of non-Indigenous, with 2.19-fold (95% CI: 2.06-2.33) and 2.47-fold (2.28-2.67) increased risk, respectively. Purpose: To test whether there was the phenomenon of family clustering of H. pylori infection in Wulai District (New Taipei City) and to develop a novel approach to identify the H. pylori carriers through a novel index case method. Methods: Owing to the importance of the person-to-person transmission of H. pylori, mass screening using the family as the unit was implemented. Residents aged 16 years and more were recruited for H. Pylori screening by using the C13-urea breath test (UBT). The screening service was delivered either at the outpatient clinic setting or during the Church worship meeting. The first group of participants was defined as the index cases; accordingly, we then invited their family members to receive the C13-UBT. The pedigrees of these family units were collected and their infection status was determined. We used the generalized estimating equation (GEE) to quantify the risk of H. pylori infection between the family members of the positive index cases and the negative index cases, adjusted for age, sex, and smoking. Results: During the period from August 2019 to July 2020, a total of 340 participants were enrolled in this study; among them, 72 families were identified in 274 participants; their infection-pedigree relationships were established. The positivity rate of C13-UBT was 63% (215 positive results over 340 participants). Between the test positives and negatives, these was no significant difference in the age, education level, sex, life style, and the family history of H. pylori infection, peptic ulcer, or gastric cancer. There were 48 and 24 participants defined as the positive and negative index cases, respectively; there were 111 and 63 family members for the positive and negative index cases, respectively. The H. pylori infection rates were 68% and 53%, respectively, for the positive index case families and the negative index case families. The odds ratio is 1.89. The analyses based on GEE showed a significantly increased risk of nearly two folds for the family members of positive index cases (adjusted odds ratio: 1.98, 95% CI: 1.03-3.8) as compared with those of the negative index cases, adjusted for age, sex, and smoking habit. Conclusions: In this mass screening program, we identified the phenomenon of familial aggregation of H. pylori infection. In addition, we found that, in the index cases tested positive for H. pylori, their family members also carried a higher risk of H. pylori infection when compared with the family members identified based on the negative index cases. Collectively, we demonstrate the effectiveness of using this novel index case method to identify the subjects with a higher prevalence rate of H. pylori infection. The results provide important implications on how to efficiently allocate the limited resources for mass screening and eradication of H. pylori in the remote areas. Keyword: H. pylori, Gastric cancer, Gastric cancer prevention, C13-urea breath test, familial aggregation.