Hepatitis B and C seroprevalence in the Lebanese population

R. Baddoura,1 C. Haddad2 and M. Germanos3 

1Epidemiological Unit, Faculty of Medicine, Saint Joseph University, Beirut, Lebanon.
2Haematology Laboratory, Notre Dame des Secours Hospital, Byblos, Lebanon.
3Haematology Laboratory, Hôtel Dieu Hospital, Beirut, Lebanon.
 

الانتشار المصلي لكل من التهاب الكبد ((بي)) و((سي)) لدى اللبنانيين

رفيق بدورة، كريستيان حداد وميرنا جيرمانوس

الخلاصـة: لتقييم مدى التعرض لكل من التهاب الكبد  ((بي)) و((سي )) وعوامل الاختطار المحتملة بين اللبنانيين طلبنا من جميع المراجعين للوحدات المختبرية خلال فترة أسبوعين إعطاء 5 ميلي لتر من عينات الدم مع استكمال الاستبيان حول عوامل الاختطار، أما المراجعون الذين تقل أعمارهم عن 5 سنوات فقد أجريت مقابلات مع أمهاتهم، ثم حللت العينات المجموعة في نفس المختبر الذي جمعت فيه بالمقايسة المناعية بالإنزيم الدقيق الجزيئات. وبلغ مجموع العينات التي حللت 2893 عينة. وقد بلغ معدل رفض الاشتراك بالدراسة 2.9%، ومعدل التعرض لمستضدات التهاب الكبد 18.9% وكان الحَمَلة 1.9% ومعدل انتشار التهاب الكبد ((بي)) الحاد 0.1%، أما التعرض لمستضدات التهاب الكبد ((سي) فقد كان 0.7% فيما كان التعرض لكل من أضداد التهاب الكبد ((سي)) وأضداد التهاب الكبد اللبِّية معاً 0.2% ويزداد معدل انتشار أضداد التهاب الكبد اللبِّية بتقدم العمر فكانت أعلى ما تكون لدى الرجال. ومن أهم عوامل الاختطار نقل الدم والديال الدموي وتنظير الجهاز الهضمي.

ABSTRACT We aimed to evaluate exposure to hepatitis B and C viruses (HBV and HBC) and candidate risk factors among the Lebanese population. All individuals presenting to all laboratory units in the country over a 2-week period were asked for a 5-mL whole blood sample and answered a questionnaire addressing risk factors. For individuals under 15 years of age the mother was interviewed. In all, 2893 blood samples were examined. Refusal rate was 2.9%. Exposure to HBV antigen was 18.9%; 1.9% were carriers and acute hepatitis B point prevalence was 0.1%. Exposure to HCV antigen was 0.7%. Exposure to both HBc and HCV antibodies was 0.2%. HBc prevalence increased with age and was higher among men. Significant risk factors included blood transfusion, haemodialysis and gastrointestinal endoscopy.

La séroprévalence des hépatites B et C dans la population libanaise

RESUME Notre objectif était d'évaluer l'exposition aux virus de l'hépatite B et de l'hépatite C (VHB et VHC) et les facteurs de risque potentiels dans la population libanaise. Il a été demandé à tous les individus se présentant dans des services de laboratoire dans le pays sur une période de deux semaines de se prêter à un prélèvement de 5 ml de sang total et de répondre à un questionnaire concernant les facteurs de risque. Pour les individus âgés de moins de 15 ans, c'est la mère qui était interrogée. En tout, 2893 échantillons sanguins ont été examinés. Le taux de refus s'élevait à 2,9 %. L'exposition à l'antigène du virus de l'hépatite B était de 18,9 % ; 1,9 % étaient des porteurs et la prévalence instantanée de l'hépatite B aiguë était de 0,1 %. L'exposition à l'antigène du virus de l'hépatite C était de 0,7 %. L'exposition simultanée aux anticorps anti-HBc et anti-VHC était de 0,2 %. La prévalence des anticorps anti-HBc augmentait avec l'âge et était supérieure chez les hommes. Les facteurs de risque significatifs comprenaient la transfusion sanguine, l'hémodialyse et l'endoscopie gastrointestinale.

Introduction

Hepatitis B and C are of increasing concern to public health authorities in the deve­loping world where universal vaccination campaigns are being considered [1–5]. In the Middle East there is a need for further public health surveys to assess the situation [6–9].

In Lebanon, following the World Health Organization recommendations, the Minis­try of Health is considering implementing a hepatitis B vaccination programme. The country is administratively divided into five districts: Beirut the capital, Mount Lebanon the central part, the North, the South and the Bekaa plateau on the eastern side. Current data on hepatitis B and C in Lebanon are limited to population sub­groups, namely blood donors, prisoners, pregnant women and health professionals [10–15].

The aim of our study was to estimate hepatitis B and C seroprevalence in the whole Lebanese population and to evaluate candidate risk factors as reported in the literature.

Methods

This was a cross-sectional population­-based national survey run over a 2-week period through medical laboratory facilities. The study included blood-sampling units of both public and private institutions dist­ributed throughout the different administ­rative departments in the country. After informed consent, all individuals presenting to these blood-sampling units over a 2-week period for whatever medical reason were included. They were asked for a 5-mL whole blood sample for hepatitis B and C assays and were questioned through direct interview about candidate risk fac­tors for hepatitis B and C. For those under the age of 15 years, the mother was inter­viewed.

Each participant was asked about expo­sure to any of the following risk factors: blood transfusion, intramuscular or intra­venous injection, minor or major surgery, laparoscopy, local or general anaesthesia, dental or gum care, endoscopy, haemo­dialysis or peritoneal dialysis, personal or family history of hepatitis. Women were also asked about any previous caesarean section and curettage. Sociodemographic variables included marital and professional status, and nationality. In addition, indi­viduals were asked about previous hepatitis B vaccination.

Sera were stored at –20 °C until tested. All samples were analysed in the same laboratory unit using microparticle enzyme immunoassay (AxSYM CORE) (Abbott Laboratories) [16]. Samples were first tested for the presence of antibodies to hepatitis B core antigen (anti-HBc). When­ever positive, hepatitis B surface antigen (HbsAg) and hepatitis B surface antibodies were tested. A confirmatory AxSYM assay was carried out for the confirmation of samples found to be reactive to HBsAg. Antibodies against HCV (anti-HCV) were also assayed by a microparticle enzyme immunoassay; when reactive, additional confirmation was performed using a Wes­tern blot assay (Genelabs Diagnostics).

Data entry and analysis were performed using Epi-Info and STATA software. Esti­mates are given with their 95% confidence interval (CI). Risk factors were evaluated as part of a logistic regression model with exposure to hepatitis virus as the dependent variable.

Results

In the 2-week period, 2982 individuals were recruited, from which 2893 blood samples were examined. Refusal rate was 2.9%. Age and gender characteristics com­pared to the whole population are sum­marized in Table 1.
Table 1 Distribution of the sample and population by age, sex and district

 Exposure to hepatitis B antigen as indicated by positive HBc anti­body seroprevalence was 18.9% (95% CI: 17.4–20.2); 1.9% were carriers and acute hepatitis B point prevalence was 0.1%. Exposure to hepatitis C antigen as indicated by positive HCV antibody seroprevalence was 0.7% (95% CI: 0.4–1.0) (Table 2). Exposure to both HBV and HCV was 0.2% (95% CI: 0.1–0.3). Anti-HBc prevalence increased with age and was higher among males (21.4%) than females (16.9%) while anti-HCV prevalence showed no signi­ficant age or sex differences.

Table 2 Seroprevalence of hepatitis B and C markers

The total number of immigrants was 103 (3.5%). When we excluded these individuals to adjust for the population demographic structure, the actual seropre­valence figures for anti-HBc, anti-HBs and HBsAg were not significantly changed (Table 2).

As regards hepatitis B vaccination, 222 (7.7%) individuals had been vaccinated. When we excluded these individuals, sero­prevalence figures for anti-HBc, anti-HBs and HBsAg were not significantly changed (Table 2).

Taking into account the differences in age distribution of our sample and that of the general population, we calculated the expected seroprevalence for hepatitis B and C adjusted for age. In this case, hepatitis B exposure would be expected to be 14.0% versus the observed 18.2%, while hepatitis C exposure would remain almost the same with 0.7% expected versus 0.6% as ob­served (Table 3).

Table 3 Observed versus expected seroprevalence of anti-HBc and anti-HCV after adjusting for age

Exposure to hepatitis B antigen was higher among the inhabitants from the South, married people and immigrants (Table 4). There were no significant dif­ferences for hepatitis C exposure with respect to any of these characteristics, but in general the figures were low.

Table 4 Anti-HBc positivity by sociodemographic characteristic (n = 2982)

Risk factors that were significantly associated with hepatitis B antigen expo­sure, adjusted for age and sex, included blood transfusion (OR = 1.38, 95% CI: 1.05–1.80), haemodialysis (OR = 3.09, 95% CI: 1.29–7.36) and gastrointestinal endoscopy (OR = 1.44, 95% CI: 1.09–1.90). After adjusting for each risk factor using a logistic regression model, all three factors remained significantly associated with exposure to hepatitis B antigen (Table 5). Risk factors for HCV exposure adjus­ting for age and sex were limited to haemo­dialysis (OR = 25.91, 95% CI: 6.62–101.5) and blood transfusion. Adjusting for each risk factor using a logistic regression mo­del, only haemodialysis remained a risk factor (Table 6).

Table 5 Age- and sex-adjusted odds ratios of risk factors for presence of hepatitis B virus core antigen antibodies

Table 6 Age- and sex-adjusted odds ratios of risk factors for presence of hepatitis C virus antibodies

Discussion

The estimated population-based anti-HBc prevalence was 18.9% (CI: 17.4–20.2). The figure is close to what has been repor­ted in other developing and Mediterranean countries [2,3,6,16]. A 1.9% point preva­lence of positive HBsAg is similar to prev­iously reported data on blood donors in Lebanon [15]. Our figure is also close to that reported in France in 1995 [17]. Similarly, the 0.7% anti-HCV prevalence we observe in our population falls within the range of 0.5%–1.7% reported in Medi­terranean countries [6,8,9,17]. Therefore, hepatitis B and C in Lebanon are as much public health issues as in neighbouring countries.

Our sample can be considered quite representative of the Lebanese population regarding sex and district distributions (Table1). The geographical distribution of our sample matched that of the general population taking into consideration the differences in administrative frames used by the Order of Medical Laboratories and the Public Administration respectively. However, people over 25 years of age were overrepresented while children under 15 years were underrepresented in our sam­ple. Immigrants were also under-repre­sented, but they are not included in the population census estimates [18]. Never­theless, for extrapolation of the data from our sample to the whole population we used the standardization method.

Self-reported reasons for blood samp­ling included medical prescription (50.1%), screening (44.7%), pregnancy examination (3.7%), premarital check-up (1.4%) and hepatitis B vaccine assessment (0.1%). The number of individuals reporting past history of hepatitis or jaundice was 236 (8.2%). Self-reported reasons for blood sampling reflect the pattern of use of health care facilities and we have no reason to believe they are related to hepatitis antigen status. Actually, there was no statistically significant association between self-repor­ted past history of hepatitis and hepatitis antigen status.

At the national level, our sample selec­tion technique was feasible and acceptable. Obtaining blood samples from a random sample of the general population is a dif­ficult task and would probably result in a significant refusal rate and biased esti­mates. Because of cost and logistic cons­traints, most “population-based” surveys are limited to small geographical areas or population subgroups within specific set­tings.

Our study is the first population-based survey on hepatitis in Lebanon and it fol­lows a method easy to repeat if we were to assess the impact of any future public health intervention on hepatitis B and C.

As for risk factors, our results are in agreement with the medical literature [19–21]. Blood transfusion [22] and haemo­dialysis [23] were the major risk factors for both hepatitis B and C antigen transmis­sion. Blood transfusion or haemodialysis expose individuals to hepatitis C more than hepatitis B. A 25.8% prevalence of anti­HCV among individuals who have under­gone haemodialysis has been reported by Naaman and al. [15]. Gastrointestinal endo­scopy is a serious nosocomial risk factor for hepatitis B infection since it is a com­monly prescribed procedure, and aware­ness about hospital hygiene control is needed among health professionals.

Whether a universal vaccination prog­ramme against hepatitis B is a must remains debatable. However, a vaccination policy is required for at-risk population subgroups. Blood transfusion quality control must be implemented [24].

Acknowledgements

The authors thank the Ministry of Health, Abbots Laboratories and the Lebanese Epidemiological Association.

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