Population-attributable estimates for risk factors associated with hepatitis B and C: Policy implications for Pakistan and other South Asian countries

Introduction: Reuse of contaminated syringes, high frequency of injections, tattooing and skin piercing have repeatedly been shown to be important and independent risk factors for the transmission of hepatitis B (HBV) and C (HCV) infections in South Asian countries. Estimation of population-attributable risks indicates the potential for hepatitis prevention if the exposure to certain modifiable factors can be eliminated. Methods: We estimated the population-attributable risks of various risk factors for transmission of HBV and HCV using data from a large, nationally representative survey conducted in 2007 across Pakistan, a country known to have a high prevalence of chronic viral hepatitis. Odds ratio estimates and observed prevalence of the risk factors were used for calculating PAR estimates. We also performed a systematic review of published studies that identify the prevalence of similar modifiable risk factors for HBV and HCV from other South Asian countries in order to define an overall prevention strategy for the region. Results: For HBV, a high frequency (>10) of therapeutic injections in the past 1 year had an attributable risk of 3.5 % (95 % CI 2.9-3.9), reuse of syringes had a 2.7 % risk (95 % CI 2.2-3.1), the practice of being shaved by a barber 2.1 % (95 % CI 1.7-2.6), sharing of smoking utensils 4.4 % (95 % CI 3.8-4.9) and ear/nose piercing 1.4 % (95 % CI 1.2-1.7). Population-attributable risks for HCV were as follows: high frequency of therapeutic injections in the past 1 year 11.3 % (95 % CI 10.5-11.7), reuse of syringes 6.2 % (95 % CI 6.1-6.9), practice of being shaved by a barber shop 7.9 % (95 % CI 7.1-8.2), sharing of smoking utensils 8.1 % (95 % CI 6.9-8.5), practice of ear/nose piercing among females 5.9 % (95 % CI 5.2-6.1) and tattooing 5 % (95 % CI 4.3-5.6). A systematic review showed that other South Asian countries share a number of common risk factors for the transmission of viral hepatitis. Conclusion: A substantial number of HBV and HCV infections in Pakistan and other South Asian countries can be prevented by key interventions targeted toward a few selected and modifiable risk factors. Hence, policies specifically targeted at key risk factors for HBV and HCV such as safe and rational use of injections prescribed by trained health-care providers are urgently needed for countries like Pakistan.