Risk Factors for Hepatitis C in People with Unknown Transmission Routes

By Liz Highleyman

While it is well established that certain risk factors - in particular shared use of injection drug equipment - are associated with hepatitis C virus (HCV) infection, a significant proportion of hepatitis C patients (20%-40%) have no identified route of transmission.

As described in the November 2006 Journal of Viral Hepatitis, French researchers conducted a multicenter case-control study to investigate potential routes of HCV transmission in patients with no recognized parenteral risk factors.

The study included 450 HCV seropositive patients with no history of blood transfusion or injection drug use and 757 control subjects recruited from the general population and matched for sex, age, place of residence, and number of chronic diseases; 80% of cases had chronic hepatitis or cirrhosis, and 65% had genotype 1 HCV. All participants completed an interviewer-administered questionnaire about potential HCV risk factors.

Results

Among the 66 items considered, multivariate analysis identified 15 independent risk factors for HCV infection:
- Nosocomial (in-patient medical procedures):

admission to a medical facility (OR 2.1);

digestive endoscopy (OR 1.9);

admission to a surgical ward (OR 1.7);

surgical abortion (OR 1.7).
- Out-patient treatments:

cutaneous ulcer or wound care (OR 10.1);

diathermy (OR 3.0);

gamma globulin administration (OR 1.7);

intravenous injections (OR = 1.7);

varicose vein sclerotherapy (OR 1.6);

acupuncture (OR 1.5);

intramuscular injections (OR 1.4).
- Lifestyle factors:

intranasal cocaine use (OR 4.5);

engaging in contact sports (OR 2.3);
beauty treatments (OR 2.0);
professional pedicure or manicure (OR 1.7).
These factors explained 73% of community-acquired HCV infections.

Conclusion

In conclusion, the authors wrote, "for patients with unexplained routes of HCV infection, our data incriminate previously unidentified risk factors (abortions, some dermatological procedures, outpatient injections, contact sports, beauty treatments, professional pedicure/manicure) and confirm those already recognized (hospitalization, digestive endoscopy, acupuncture and intranasal cocaine use)."

These results suggest that prevention education materials and programs should include a broader range of exposures and activities that may put individuals at risk for contracting HCV. They also emphasize the need for universal precautions and sterile procedures in medical settings.

12/12/06

Reference
M. Karmochkine, F Carrat, O Dos Santos, and others. A case-control study of risk factors for hepatitis C infection in patients with unexplained routes of infection. Journal of Viral Hepatitis 13(11): 775-782. November 2006.