Intramuscular-injection-associated gluteal fibrotic contracture and hepatitis B virus infection among school children.

A case control study was carried out to determine the exposure factors of gluteal fibrotic contracture (GFC). Sixty two school children were taken as the case group and were matched for sex, age and village of residence with 62 of their classmates constituting the control group. It was found that all 62 members of the case group had received intramuscular (IM) injections at some time prior to the onset of GFC, while only 57 of the control group had received IM injections. This difference is a statistically significant (p = 0.029). Injection sites on both buttocks were higher in the case group than among the controls. The odds ratio for the prevalence of hepatitis B virus infection (HBV) in the case group as compared to the control group was 3.0 (95% CI 1.1-7.8). A trend correlation was found between the annual frequency of IM injection, GFC and HBV infection. We concluded that IM injections played an important role in GFC and added to the risk of HBV infection, because they had been administered by improperly sterilized reusable syringes in an area where both GFC and HBV infections were prevalent and IM injection was common.