Many HIV-positive women in Rwanda are infected with strains of human papilloma virus associated with a high risk of cervical cancer, investigators report in an article published in the online edition of the Journal of Infectious Diseases. Their study also showed that women with cancer-associated strains of human papilloma virus who had a low CD4 cell count were more likely to have cancerous or pre-cancerous cell changes in the cervix.
Over 80% of cases of cervical cancer occur in resource-limited settings. There is little information about the characteristics of women who are infected with human papilloma virus. Such information is needed if appropriate screening and prevention services are to be provided.
Rwanda experienced a genocidal conflict in 1994, meaning that there is little recent information on the prevalence of either HIV or cervical infection with human papilloma virus. Studies before 1994 showed that cervical cancer was the most common malignancy amongst Rwandan women, accounting for 22% of all cancers. Furthermore, research undertaken in 1992-93 found that 24% of HIV-positive women in Rwanda had pre-cancerous cervical lesions.
Investigators therefore undertook a study to determine the prevalence and type of human papilloma virus infection in HIV-positive and HIV-negative women in Rwanda. The research was also designed to identify the factors associated with a risk of human papilloma virus infection.
A total of 647 HIV-positive and 188 HIV-negative women from the Rwanda Women’s Interassociation Study and Assessment (RWISA) were included in the research. The women were recruited to the study in 2005. All were aged over 25 years and were present in Rwanda during the 1994 genocide. The HIV-positive women were antiretroviral-naive, although women were eligible for recruitment to the study if they had taken single-dose nevirapine to prevent mother-to-child HIV transmission. Blood tests and cervical samples were obtained and the women completed questionnaires to determine their risk factors for infection with human papilloma virus.
Regardless of age, the prevalence of human papilloma virus was higher in HIV-positive than HIV-negative women (25-34 years, 75% vs 29%; 35-44 years, 64% vs 7%; 45-54 years, 57% vs 13% [all p
Furthermore, HIV-positive women of all ages were also significantly more likely to be infected with strains of human papilloma virus associated with cervical cancer (25-34 years, 50% vs 15%; 35-44 years, 43% vs 7%; 45-54 years, 33% vs 5%; and 55 years and above, 13% vs. 0%, all p
The investigators then restricted their analyses to HIV-positive women. They found that women with a CD4 cell count below 200 cells/mm3 were significantly more likely to be infected with a strain of human papilloma virus, other than HPV-16, associated with cervical cancer (p = 0.004). Furthermore, women with a CD4 cell count below 200 cells/mm3 were more likely than women with a CD4 cell count above 350 cells/mm3 to be infected with multiple strains of human papilloma virus (48% vs 24%).
A large proportion of HIV-positive women with human papilloma virus infection had abnormal cervical cells.
Almost all (91%) women with a CD4 cell count below 200 cells/mm3 and abnormal cervical findings were infected with human papilloma virus. By contrast, 49% of women with a CD4 cell count above 350 cells/mm3 infected with human papilloma virus had normal cervical cytology. Similar trends were seen when the investigators restricted their analysis to cancer-associated strains of human papilloma virus.
Finally the investigators examined risk factors for infection with human papilloma virus. Compared to women with a CD4 cell count above 350 cells/mm3 those with a CD4 cell count below 200 cells/mm3 (OR, 4.0; 95% CI, 2.4-6.6) and between 201-349 cells/mm3 (OR, 1.8; 95% CI, 1.1-2.7) were more likely to have the infection. Eating meat every week, an indicator of greater wealth, was also identified as a risk factor, as was a history of two or more gynaecological infections (OR, 2.1; 95% CI, 1.4-3.2).
“HIV-seropositive Rwandan women in our study had high prevalences of infection with HPV (69%), carcinogenic HPV (46%), and multiple HPV types (35%), which in turn were associated with higher risks of abnormal cervical cytology findings”, write the investigators.
Women who had been raped were slightly less likely to have human papilloma virus infection. The investigators note that this finding may seem “counterintuitive” but write “our data indicate that many women who experienced genocidal rape over ten years before the study were subsequently abstinent or had very few partners, thus limiting their exposure to new HPV infections.”
The investigators conclude, “in the past decade, significant strides have been made in the prevention, detection, and treatment of cervical cancer. With ongoing research and commitment from global policy makers, such services can be provided to…highest-risk populations.” They are hopeful that the results of their study “will help guide cervical cancer prevention strategies in Rwanda”.
Singh DK et al. Human papillomavirus infection and cervical cytology in HIV-infected and HIV-uninfected Rwandan women. J Infect Dis 199: 1-9, 2009.