Indian women with higher serum concentrations of folate and vitamin B12 are significantly less likely to be infected with carcinogenic or high-risk (HR) types of human papillomaviruses (HPVs)

BACKGROUND: Studies conducted in the USA have demonstrated that micronutrients such as folate and vitamin B12 play a significant role in modifying the natural history of high-risk human papillomaviruses (HR-HPVs), the causative agent for developing invasive cervical cancer (CC) and its precursor lesions. OBJECTIVE: The purpose of the current study was to investigate whether these micronutrients have similar effects on HR-HPV infections in Indian women. METHODS: The associations between serum concentrations of folate and vitamin B12 and HR-HPV infections were evaluated in 724 women who participated in a CC screening study in the southern state of Andhra Pradesh, India. Serum folate and vitamin B12 concentrations were measured by using a competitive radio-binding assay. Digene hybrid capture 2 (HC2) assay results were used to categorize women into two groups, positive or negative for HR-HPVs. Unconditional logistic regression models specified a binary indicator of HC2 (positive/negative) as the dependent variable and serum folate concentrations combined with serum vitamin B12 concentrations as the independent predictor of primary interest. Models were fitted, adjusting for age, education, marital status, parity, type of fuel used for cooking and smoking status. RESULTS: Women with higher concentrations of serum folate (>6 ng/mL) and vitamin B12 (>356 pg/mL) were at lower risk of being positive for HR-HPVs compared to those with serum folate ≤6 ng/mL and serum vitamin B12 ≤ 356 pg/mL (odds ratio = 0.26; 95% confidence interval: 0.08-0.89; P = 0.03). CONCLUSIONS: These results demonstrated that improving folate and vitamin B12 status in Indian women may have a beneficial impact on the prevention of CC. Micronutrient based interventions for control of HR-HPV infections may represent feasible alternatives to vaccine based approaches to HPV disease prevention, which are currently unaffordable for use in resource limited areas in rural India

Effectiveness of VIA, Pap, and HPV DNA Testing in a Cervical Cancer Screening Program in a Peri-Urban Community in Andhra Pradesh, India

BACKGROUND: While many studies have compared the efficacy of Pap cytology, visual inspection with acetic acid (VIA) and human papillomavirus (HPV) DNA assays for the detection cervical intraepithelial neoplasia and cancer, few have evaluated the program effectiveness. METHODS AND FINDINGS: A population-based sample of 5603 women from Medchal Mandal in Andhra Pradesh, India were invited to participate in a study comparing Pap cytology, VIA, and HPV DNA screening for the detection of CIN3+. Participation in primary screening and all subsequent follow-up visits was rigorously tracked. A 20% random sample of all women screened, in addition to all women with a positive screening test result underwent colposcopy with directed biopsy for final diagnosis. Sensitivity, specificity, positive and negative predictive values were adjusted for verification bias. HPV testing had a higher sensitivity (100%) and specificity (90.6%) compared to Pap cytology (sensitivity  =  78.2%; specificity = 86.0%) and VIA (sensitivity = 31.6%; specificity = 87.5%). Since 58% of the sample refused involvement and another 28% refused colposcopy or biopsy, we estimated that potentially 87.6% of the total underlying cases of CIN3 and cancer may have been missed due to program failures. CONCLUSIONS: We conclude that despite our use of available resources, infrastructure, and guidelines for cervical cancer screening implementation in resource limited areas, community participation and non-compliance remain the major obstacles to successful reduction in cervical cancer mortality in this Indian population. HPV DNA testing was both more sensitive and specific than Pap cytology and VIA. The use of a less invasive and more user-friendly primary screening strategy (such as self-collected swabs for HPV DNA testing) may be required to achieve the coverage necessary for effective reduction in cervical cancer mortality

Suitability of self-collected vaginal samples for cervical cancer screening in periurban villages in Andhra Pradesh, India.

OBJECTIVES: Our aim was to determine if (1) Hybrid Capture 2 and a PCR-based method were comparable for detection of high-risk human papillomavirus (HPV) clinician-collected and self-collected samples were equally efficient to detect HPV and cervical cancer precursor lesions, and (3) if participation rates improved with home-based versus clinic-based self collection. METHODS: Samples were selected from women participating in a cervical cancer screening study according to HPV, visual inspection with acetic acid, or Pap smear screening results. From 432 of 892 selected women, split sample aliquots were tested for HPV DNA using both the Hybrid Capture 2 assay and the Roche prototype line blot assay. Women from a subset of villages were recruited at two separate time points for clinic-based self-collection and home-based self-collection, and participation rates were compared. RESULTS: Pairwise agreement between self- and clinician-collected samples was high by both Hybrid Capture 2 (90.8% agreement, kappa = 0.7) and PCR (92.6% agreement, kappa = 0.8), with significantly increased high-risk HPV detection in clinician-collected specimens (McNemar's P < 0.01). Ability to detect precursor lesions was highest by PCR testing of clinician-collected samples and lowest by Hybrid Capture 2 testing of self-collected samples (11 of 11 and 9 of 11 cases of cervical intraepithelial neoplasia grade 2/3 and cancer detected, respectively). Participation in home-based screening was significantly higher than clinic-based screening (71.5% and 53.8%, respectively; P < 0.001) among women ages 30 to 45 years. CONCLUSION: The combination of improved screening coverage and a high single test sensitivity afforded by HPV DNA testing of home-based self-collected swabs may have a greater programmatic effect on cervical cancer mortality reduction compared with programs requiring a pelvic exam

Demographics of study population.

<p>Demographics of study population.</p

Estimated proportion of cases of CIN2+ observed and estimated via population weighting for verification bias adjustment.

<p><i>Screen detected</i> indicates proportion of cases of CIN2+ detected by hc2, and <i>screen undetected</i> indicates the proportion of CIN2+ cases detected through the screening program, but missed by hc2. <i>Refused biopsy</i> indicates the proportion of CIN2+ cases estimated among those who refused biopsy, <i>refused colposcopy</i> indicates the proportion of CIN2+ cases estimated among those who screened positive, but refused colposcopic exam, and <i>refused involvement</i> indicates the proportion of CIN2+ cases estimated among those who refused participation in the program (i.e., not screened).</p

Test performance characteristics.

<p>A. Crude estimates among women with full colposcopic and histologic evaluation (N = 675). B. Verification-biased adjusted estimates among total screened population (N = 2331).</p><p>CIN: cervical intraepithelial neoplasia, CI: confidence interval, PPV: positive predictive value, NPV: negative predictive value</p

Participation in screening and follow-up (colposcopy and biopsy where recommended) by randomization arm and screening result.

<p>Screen positive indicates positive result on VIA, Pap, and/or HPV DNA testing. Colposcopy normal indicates no area of abnormality identified, no biopsy recommended. Colposcopy abnormal-biopsy taken indicates that a biopsy was successfully obtained from all visually identified areas of abnormality. Colposcopically abnormal-biopsy refused indicates that a lesion was visualized and biopsy recommended, but the patient refused.</p