Human papillomavirus variants among Inuit women in northern Quebec, Canada

Abstract

BackgroundInuit communities in northern Quebec have high rates of human papillomavirus (HPV) infection, cervical cancer and cervical cancer–related mortality as compared to the Canadian population. HPV types can be further classified as intratypic variants based on the extent of homology in their nucleotide sequences. There is limited information on the distribution of intratypic variants in circumpolar areas.ObjectiveOur goal was to describe the HPV intratypic variants and associated baseline characteristics.DesignWe collected cervical cell samples in 2002–2006 from 676 Inuit women between the ages of 15 and 69 years in Nunavik. DNA isolates from high-risk HPVs were sequenced to determine the intratypic variant.ResultsThere were 149 women that were positive for HPVs 16, 18, 31, 33, 35, 45, 52, 56 or 58 during follow-up. There were 5 different HPV16 variants, all of European lineage, among the 57 women positive for this type. There were 8 different variants of HPV18 present and all were of European lineage (n=21). The majority of samples of HPV31 (n=52) were of lineage B. The number of isolates and diversity of the other HPV types was low. Age was the only covariate associated with HPV16 variant category.ConclusionsThese frequencies are similar to what was seen in another circumpolar region of Canada, although there appears to be less diversity as only European variants were detected. This study shows that most variants were clustered in one lineage for each HPV type.

Persistence of human papillomavirus 16, 18 and 52 variants in Inuit women from Northern Quebec, Canada

“…As HPV persistence and associated cervical cancer risk have been shown to be dependent on variant prevalence and ethnic origin [21] , the previous literature on other high-risk communities may not be generalisable to Nunavik. Previous research in this area showed that there is a low diversity of variants present in this population and all HPV16 and 18 variants were of European lineage (lineage A) [26] . Additionally, highrisk (HR) type HPV52 is relatively prevalent in this population [24,26].…”

“…Previous research in this area showed that there is a low diversity of variants present in this population and all HPV16 and 18 variants were of European lineage (lineage A) [26] . Additionally, highrisk (HR) type HPV52 is relatively prevalent in this population [24,26]. The literature on HPV polymorphism and risk of persistence and cancer has primarily focused on HPV16 and 18 as they are implicated in the majority of cervical cancer cases.…”

“…Other studies have shown that the same variant is detected in consecutive HPV-positive visits and have also found that co-infection with multiple variants is rare so this seemed to be a reasonable assumption [19,20,40]. Additionally, the same variant was detected for the subset of participants for whom multiple samples were tested for variant analysis (N = 30 total) [26] . Most reports categorise variants into phylogenetic lineages which was not feasible here for HPV16 and 18 due to high homogeneity of sequences in this cohort.…”

“…Most reports categorise variants into phylogenetic lineages which was not feasible here for HPV16 and 18 due to high homogeneity of sequences in this cohort. Variants were all in the same lineage and therefore sublineage comparisons were made instead [26] . The impact on cervical cancer and pre-cancer outcomes could not be assessed because of the small number of these outcomes (N = 16).…”

“…The HPV DNA typing and PCR-sequencing of the long control region (LCR) for variant testing was previously described [26] . The variant was assessed on the first positive specimen for HPV16, 18 or 52.…”