HPV genotypes have distinct distributions among various ethnic populations worldwide. In December 2013, 237 and 159 cervical samples were collected from Hani and Han ethnic women, respectively, in Mojiang, a rural county in southern Yunnan. The overall HPV infection rate (21.1%) among the Hani women was significantly higher than that among the Han women (12.6%). The high-risk (HR) and low-risk (LR) HPV and single- and multiple-genotype infection rates among the Hani women were 11.0%, 4.6%, 15.6%, and 5.5%, respectively. HPV-16 (3.8%) was the most prevalent genotype among the Hani women, followed by HPV-52 (1.7%), HPV-31 (0.8%), and HPV-33 (0.8%). Comparatively, the Han women had lower infection rates of high-risk (8.2%), low-risk (1.2%), single-genotype (9.4%), and multiple-genotype HPV infections (3.1%). HPV-16 (3.1%) was also the predominant genotype among the Han women, followed by HPV-52 (1.3%), HPV-33 (0.6%), HPV-44 (0.6%), and HPV-54 (0.6%). The area background, number of children, and past history of STIs were recognized as potential risk factors for HPV infection. Rural background, age, education level, number of children, and illness history were significantly associated with HPV infection among the Hani women. These findings highlight the urgent need for HPV prevention and control strategies in Yunnan, particularly for the Hani ethnic women.
Human papillomavirus (HPV) is one of the most common sexually transmitted pathogens of the genital system and plays a vital role in the development of cervical cancer [
Epidemiologically, the HPV prevalence rates and genotype distributions vary among different geographical regions. The highest HPV prevalence in women without cervical abnormalities has been reported in Africa (24%), followed by Eastern Europe (21%), Latin America (16%), and Southeast Asia (14%) [
Cervical cancer cases are increasing in China, and due to distinct topographical variations, HPV prevalence varies among different regions of China [
Hani group is a Chinese certified ethnic minority group that mainly inhabits southeast China [
In June and July of 2014, this cross-sectional study was collaboratively conducted at Mojiang by the Department of Gynaecology, the First People’s Hospital of Yunnan Province, and Kunming University of Science and Technology. Interested women were requested to visit a local hospital in Mojiang County, Yunnan, and written consent was obtained. A standardized questionnaire was used to collect information about ethnic background, age, education, marital status, illness history, sexual activity, and profession. After completion of the questionnaire, a qualified gynaecologist performed pelvic examination and sample collection. Women who met the following criteria were recruited into the current study: those who (a) were not a gynaecological outpatient with symptoms related to genital tract disease (commonly cervicitis and/or vulvar discomfort); (b) were not currently pregnant; and (c) had not undergone a total uterus or cervical resection. Finally, a total of 396 participants from general population, including 237 Hani and 159 Han women, were considered qualified and were recruited for this study. The protocol was followed in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of Kunming University of Science and Technology and the Center for Disease Control and Prevention (CDC) in Yunnan Province, China.
A qualified gynaecologist collected exfoliated cervical cells from each participant using a cytobrush (Hybribio). Each sample of exfoliated cervical cells was inserted into a vial with preservation solution (Hybribio, Chaozhou, China) and vigorously swirled 10 times. The vial contents were sent to Yunnan First People’s Hospital for cytological analysis. All cytological slides were individually prepared by two qualified technicians. All of the cytology specimens were classified according to the Bethesda classification system [
Cervical samples were collected with a cervix brush, and cells were placed into a vial containing preserving media. The samples were transported at −20°C to a central laboratory. A QIAamp DNA Mini Kit (Qiagen, Valencia, CA, USA) was used to extract DNA from the cervical samples according to the manufacturer’s instructions.
PCR amplification of the housekeeping
HPV genotypes were determined using an HPV GenoArray Test Kit (Hybribio, Chaozhou, China) according to the manufacturer’s instructions. The GenoArray test is an L1 consensus primer-based PCR assay that is capable of amplifying 21 HPV genotypes, including 15 HR-HPV genotypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, and 68) and 6 low-risk HPV genotypes (LR-HPV) (6, 11, 42, 43, 44, and CP8304) [
The HPV prevalence rates, including the total rates, and the rates for single- and multiple-genotype infections, were compared using the Chi-square test. Corresponding 95% confidence intervals (CIs) were estimated by binomial distribution analysis. The effects of age-related variables on HPV infection in women were assessed using the logistic regression model, with the grouping of age in 10-year intervals (<35, 36–45, and <46), and odds ratios and their 95% CIs were calculated. Possible risk factors for HPV infection acquisition were evaluated by univariate analysis and multivariate logistic regression analyses, and odds ratios and their 95% CIs were calculated. A
Among the 396 recruited women, 70 were found to be HPV DNA positive (17.7%, 70/396). Of them, 52 (13.1%) were positive for an HPV single-genotype infection, while 18 (4.5%) had a multiple-genotype infection. A total of 23 genotypes were identified, with the most frequently detected HR-HPV genotypes being HPV-16 (14/396, 3.5%), HPV-52 (6/396, 1.5%), HPV-33 (3/396, 0.8%), HPV-58 (2/396, 0.5%), and HPV-18 (2/396, 0.5%). Comparatively, the most common low-risk HPV genotypes were HPV-54 (3/398, 0.8%), HPV-11 (3/396, 0.8%), HPV-55 (2/396, 0.5%), and HPV-42 (2/396, 0.5%). The prevalence of HR-HPV (9.8%, 39/396) was significantly higher than that of low-risk human papillomavirus (LR-HPV) (3.3%, 13/396), with a
The prevalence of HPV and genotypes distribution among Hani and Han ethnic women.
Variables | Total ( |
Hani ( |
Han ( |
| |||
---|---|---|---|---|---|---|---|
Positive | P% (95% CI) |
Positive | P% (95% CI) |
Positive | P% (95% CI) | ||
Age |
|
|
|
0.76 | |||
Prevalence | 70 | 17.68 (13.93–21.44) | 50 | 21.1 (15.91–26.29) | 20 | 12.6 (7.45–17.75) |
|
Single infection | 52 | 13.13 (9.8–16.46) | 38 | 15.6 (11.4–20.22) | 14 | 9.4 (5.06–14.14) |
|
High risk | 38 | 9.6 (6.7–12.5) | 26 | 11 (7.01–14.98) | 13 | 8.2 (4.94–12.46) | 0.39 |
HPV-16 | 14 | 3.53 (1.71–5.35) | 9 | 3.8 (2.56–5.04) | 5 | 3.1 (0.41–6.09) | 0.73 |
HPV-52 | 6 | 1.51 (0.31–2.71) | 4 | 1.69 (0.06–3.34) | 2 | 1.3 | 1.000 |
HPV-68 | 2 | 0.50 | 1 | 0.42 | 1 | 0.63 | 1.000 |
HPV-33 | 3 | 0.76 | 2 | 0.84 | 1 | 0.63 | 1.000 |
HPV-31 | 2 | 0.50 | 2 | 0.84 | 0 | — | — |
HPV-18 | 2 | 0.50 | 1 | 0.42 | 1 | 0.63 | 1.000 |
HPV-58 | 2 | 0.50 | 1 | 0.42 | 1 | 0.63 | 1.000 |
HPV-35 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-59 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-53 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-51 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-56 | 2 | 0.50 | 1 | 0.42 | 1 | 0.63 | 1.000 |
HPV-66 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-83 | 1 | 0.25 | 0 | — | 1 | 0.63 | — |
Low risk | 14 | 3.53 (1.71–5.35) | 11 | 4.6 (1.93–7.27) | 2 | 1.26 (0.47–2.99) | 0.084 |
HPV-54 | 3 | 0.76 | 2 | 0.84 | 1 | 0.63 | 1.000 |
HPV-55 | 2 | 0.50 | 2 | 0.84 | 0 | — | — |
HPV-11 | 3 | 0.76 | 3 | 1.26 | 0 | — | — |
HPV-42 | 2 | 0.50 | 2 | 0.84 | 0 | — | — |
HPV-40 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-43 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-44 | 1 | 0.25 | 0 | — | 1 | 0.63 | — |
Multiple infection | 18 | 4.54 (2.49–6.59) | 13 | 5.5 (2.6–8.4) | 5 | 3.2 (0.47–5.93) | 0.33 |
Double infection | 14 | 3.53 (1.71–5.35) | 10 | 4.2 (1.65–6.75) | 4 | 2.5 (0.08–4.93) | 0.42 |
High risk | 8 | 2.02 (0.64–3.4) | 5 | 2.1 (0.28–3.92) | 3 | 1.9 (0.81–2.99) | 1.000 |
HPV-16/58 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-16/52 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-39/68 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-52/58 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-18/68 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-16/33 | 1 | 0.25 | 0 | — | 1 | 0.63 | — |
HPV-18/58 | 1 | 0.25 | 0 | — | 1 | 0.63 | — |
HPV-52/66 | 1 | 0.25 | 0 | — | 1 | 0.63 | — |
Mixed infection | 5 | 1.26 (0.16–2.36) | 4 | 1.7 (0.06–3.34) | 1 | 0.63 (−0.6–1.86) | 0.65 |
HPV-56/43 | 1 | 0.25 | 0 | — | 1 | 0.63 | — |
HPV-58/6 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-52/6 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-52/43 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-51/54 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
Low risk | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-54/55 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
Triple infection | 4 | 1.01 (0.03–1.99) | 3 | 1.3 (0.014–2.74) | 1 | 0.63 (−0.6–1.86) | 0.65 |
High risk | 2 | 0.50 | 1 | 0.42 | 1 | 0.63 (−0.6–1.86) | |
HPV-33/35/58 | 1 | 0.25 | 1 | 0.42 | 0 | — | — |
HPV-16/31/52 | 1 | 0.25 | 0 | — | 1 | 0.63 | — |
Mixed infection | 2 | 0.50 | 2 | 0.84 | 0 | — | — |
|
|||||||
|
1 | 0.25 | 1 | 0.42 | 0 | — | — |
Coinfection of multiple HPV genotypes did not occur frequently. In total, 4.5% (18/396) of the patients had a multiple-genotype HPV infection. Of them, 3.5% (14/396) had a double infection (HPV-16/52, HPV-52/6, and HPV-54/55), 0.8% (3/396) had a triple infection (HPV-33/35/58, HPV-16/31/52, and HPV-16/58/44), and only 0.2% were found to be infected with four genotypes (HPV-16/33/11/40) (Table
Among the 237 recruited Hani women, 50 (50/237, 21.1%) were found to be HPV DNA positive. In contrast, HPV DNA was detected in only 12.6% (20/159) of the Han women. The HPV prevalence observed among the Hani women (21.1%) was significantly higher than that among the Han women (12.6%), with a
A total of 23 HPV genotypes were identified in this study (Figure
Human papillomavirus genotype-specific distribution (Yunnan, China, 2015).
The mean age of the 396 recruited women was 41.58, with a range of 18 to 74 years (SD = 7.5 years, 95% CI, 40.92–42.41) and median of 41 years. There was no significant age difference between the Hani (41.53 years (median = 41), SD = 8.79, 95% CI, 40.41–42.66) and Han ethnic groups (41.86 years (median = 41), SD = 4.99, 95% CI, 41.08–42.64) (
Comparison of the age-specific overall, high-risk, single, and multiple HPV infection prevalence in three age groups among the Hani and Han women.
Age |
|
Overall | OR 95% CI |
|
HR |
OR 95% CI |
|
Single | OR 95% CI |
|
Multiple | OR 95% CI |
|
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Hani | |||||||||||||
|
65 | 15 | 1 | 0.89 | 8 | 1 | 0.88 | 11 | 1 | 0.64 | 5 | 1 | 0.47 |
|
92 | 19 | 0.9 (0.4–1.9) | 9 | 0.8 (0.3–2.1) | 16 | 1.1 (0.4–2.4) | 3 | 0.4 (0.1–0.8) | ||||
|
80 | 16 | 0.8 (0.4–1.8) | 9 | 0.9 (0.3–2.5) | 10 | 0.7 (0.3–1.8) | 5 | 0.8 (0.2–2.9) | ||||
|
|||||||||||||
Han | |||||||||||||
|
9 | 3 | 1 | 0.14 | 2 | 1 | 0.22 | 3 | 1 |
|
1 | 1 | 0.42 |
|
120 | 15 | 0.3 (0.06–1.3) | 9 | 0.3 (0.05–1.6) | 10 | 0.2 (0.03–0.8) | 3 | 0.2 (0.02–2.2) | ||||
|
30 | 2 | 0.1 (0.02–1.0) | 1 | 0.1 (0.01–1.5) | 2 | 0.1 (0.01–1.0) | 1 | 0.3 (0.01–4.9) |
Age-specific prevalence of human papillomavirus DNA and corresponding 95% confidence interval (Hani, Yunnan, China, 2015).
Multivariate logistic regression analysis was applied to determine the roles of various possible risk factors in the acquisition of HPV infection. Marital status and extra sexual partners were not found to significantly contribute to the development of HPV infection for either group of participants. Notably, we cannot draw any conclusions about the role of sexual activity in HPV infection because 98.5% of the participants were married and had a single sexual partner. However, the Hani women and the women who had a rural background and multiple children and a history of sexually transmitted infections (STIs) had a significantly higher risk of being infected with HPV (Table
Detection of cervical human papillomavirus (HPV) DNA according to potential risk factors in the Hani and Han women.
Variables | Han ( |
Hani ( |
| |||||
---|---|---|---|---|---|---|---|---|
Total | Positive | OR |
|
Total | Positive | OR |
||
Work | 0.95 | 0.27 | ||||||
Yes | 102 | 13 | 1 | 50 | 6 | 1 | ||
No | 57 | 7 | 0.96 (0.23–4.23) | 187 | 44 | 2.13 (0.55–8.27) | ||
Age (years) | 0.06 |
|
||||||
<35 | 9 | 3 | 1 | 65 | 15 | 1 | ||
36–45 | 120 | 15 | 0.17 (0.03–1.07) | 111 | 19 | 0.41 (0.16–1.08) | ||
>46 | 30 | 2 | 0.06 (0.005–0.64) | 61 | 16 | 1.09 (0.38–3.17) | ||
Area | 0.91 |
|
||||||
Rural | 36 | 4 | 1 | 168 | 40 | 1 | ||
Urban | 123 | 16 | 1.13 (0.14–9.02) | 69 | 10 | 0.15 (0.05–0.41) | ||
Education | 0.86 |
|
||||||
Graduate | 61 | 7 | 1 | 23 | 3 | 1 | ||
High | 25 | 4 | 1.43 (0.3–6.77) | 21 | 5 | 2.21 (0.33–14.68) | ||
Middle | 37 | 4 | 0.86 (0.16–4.49) | 56 | 7 | 0.4 (0.06–2.66) | ||
Primary | 30 | 5 | 2.16 (0.3–15.46) | 92 | 24 | 1.28 (0.19–8.76) | ||
Illiterate | 6 | 0 | — | — | 45 | 11 | 2.63 (0.36–19.2) | |
Married status | 0.25 | — | ||||||
Yes | 155 | 19 | 1 | 235 | 50 | — | ||
No | 4 | 1 | 4.37 (0.36–53.39) | 2 | — | — | ||
Sexual partner | 0.76 | — | ||||||
Single | 137 | 16 | 1 | 234 | 50 | — | ||
Multiple | 24 | 4 | 1.25 (0.3–5.17) | 3 | — | — | ||
Babies | 0.8 |
|
||||||
No | 23 | 2 | 1 | 12 | 2 | 1 | ||
Single | 87 | 13 | 1.98 (0.18–21.97) | 73 | 7 | 0.93 (0.14–6.09) | ||
Multiple | 49 | 7 | 2.55 (0.16–39.41) | 152 | 39 | 5.35 (0.94–30.47) | ||
Illness history | 0.47 |
|
||||||
Yes | 17 | 2 | 1 | 27 | 10 | 1 | ||
No | 142 | 18 | 2.04 (0.3–13.92) | 210 | 40 | 3.15 (1.12–8.88) |
Cervical malignancy is the 8th most common cancer among Chinese females [
In this study, the overall HPV infection rate of 17.6% was higher than the documented rates in neighbouring countries (6.2% in Southeast Asia, 6.6% in south central Asia, and 8.0% in other Asian countries) [
HR-HPV prevalence has been examined in previous investigations due to its vital role in the development of cervical cancer [
An understanding of HPV genotype distributions in different areas or populations is crucial for HPV prevention and vaccine development. In this study, HPV-16 (3.5%) was detected as the most frequent genotype among the women in both ethnic groups, but it was more common among the Hani women (3.8%) than the Han women (3.1%). However, coinfection with HPV-18, which is considered a highly carcinogenic genotype, and HPV-16 was not frequently detected in this study [
Age is another important factor affecting HPV prevalence due to the various physiological developmental stages. A cross-sectional study of women from Hong Kong has shown that an initial infection peak occurs at young ages, with a second peak occurring in women over 60 years of age, while a single peak in HPV prevalence has been detected in 20- to 29-year-old Guangzhou women. Thereafter, the prevalence has been shown to decrease with increase in age [
Age-specific prevalence of human papillomavirus DNA and corresponding 95% confidence interval (Han, Yunnan, China, 2015).
Women residing in a rural area were found to be at high risk of HPV infection. Most of the Hani women were from rural areas, where they lived in concentrated villages. The sanitary conditions in their houses were found to be the worst. Further, medical hospitals in these areas are lacking, and if inhabitants become sick, they prefer to be treated at home with their traditional medicine. A possible interpretation of these findings is that women living in villages without health care facilities may be at high risk of HPV infection and the development of cervical cancer. It is therefore crucial to identify these populations and to stress the importance of cervical screening. Various reproductive characteristics are linked to the acquisition of HPV infection. In this study, Hani women with a past history of sexually transmitted diseases and those with multiple children were at significantly higher risk of HPV infection. This finding suggests that sexually transmitted diseases may also be a risk factor for HPV infection in other populations [
We have identified different HPV prevalence rates and genotype distributions among the Hani and Han women and have described the roles of different potential risk factors in the acquisition of HPV infection. Further, we have determined the age-specific HPV infection rates among these two groups; however, there are still some limitations to this study. For example, the number of participants is low, particularly the Han women (<35 years, >46 years). Thus, the results generated from the two groups are unreliable, which limits the generalizability of the findings. In view of the findings of previous studies indicating that the older age group is at high risk of acquiring HPV infection due to their compromised immune systems, it is crucial to perform further investigations to clarify our results.
To our knowledge, this is the first Hani ethnic population-based study conducted in Yunnan, China. Significantly higher prevalence rates of both general HPV and single HPV genotype infection were discovered among the Hani women compared with the Han women. A young age was found to be a risk factor for acquiring HPV infection. In addition, residing in a rural area, a past history of STIs, and a history of multiple pregnancies were found to be associated with acquisition of HPV infection. These findings contribute to the understanding of the epidemiological characteristics of HPV among women in different ethnic groups and will facilitate the design of effective strategies for the prevention and control of HPV.
Sexually transmitted infection
Human papillomavirus
High-risk human papillomavirus
Odds ratio
Confidence interval.
The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the paper.
All authors declare that they have no actual or potential competing interests.
Professor Xueshan Xia, Xiaomei Wu, and Zulqarnain Baloch designed the study and wrote the paper. Zulqarnain Baloch and Lei Yue performed genotyping and data analysis. Xiao Li and Yanqing Liu performed the sample collection. Li Liu and A-mei Zhang contributed to collecting information from the participants. All of the authors read and approved the final version of the paper. Zulqarnain Baloch and Lei Yue contributed equally to this work.
The authors sincerely thank all of the participants who took part in this study. This study was supported by research grants from the Natural Science Foundation of China (81260248, 81360247) and the Key and New Product Development Project of Yunnan Province (2013BC009). The authors sincerely thank Dr. Quaid Zaman (late) and Saqlain Abbas for their assistance with paper revision.