Min Dai

Smoking and human papillomavirus infection: pooled analysis of the International Agency for Research on Cancer HPV Prevalence Surveys

BACKGROUND Smoking increases the risk of squamous-cell carcinoma of the cervix, but it is not clear whether smoking increases the risk of acquisition or persistence of human papillomavirus (HPV) infection. METHODS Information on smoking was collected from 10 areas in four continents among population-based, age-stratified random samples of women aged 15 years or older. HPV testing was performed using PCR-based enzyme immunoassay. Unconditional logistic regression was used to estimate odds ratios (OR) and corresponding 95% confidence intervals (CI) of being HPV-positive by smoking habits, adjusted for age and lifetime number of sexual partners. RESULTS Ten thousand five hundred and seventy-seven women (mean age 41.4 years) were included. Among current smokers, the risk of being HPV-positive increased with smoking intensity, after allowing for lifetime number of sexual partners: ORs for <5, 5-14 and >/=15 cigarettes per day were 1.21 (95% CI 0.95-1.54), 1.39 (95% CI 1.04-1.87) and 2.01 (95% CI 1.32-3.08), respectively, as compared with never-smokers. The risk among former smokers (OR = 0.95, 95% CI 0.73-1.23) was similar to that among never-smokers. Analyses stratified by lifetime number of sexual partners showed a significant trend in risk only for women with one lifetime sexual partner. CONCLUSIONS Our study suggests that current, though not former, smoking is associated with an increased prevalence of HPV, after allowance for sexual covariates. Among current smokers, HPV prevalence increased with smoking intensity, but a clear dose-response relationship was exclusively seen among women who declared one lifetime sexual partner.

Human papillomavirus infection in Shanxi Province, People's Republic of China: a population-based study

To investigate the prevalence of, and risk factors for, cervical infection with human papillomavirus (HPV) in the rural province of Shanxi, Peoples Republic of China, which has relatively high cervical cancer mortality rates, we interviewed and obtained cervical cell samples from 662 women aged 15–59 years. A total of 24 different HPV types were identified using a GP5+/6+-based PCR assay able to detect 44 different HPV types. Human papillomavirus prevalence was 14.8% overall and 9.6% among women without cervical abnormalities (14.2 and 8.9%, respectively, age standardised to the world standard population). Multiple-type infections accounted for 30.6% of all infections. By far the most commonly found type was HPV16 (5.7% of all women and 38.8% of HPV-positive women), followed by HPV 58, 52, 33 and 18. Unlike most previous studies published, HPV prevalence was lower among women younger than 35 years (8.7%) than those older than 35 years (17.8%). High-risk HPV types predominated in all age groups. Although low-risk HPV types were rare in young women, they became more common with increasing age. 92.3% of women with cervical intraepithelial neoplasia grade 3 were infected with high-risk HPV types, but none with low-risk types only. No significant difference in HPV positivity was observed by educational level, sexual habits, reproductive history or use of contraceptive methods in this rural low-income Chinese population.

Reproductive Factors, Oral Contraceptive Use, and Human Papillomavirus Infection: Pooled Analysis of the IARC HPV Prevalence Surveys

High parity, early age at first full-term pregnancy (FTP), and long-term oral contraceptive (OC) use increase cervical cancer risk, but it is unclear whether these variables are also associated with increased risk of acquisition and persistence of human papillomavirus (HPV) infection, the main cause of cervical cancer. Information on reproductive and menstrual characteristics and OC use were collected from 14 areas worldwide, among population-based, age-stratified random samples of women aged 15 years or older. HPV testing was done using PCR-based enzyme immunoassay. Unconditional logistic regression was used to estimate the odds ratios (OR) of being HPV-positive according to reproductive and menstrual factors and corresponding 95% confidence intervals (CI). When more than two groups were compared, floating CIs (FCI) were estimated. A total of 15,145 women (mean age, 40.9 years) were analyzed. Women with ≥5 FTPs (OR, 0.90; 95% FCI, 0.76-1.06) showed a similar risk of being HPV-positive compared with women with only one FTP (OR, 1.00; 95% FCI, 0.86-1.16). However, nulliparous women showed an OR of 1.40 (95% CI, 1.16-1.69) compared with parous women. Early age at first FTP was not significantly related to HPV positivity. HPV positivity was similar for women who reported ≥10 years of use of OCs (OR, 1.16; 95% FCI, 0.85-1.58) and never users of OCs (OR, 1.00; 95% FCI, 0.90-1.12). Our study suggests, therefore, that high parity, early age at first FTP, and long-term OC use are not associated with HPV prevalence, but rather these factors might be involved in the transition from HPV infection to neoplastic cervical lesions. (Cancer Epidemiol Biomarkers Prev 2006;15(11):2148–53)

Human Papillomavirus Type 16 and TP53 Mutation in Oral Cancer Matched Analysis of the IARC Multicenter Study

TP53 mutations were analyzed in 35 human papillomavirus (HPV) type 16 DNA-positive cancers of the oral cavity and oropharynx and in 35 HPV DNA-negative cancers matched by subsite, country, sex, age, and tobacco and alcohol consumption. Wild-type TP53 was found more frequently in cancer specimens that contained HPV16 DNA than in those that did not. All 14 HPV16 DNA-positive cancers in HPV16 E6 antibody-positive patients contained wild-type TP53, compared with 50% of corresponding HPV DNA-negative cancers (matched odds ratio, ∞; 95% confidence interval, 1.4–∞). In contrast, for HPV16 DNA-positive cancers in E6-negative patients, wild-type TP53 frequency was similar to that in corresponding HPV DNA-negative cancers (matched odds ratio, 1.0; 95% confidence interval, 0.2–5.4). TP53 inactivation is a major mechanism of HPV-related carcinogenesis in the oral cavity and oropharynx. The role of HPV in cancers also containing TP53 mutations remains to be clarified.

Human papillomavirus infection in Shenyang City, People's Republic of China: a population-based study

To investigate the prevalence of, and risk factors for, cervical infection with human papillomavirus (HPV) in Shenyang City, Peoples Republic of China, we interviewed and obtained cervical cell samples from 685 women aged 15–59 years enumerated from local population lists. Human papillomavirus DNA was detected in cervical cell samples using a GP5+/6+-based PCR assay for 44 HPV types. Human papillomavirus prevalence was 16.8% overall and 13.6% among women without cervical abnormalities (16.6% and 12.4%, respectively, age-standardised to the world standard population), with no significant trends in HPV prevalence by age group. Of the 32 types identified, high-risk HPV types predominated in all age groups, HPV16 being the most common (3.4% of all women), followed by HPV52 (2.5%) and 58 (1.9%). Multiple-type infections accounted for 31.3% of all infected women. Not being married, reporting multiple sexual partners and husbands extramarital sexual relationships were all significantly associated with being HPV-positive. The disclosure of a relatively high HPV prevalence in Shenyang, in comparison with other worldwide populations, raises important questions concerning the prevention of cervical cancer in China, especially given the promising efficacy of prophylactic HPV vaccines.

Human papillomavirus infection in women in Shenzhen City, People's Republic of China, a population typical of recent Chinese urbanisation.

Select cancer registries report that cervical cancer is relatively rare in the Peoples Republic of China, but may not be representative of the entire country. We carried out a survey of human papillomavirus (HPV) prevalence in 3 samples of women, i.e., general population, factory workers, and tertiary sector workers, in Shenzhen City in 2004. All participants were interviewed and offered gynaecological examination. HPV detection in exfoliated cervical cells was performed using a GP5+/6+ PCR‐based assay. Overall HPV prevalence was 18.4% among the general population (n = 534), 11.2% among factory workers (n = 269) and 18.8% among tertiary sector workers (n = 224). Corresponding prevalence for high‐risk HPV types was 13.5%, 8.2% and 13.8%, respectively. The most commonly found HPV types were HPV16, 52, 58, 31 and 39. HPV prevalence significantly increased with age in the general population, whereas it was highest below age 25 years in tertiary sector workers. Associations of HPV prevalence with indicators of sexual behaviour were stronger among tertiary sector workers than in the other samples of women. High HPV prevalence in all age groups and the appearance of a ‘western‐type’ peak in HPV prevalence among young women employed in the tertiary sector raise important questions concerning the real cervical cancer burden, and its control, in urban China.

Epidemiology and Prevention of Human Papillomavirus and Cervical Cancer in China and Mongolia

To develop a comprehensive intervention policy for future management of cervical cancer in China and Mongolia, it is essential to review the prevalence of human papillomavirus (HPV) infection, cervical cancer incidence and mortality, status of cervical screening and issues related to prophylactic HPV vaccines. Invasive cervical cancer (ICC) remains an important health problem among women in both China and Mongolia. However, a significant proportion of the burden is observed in rural settings. In areas of China and Mongolia where data are available, HPV prevalence is relatively high, with sexual activity being the most important risk factor. Nationwide programs for cervical cancer screening do not exist, and the majority of women have never been screened. However, government and non-governmental organizations have been collaborating to establish demonstration centers in both high- and low-resource settings to provide screening and obtain geographic specific data. To date, the prophylactic HPV vaccines are not licensed in China or Mongolia, although with wide coverage, the HPV vaccine could potentially prevent as much as three quarters of ICC cases among Chinese and Mongolian women. Ultimately, the introduction of HPV vaccination will present specific challenges, as well as opportunities, for developing advocacy, information and communication strategies that will involve policymakers and the general public.

Epidermodysplasia verruciformis human papillomavirus types and carcinoma of the conjunctiva: a pilot study

A total of 21 squamous-cell carcinoma of the conjunctiva (SCC) and 22 control subjects had conjunctival samples tested for human papillomavirus (HPV) types using PCR-based assays. Epidermodysplasia verruciformis HPV types were found in 86% of SCC cases and 36% of control subjects (Odds ratio=12.0), suggesting a role of HPVs in the aetiology of SCC.

Human papillomavirus infection among 100 oesophageal cancer cases in the People's Republic of China

Human papillomavirus infection among 100 oesophageal cancer cases in the People’s Republic of China Min Dai, Wei-dong Zhang, Gary M. Clifford, Tarik Gheit, Bao-chang He, Kristina M. Michael, Tim Waterboer, Pierre Hainaut, Massimo Tommasino and Silvia Franceschi* International Agency for Research on Cancer, Lyon, France Department of Epidemiology, Zhengzhou University, Zhengzhou, China Department of Epidemiology, Fujian Medical University, Fuzhou, China Infection and Cancer Program, German Cancer Research Center (DKFZ), Heidelberg, Germany