OBJECTIVEThe aim of the study was to investigate the positivity of human papillomavirus (HPV) and the possible related risk factors for HPV infection in certain district government in Daqing city, Heilongjiang province.

METHODSA total of 2015 female staffs who participated cervical cancer screening were selected as subjects, in certain district government in Daqing city, Heilongjiang province, from June to October, 2010. First of all, a standardized questionnaire was used for collection of subject's demographic information and possible risk factors. Afterwards, cervical cytological and HPV DNA testing were applied to all participants. Subjects with suspected cervical intraepithelial neoplasia (CIN) or cervical cancer were recalled for taking biopsy under colposcopy for further histopathological diagnosis. Standardized HPV positivity by Segi's world population and compared the difference of HPV positivity of different types. The positivity of HPV between women with and without cervical abnormalities were compared by unconditional logistic regression. And the possible risk factors for HPV infection were also investigated.

RESULTSA total of 1759 out of 2015 subjects had gynecological examination, among which 152 subjects were HPV positive. The positivity of HPV was 8.64% (95%CI: 7.37% - 10.05%), and it was 8.47% (95%CI: 7.93% - 9.03%) after age standardization. Finally, 57 (3.24%) and 1702 (96.76%) subjects had abnormal (≥ CIN1 or low-grade squamous intraepithelial lesion (LSIL)) and normal cervix, respectively. The HPV positivity between women with and without cervical abnormalities were 73.68% (42/57) and 6.46% (110/1702), respectively. There was a significant difference (χ(2) = 307.23, P < 0.05) in HPV positivity between women with and without cervical abnormalities. The risk of cervical abnormalities for women with HPV positivity was 40.52 times (95%CI: 21.79 - 75.36) higher than that for women with HPV negativity. Among women with cervical abnormalities, the most three common HPV types, in descending order, were HPV16 (28.07% (16/57)), HPV52 (14.04% (8/57)) and HPV58 (12.28% (7/57)). While among women with normal cervix, the most three common HPV types were HPV52 (1.23% (21/1702)), HPV16 (1.00% (17/1702)) and HPV58 (0.71% (12/1702)). The positivity of HPV clade A9 among women with and without cervical abnormalities were 59.65% (34/57) and 3.23% (55/1702), which were higher than that of other clades. Analysis for risk factors of HPV infection showed that smoking (OR = 2.71, 95%CI: 1.00 - 7.33), late age (≥ 15 years old) of menarche (OR = 1.44, 95%CI: 1.00 - 2.05), early age (≤ 20 years old) of marriage (OR = 3.09, 95%CI: 1.30 - 7.35), multiple (≥ 2) sexual partners (OR = 2.69, 95%CI: 1.46 - 4.95), husband's extramarital sexual behaviors (OR = 2.77, 95%CI: 1.25 - 6.12) and multiple (≥ 2 times) parity (OR = 1.77, 95%CI: 1.03 - 3.03) would increase the risk of HPV positivity.

CONCLUSIONHPV positivity among women with cervical abnormalities was significantly higher than that among women with normal cervix. HPV16, 52, 58 were the major genotypes among the study population. Smoking, late age of menarche, early age of marriage, multiple sexual partners, husband extramarital sexual behaviors and multiple parity increase the risk of HPV infection.