title: Decreasing age at first anal intercourse among men who have sex with men in China: a multicentre cross-sectional survey.
abstract: Literature on the age at first anal intercourse (AFAI) among men who have sex with men (MSM) is limited. We aimed to elucidate the evolution of AFAI and the factors associated with early AFAI, based on a large sample of MSM in China.
  
  
  
  We collected information on the demographics and sexual behaviours of MSM from seven large cities in China from 2012 to 2013. Blood samples were collected for HIV serology. AFAI was calculated for MSM born in different time periods. Linear regression models were used to explore factors associated with younger AFAI.
  
  
  
  A total of 4491 MSM (median age: 27 years, median AFAI: 21 years) were recruited. Median AFAI decreased steadily from 33 years of age among MSM born from 1940 to 1959 to 18 years of age among MSM born from 1990 to 1996. Factors significantly associated with younger AFAI included more recent birth cohort, being unmarried or living with a male partner, being a student or industry worker, the gender of the first partner being male, and using Rush or Ecstasy in the past six months (p for all <0.05).
  
  
  
  AFAI among MSM in China has considerably decreased over the past few decades. The decreasing AFAI and factors associated with younger AFAI point to the necessity of early sex education and control of recreational drug use among MSM in China.
authors: Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Yuexiu District, Guangzhou, P.R. China.|Guangdong Center for Skin Disease & STI Control, Guangzhou, Guangdong, China.|Kirby Institute, University of New South Wales, Sydney, Australia.
authors: Huachun
authors: H
authors: Zou
authors: Key Laboratory of AIDS Immunology of National Health and Family Planning Commission, Department of Laboratory Medicine, The First Affiliated Hospital, China Medical University, Shenyang, China.|Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors: Junjie
authors: J
authors: Xu
authors: Key Laboratory of AIDS Immunology of National Health and Family Planning Commission, Department of Laboratory Medicine, The First Affiliated Hospital, China Medical University, Shenyang, China.|Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors: Qinghai
authors: Q
authors: Hu
authors: Key Laboratory of AIDS Immunology of National Health and Family Planning Commission, Department of Laboratory Medicine, The First Affiliated Hospital, China Medical University, Shenyang, China.|Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors: Yanqiu
authors: Y
authors: Yu
authors: Jiangsu Provincial Centers for Disease Control and Prevention, Nanjing, China.
authors: Gengfeng
authors: G
authors: Fu
authors: He'nan Provincial Centers for Disease Control and Prevention, Zhengzhou, Zhengdong, China.
authors: Zhe
authors: Z
authors: Wang
authors: Yunnan Provincial Centers for Disease Control and Prevention, Kunming, China.
authors: Lin
authors: L
authors: Lu
authors: Shanghai Municipal Centers for Disease Control and Prevention, Shanghai, China.
authors: Minghua
authors: M
authors: Zhuang
authors: Hu'nan Provincial Centers for Disease Control and Prevention, Changsha, China.
authors: Xi
authors: X
authors: Chen
authors: Shandong Provincial Centers for Disease Control and Prevention, Jinan, China.
authors: Jihua
authors: J
authors: Fu
authors: National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Changping District, Beijing, China.
authors: Zhenhai
authors: Z
authors: Zhou
authors: Key Laboratory of AIDS Immunology of National Health and Family Planning Commission, Department of Laboratory Medicine, The First Affiliated Hospital, China Medical University, Shenyang, China.|Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors: Wenqing
authors: W
authors: Geng
authors: Key Laboratory of AIDS Immunology of National Health and Family Planning Commission, Department of Laboratory Medicine, The First Affiliated Hospital, China Medical University, Shenyang, China.|Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors: Yongjun
authors: Y
authors: Jiang
authors: Key Laboratory of AIDS Immunology of National Health and Family Planning Commission, Department of Laboratory Medicine, The First Affiliated Hospital, China Medical University, Shenyang, China.|Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China; hongshang100@hotmail.com.
authors: Hong
authors: H
authors: Shang
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001003:Anal Canal; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D015658:HIV Infections / Q000453:epidemiology; D018451:Homosexuality, Male / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012725:Sexual Behavior / Q000706:statistics & numerical data; D012747:Sexual Partners; D019966:Substance-Related Disorders; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: AFAI; China; HIV; MSM; birth cohort; recreational drug