title: Sexual Behavior and Contraceptive Use among 18- to 19-Year-Old Adolescent Women by Weight Status: A Longitudinal Analysis.
abstract: OBJECTIVE
  To describe the association between weight status and sexual practices among 18- to 19-year-old women.
  
  
  METHODS
  We analyzed a population-based longitudinal study of 18- to 19-year-old women residing in a Michigan county at cohort inception. Weekly journal surveys measured sexual practices, including contraceptive behaviors. Outcomes included proportion of weeks with a partner, proportion of weeks with sexual intercourse, number of partners, average length of relationships, proportion of weeks with contraception use, and proportion of weeks where contraception was used consistently. We examined 26,545 journal surveys from 900 women over the first study year. Ordinary least squares regression models for each outcome examined differences by weight status, controlling for sociodemographic characteristics.
  
  
  RESULTS
  The mean proportion of weeks in which adolescents reported sexual intercourse was 52%; there was no difference by weight status. Among weeks in which adolescents reported sexual activity, obese adolescents had a lower proportion of weeks where any contraception was used compared with normal weight adolescents (84% vs 91%, P = .011). Among weeks in which adolescents reported sexual activity and contraceptive use, obese adolescents had a lower proportion of weeks with consistent contraceptive use (68% vs 78%, P = .016) and oral contraceptive pill use (27% vs 45%, P = .001) compared with normal weight adolescents. All other relationships by weight status were not statistically significant.
  
  
  CONCLUSIONS
  In this longitudinal study, obese adolescent women were less likely to use contraception, and less likely to use it consistently when compared with normal weight peers. Findings suggest obesity may be an important factor associated with adolescent women's sexual behavior.
authors.affiliation: Department of Family Medicine, University of Michigan, Ann Arbor, MI; Institute for Healthcare Policy and Innovation, University of Michigan, Ann Arbor, MI. Electronic address: tachang@med.umich.edu.
authors.forename: Tammy
authors.initials: T
authors.lastname: Chang
authors.affiliation: Institute for Healthcare Policy and Innovation, University of Michigan, Ann Arbor, MI; Department of Pediatrics and Communicable Diseases and Department of Internal Medicine, University of Michigan, Ann Arbor, MI.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Davis
authors.affiliation: Population Studies Center/Survey Research Center, Institute for Social Research, University of Michigan, Ann Arbor, MI; Department of Sociology, University of Michigan, Ann Arbor, MI.
authors.forename: Yasamin
authors.initials: Y
authors.lastname: Kusunoki
authors.affiliation: Population Studies Center/Survey Research Center, Institute for Social Research, University of Michigan, Ann Arbor, MI; Department of Sociology, University of Michigan, Ann Arbor, MI.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Ela
authors.affiliation: Population Studies Center/Survey Research Center, Institute for Social Research, University of Michigan, Ann Arbor, MI; Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI.
authors.forename: Kelli S
authors.initials: KS
authors.lastname: Hall
authors.affiliation: Population Studies Center/Survey Research Center, Institute for Social Research, University of Michigan, Ann Arbor, MI; Department of Sociology, University of Michigan, Ann Arbor, MI.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Barber
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D015992:Body Mass Index; D001835:Body Weight; D003075:Coitus; D003268:Contraception Behavior / Q000706:statistics & numerical data*; D003270:Contraceptive Agents; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008824:Michigan; D009765:Obesity / Q000150:complications*; D012307:Risk Factors; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D003270:Contraceptive Agents