title: Irregular menstruation and hyperandrogenaemia in adolescence are associated with polycystic ovary syndrome and infertility in later life: Northern Finland Birth Cohort 1986 study.
abstract: OBJECTIVE
  Do teenage girls with a history of menstrual irregularity and/or elevated androgen levels in adolescence exhibit an increased risk of polycystic ovary syndrome (PCOS) and/or infertility later on in adulthood?
  
  
  CONCLUSIONS
  Our results suggest that menstrual irregularity and/or elevated androgen levels at 16 years are still associated with symptoms of PCOS at 26 years as well as infertility problems at 26 years but not with decreased pregnancy or delivery rates at 26 years.
  
  
  BACKGROUND
  Hyperandrogenaemia is associated with menstrual irregularity, hirsutism, acne and potentially higher risk for PCOS, but there are few follow-up studies investigating whether adolescent hyperandrogenaemia and/or menstrual irregularity are an early sign of PCOS.
  
  
  METHODS
  A prospective population-based cohort study was conducted using two postal questionnaires targeting girls in the Northern Finland Birth Cohort 1986 (NFBC1986, n = 4567). The NFBC1986 comprises all expected births from the year 1986 in the two northernmost provinces of Finland. Collection of the database was performed at the age of 16 and 26. The 16-year and 26-year questionnaires included one question about the regularity and length of the menstrual cycle. The 26-year questionnaire also included questions about symptoms of PCOS, reproduction and infertility problems.
  
  
  METHODS
  The response rates for the questionnaires were 80% (n = 3669) at 16 years and 50% (n = 2270) at 26 years. At 15-16 years, of 2448 girls, 709 (29%) girls reported menstrual irregularity (symptomatic girls) and 1739 (71%) had regular periods (non-symptomatic girls). After combining data from the two questionnaires a total of 2033 girls were included in the analyses. The χ(2) and Student's t-test was used to compare reproductive outcome and prevalence of clinical hyperandrogenaemia, PCOS and infertility at 26 years between the study groups. Univariate and multivariate logistic regression models were employed to estimate the association of menstrual irregularity at 16 years with clinical hyperandrogenaemia, PCOS and infertility at 26 years.
  
  
  RESULTS
  At follow-up, the proportion of symptomatic girls who had conceived at least once (68.0 versus 67.9%) and had delivered at least one child (25.7 versus 28.1%) was similar to the non-symptomatic women and the groups had similar miscarriage rates (11.6 versus 12.1%). Logistic regression analyses indicated that menstrual irregularity at 16 years was associated with an increased risk of menstrual irregularity [adjusted odds ratio (OR) 1.37, 95% confidence interval (CI) 1.00-1.88, P = 0.050], PCOS (adjusted OR 2.91, 95% CI 1.74-4.84, P < 0.001) and infertility problems (adjusted OR 2.07, 95% CI 1.16-3.76, P = 0.013) at 26 years. At 26 years, women with PCOS (P = 0.013), hirsutism (P = 0.001) and acne (P < 0.001) exhibited significantly higher values of free androgen index (FAI) at 16 years than control women. There was a significant linear trend in the higher FAI quartiles at 16 years towards higher prevalence of PCOS (P = 0.005), hirsutism (P < 0.001) and acne (P < 0.001) at 26 years. Only 10.5% of the girls with menstrual irregularity at 16 years had PCOS at 26 years.
  
  
  CONCLUSIONS
  The diagnosis of menstrual irregularity was based on a self-reported questionnaire, thus introducing a risk of information bias in reporting the symptoms. Moreover, ovarian ultrasonography was not available to aid the diagnosis of PCOS and there was no clinical evaluation of hyperandrogenism. The relatively low rate of participation to the questionnaire at 26 years may also have biased the results.
  
  
  CONCLUSIONS
  Our findings confirm that menstrual irregularity and/or elevated androgen levels are already present in adolescence in women with PCOS and infertility in later life, which strengthens the importance of early identification of menstrual irregularity.
  
  
  BACKGROUND
  This work was supported by grants from the Finnish Medical Society Duodecim, the North Ostrobothnia Regional Fund, the Academy of Finland, the Sigrid Juselius Foundation, University Hospital Oulu and University of Oulu, the European Commission and the Medical Research Council, UK, Welcome Trust (089549/Z/09/Z). None of the authors have any conflict of interest.
authors.affiliation: Department of Obstetrics and Gynaecology, University Hospital of Oulu, University of Oulu, Oulu, Finland.
authors.forename: S
authors.initials: S
authors.lastname: West
authors.affiliation: Department of Human Metabolism, University of Sheffield, Jessop Wing, Sheffield S10 2SF, UK.
authors.forename: H
authors.initials: H
authors.lastname: Lashen
authors.affiliation: Department of Children, Young People and Families, National Institute for Health and Welfare, Oulu, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Bloigu
authors.affiliation: Institute of Reproductive and Developmental Biology, Imperial College London, London, UK.
authors.forename: S
authors.initials: S
authors.lastname: Franks
authors.affiliation: NordLab Oulu, Oulu University Hospital and Department of Clinical Chemistry, University of Oulu, Oulu, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Puukka
authors.affiliation: NordLab Oulu, Oulu University Hospital and Department of Clinical Chemistry, University of Oulu, Oulu, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Ruokonen
authors.affiliation: Department of Children, Young People and Families, National Institute for Health and Welfare, Oulu, Finland Department of Epidemiology and Biostatistics, MRC Health Protection Agency (HPA) Centre for Environment and Health, School of Public Health, Imperial College London, London, UK Institute of Health Sciences, University of Oulu, Oulu, Finland Biocenter Oulu, University of Oulu, Oulu, Finland Unit of Primary Care, University Hospital of Oulu, University of Oulu, Oulu, Finland.
authors.forename: M-R
authors.initials: MR
authors.lastname: Järvelin
authors.affiliation: Department of Obstetrics and Gynaecology, University Hospital of Oulu, University of Oulu, Oulu, Finland Department of Obstetrics and Gynaecology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: J S
authors.initials: JS
authors.lastname: Tapanainen
authors.affiliation: Department of Obstetrics and Gynaecology, University Hospital of Oulu, University of Oulu, Oulu, Finland Imp@cc.oulu.fi.
authors.forename: L
authors.initials: L
authors.lastname: Morin-Papunen
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005387:Finland; D005500:Follow-Up Studies; D006801:Humans; D017588:Hyperandrogenism / Q000150:complications* / Q000453:epidemiology; D007247:Infertility, Female / Q000150:complications*; D008599:Menstruation Disturbances / Q000150:complications*; D011085:Polycystic Ovary Syndrome / Q000150:complications* / Q000453:epidemiology; D015995:Prevalence; D013739:Testosterone / Q000097:blood
chemical_list: D013739:Testosterone
keywords: hirsutism; hyperandrogenaemia in adolescence; menstrual irregularity; oligo-amenorrhea; polycystic ovary syndrome
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