title: Low-grade systemic inflammation and suboptimal bone mineral density throughout adolescence: a prospective study in girls.
abstract: OBJECTIVE
  We aimed at quantifying the associations between high-sensitivity C-reactive protein (hs-CRP) and forearm bone mineral density (BMD) throughout adolescence in overweight and normal-weight girls.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  346 girls born in 1990 and attending schools in Porto, Portugal.
  
  
  METHODS
  Adolescents were evaluated at 13 and 17 years of age using a standard protocol. Forearm BMD was measured by dual-energy X-ray absorptiometry. Anthropometric assessment included weight, height, body fat percentage and waist circumference. Girls were categorized according to age- and sex-specific body mass index (BMI) percentiles as normal weight in both evaluations or overweight in at least one assessment. Pubertal development was estimated using menarche age. Serum hs-CRP was determined using particle-enhanced immunonephelometry. Hs-CRP was log-transformed, and associations were quantified using linear regression coefficients and 95% confidence intervals (95%CI).
  
  
  RESULTS
  An inverse association between hs-CRP and BMD was observed from 13 years of age in overweight girls [-11·26 mg/cm(2) (-21·99, -0·52)]. Among normal-weight adolescents, 13-year-old hs-CRP was negatively associated with prospective BMD variation between 13 and 17 years of age [-1·90 mg/cm(2) year (-3·35, -0·45)]. Overweight girls who maintained higher levels of hs-CRP throughout adolescence had lower 17-year-old BMD (adjusted mean 0·441 vs 0·483 g/cm(2) in those who remained with lower levels of hs-CRP). At 17 years of age, significant inverse associations were found between hs-CRP and BMD among normal-weight and overweight girls.
  
  
  CONCLUSIONS
  Obesity-related early systemic inflammation might be involved in suboptimal bone accrual, particularly in overweight girls.
authors.affiliation: Department of Hygiene and Epidemiology, University of Porto Medical School, Porto, Portugal. rlucas@med.up.pt
authors.forename: Raquel
authors.initials: R
authors.lastname: Lucas
authors.forename: Elisabete
authors.initials: E
authors.lastname: Ramos
authors.forename: Andreia
authors.initials: A
authors.lastname: Oliveira
authors.forename: Teresa
authors.initials: T
authors.lastname: Monjardino
authors.forename: Henrique
authors.initials: H
authors.lastname: Barros
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D001823:Body Composition / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D002097:C-Reactive Protein / Q000378:metabolism; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000276:immunology* / Q000378:metabolism*; D050177:Overweight / Q000276:immunology / Q000378:metabolism; D011446:Prospective Studies; D055105:Waist Circumference / Q000502:physiology
chemical_list: D002097:C-Reactive Protein