title: Physical activity in relation to serum sclerostin, insulin-like growth factor-1, and bone turnover markers in healthy premenopausal women: a cross-sectional and a longitudinal study.
abstract: BACKGROUND
  There is limited information on the effects of mechanical loading caused by physical activity (PA) on sclerostin, IGF-I, and bone turnover markers (BTM).
  
  
  OBJECTIVE
  The objective of the investigation was to study the relationships between serum sclerostin, serum-IGF-I (s-IGF-I), BTM, and the PA level in premenopausal women and to discern how 8 wk of PA training (PAT) affects the serum levels of sclerostin, IGF-I, and BTM.
  
  
  METHODS
  This was a cross-sectional study with a subgroup followed up longitudinally.
  
  
  METHODS
  A total of 1235 randomly selected premenopausal women were cross-sectionally studied. We also followed up 58 of these women longitudinally during an 8-wk course of PAT (4 d/wk) and compared them with 62 controls. All women were medically examined, and bone mineral density (BMD) and serum levels of sclerostin, s-IGF-I, and BTM were determined.
  
  
  RESULTS
  Women with PA of greater than 120 min/wk showed significantly lower serum sclerostin (by 36.8%) but higher s-IGF-I (by 107%) levels than sedentary controls. Bone formation markers were also higher in the PA greater than 120 min/wk group compared with the sedentary controls. In the longitudinal study, the 8-wk PAT program led to a decrease in serum sclerostin (by 33.9%, P<0.0001) but increases in the serum levels of the bone-formation markers and IGF-I (s-IGF-I by 74.2%, P<0.0001).
  
  
  CONCLUSIONS
  This study demonstrates that even minor changes in PA are associated with effects on serum levels of sclerostin, IGF-I, and BTM and suggests that sclerostin could be a link between mechanical loading and disuse osteoporosis in humans.
authors.affiliation: Center of EXcellence for Osteoporosis Research, Department of Clinical Biochemistry, Faculty of Medicine and King Abdulaziz University Hospital, King Abdulaziz University, P.O. Box 20724, Jeddah 21465, Saudi Arabia. msmardawi@yahoo.com
authors.forename: Mohammed-Salleh M
authors.initials: MS
authors.lastname: Ardawi
authors.forename: Abdulrahim A
authors.initials: AA
authors.lastname: Rouzi
authors.forename: Mohammed H
authors.initials: MH
authors.lastname: Qari
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D015415:Biomarkers / Q000097:blood; D019485:Bone Morphogenetic Proteins / Q000097:blood*; D016723:Bone Remodeling / Q000502:physiology; D001842:Bone and Bones / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005819:Genetic Markers; D006306:Health Surveys / Q000706:statistics & numerical data; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008137:Longitudinal Studies; D009043:Motor Activity / Q000502:physiology*; D010024:Osteoporosis / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D017697:Premenopause / Q000097:blood*; D012307:Risk Factors; D012529:Saudi Arabia / Q000453:epidemiology; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015415:Biomarkers; D019485:Bone Morphogenetic Proteins; D005819:Genetic Markers; C422903:SOST protein, human; D007334:Insulin-Like Growth Factor I