title: Association between physical activity and urinary estrogens and estrogen metabolites in premenopausal women.
abstract: OBJECTIVE
  The objective of the study was to evaluate in premenopausal women the relationships of physically active and sedentary behaviors reported for adulthood and adolescence with a comprehensive profile of estrogen metabolism.
  
  
  METHODS
  Fifteen estrogens and estrogen metabolites (jointly termed EM) were measured using liquid chromatography-tandem mass spectrometry in luteal phase urines from 603 premenopausal women in the Nurses' Health Study II. Geometric means of individual EM, metabolic pathway groups, and pathway ratios were examined by level of exposure after adjustment for age, body mass index, alcohol intake, menstrual cycle length, and sample collection timing.
  
  
  RESULTS
  High overall physical activity in adulthood (42+ metabolic equivalent h/wk vs. <3 metabolic equivalent h/wk) was associated with a 15% lower level of urinary estradiol (Ptrend=0.03) and 15% lower level of 16-hydroxylation pathway EM (Ptrend=0.03). Levels of 2- and 4-hydroxylation pathway EM did not differ significantly by physical activity. High overall activity was also positively associated with four ratios: 2-pathway EM to parent estrogens (Ptrend=0.05), 2-pathway catechols to parent estrogens (Ptrend=0.03), 2-pathway catechols to methylated 2-pathway catechols (Ptrend<0.01), and 2-hydroxyestrone to 16α-hydroxyestrone (Ptrend=0.01). Similar patterns of association were noted for walking and vigorous physical activity, but there was little evidence of associations with sedentary behaviors or activity during adolescence.
  
  
  CONCLUSIONS
  High levels of physical activity were associated with lower levels of parent estrogens and 16-hydroxylation pathway EM and preferential metabolism to 2-pathway catechols. The results of our analysis, the largest, most comprehensive examination of physical activity and estrogen metabolism to date, may be useful in future studies investigating the etiology of diseases linked to both physical activity and endogenous estrogen.
authors.affiliation: Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 6120 Executive Boulevard, Room 3028, Bethesda, Maryland 20892-7246, USA. charles.matthews2@nih.gov
authors.forename: Charles E
authors.initials: CE
authors.lastname: Matthews
authors.forename: Renee T
authors.initials: RT
authors.lastname: Fortner
authors.forename: Xia
authors.initials: X
authors.lastname: Xu
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hankinson
authors.forename: A Heather
authors.initials: AH
authors.lastname: Eliassen
authors.forename: Regina G
authors.initials: RG
authors.lastname: Ziegler
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine; D002853:Chromatography, Liquid; D003430:Cross-Sectional Studies; D004967:Estrogens / Q000378:metabolism* / Q000652:urine*; D005260:Female; D006801:Humans; D006894:Hydroxyestrones / Q000378:metabolism / Q000652:urine; D008183:Luteal Phase / Q000652:urine*; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D017697:Premenopause / Q000652:urine*; D053719:Tandem Mass Spectrometry
chemical_list: D015415:Biomarkers; D004967:Estrogens; D006894:Hydroxyestrones