title: Temporal relationship between insulin sensitivity and the pubertal decline in physical activity in peripubertal Hispanic and African American females.
abstract: OBJECTIVE
  Little attention has been paid to possible intrinsic biological mechanisms for the decline in physical activity that occurs during puberty. This longitudinal observational study examined the association between baseline insulin sensitivity (SI) and declines in physical activity and increases in sedentary behavior in peripubertal minority females over a year.
  
  
  METHODS
  Participants were Hispanic and African American girls (n = 55; 76% Hispanic; mean age 9.4 years; 36% obese). SI and other insulin indices were measured at baseline using the frequently sampled intravenous glucose tolerance test. Physical activity was measured on a quarterly basis by accelerometry and self-report.
  
  
  RESULTS
  Physical activity declined by 25% and time spent in sedentary behaviors increased by ∼13% over 1 year. Lower baseline SI predicted the decline in physical activity measured by accelerometry, whereas higher baseline acute insulin response to glucose predicted the decline in physical activity measured by self-report. Time spent in sedentary behavior increased by ~13% over 1 year, and this was predicted by lower baseline SI. All models controlled for adiposity, age, pubertal stage, and ethnicity.
  
  
  CONCLUSIONS
  When evaluated using a longitudinal design with strong outcome measures, this study suggests that lower baseline SI predicts a greater decline in physical activity in peripubertal minority females.
authors.affiliation: Corresponding author: Donna Spruijt-Metz, dmetz@usc.edu.
authors.forename: Donna
authors.initials: D
authors.lastname: Spruijt-Metz
authors.forename: Britni R
authors.initials: BR
authors.lastname: Belcher
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Hsu
authors.forename: Arianna D
authors.initials: AD
authors.lastname: McClain
authors.forename: Chih-Ping
authors.initials: CP
authors.lastname: Chou
authors.forename: Selena
authors.initials: S
authors.lastname: Nguyen-Rodriguez
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Weigensberg
authors.forename: Michael I
authors.initials: MI
authors.lastname: Goran
mesh_terms: D050154:Adiposity / Q000502:physiology; D001741:Black or African American; D002648:Child; D005260:Female; D005951:Glucose Tolerance Test; D006630:Hispanic or Latino; D006801:Humans; D007333:Insulin Resistance / Q000208:ethnology* / Q000502:physiology; D008137:Longitudinal Studies; D009043:Motor Activity; D009765:Obesity / Q000208:ethnology / Q000503:physiopathology; D011627:Puberty / Q000208:ethnology* / Q000502:physiology; D013997:Time Factors; D044465:White People