title: Exercise protects against glucose intolerance in individuals with a small body size at birth.
abstract: BACKGROUND
  Small body size at birth is a risk factor for Type 2 diabetes. We investigated whether regular exercise is related to lower rates of glucose intolerance in individuals with a small body size at birth and whether birth size affects exercise habits in adulthood.
  
  
  METHODS
  Five hundred subjects aged 65-75 years with data on birth measurements underwent an oral glucose tolerance test. They reported their weekly exercise frequency and intensity and yearly physical leisure time activity.
  
  
  RESULTS
  Frequent (> or = 3/week) or moderate weekly exercise and yearly physical activity were all related to lower rates of glucose intolerance. This effect was, however, dependent on birth size, being strongest among subjects with a small body size at birth (birth weight < or = 3000 g and/or ponderal index < or = 26 kg/m3). Among men, frequency (P = 0.033) and intensity (P = 0.030) of exercise as well as yearly physical activity (P = 0.005) correlated inversely with birth size.
  
  
  CONCLUSIONS
  Subjects predisposed to Type 2 diabetes due to a small birth size are strongly protected from glucose intolerance by regular exercise. Although a small body size at birth is related to a smaller muscle mass in adulthood, men born thin exercised more in adulthood than those not born thin. In these elderly subjects this might indicate the survival of the fittest.
authors.affiliation: Department of Epidemiology and Health Promotion, National Public Health Institute, FIN-00300 Helsinki, Finland. johan.eriksson@ktl.fi
authors.forename: Johan G
authors.initials: JG
authors.lastname: Eriksson
authors.forename: Hilkka
authors.initials: H
authors.lastname: Ylihärsilä
authors.forename: Tom
authors.initials: T
authors.lastname: Forsén
authors.forename: Clive
authors.initials: C
authors.lastname: Osmond
authors.forename: David J P
authors.initials: DJ
authors.lastname: Barker
mesh_terms: D000368:Aged; D003922:Diabetes Mellitus, Type 1 / Q000209:etiology* / Q000517:prevention & control; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D005387:Finland / Q000453:epidemiology; D018149:Glucose Intolerance / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D005951:Glucose Tolerance Test; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D015995:Prevalence