title: Adult glucose metabolism in extremely birthweight-discordant monozygotic twins.
abstract: OBJECTIVE
  Low birthweight (BW) is associated with increased risk of type 2 diabetes. We compared glucose metabolism in adult BW-discordant monozygotic (MZ) twins, thereby controlling for genetic factors and rearing environment.
  
  
  METHODS
  Among 77,885 twins in the Danish Twin Registry, 155 of the most BW-discordant MZ twin pairs (median BW difference 0.5 kg) were assessed using a 2 h oral glucose tolerance test with sampling of plasma (p-)glucose, insulin, C-peptide, glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1. HOMA for beta cell function (HOMA-β) and insulin resistance (HOMA-IR), and also insulin sensitivity index (BIGTT-SI) and acute insulin response (BIGTT-AIR), were calculated. Subgroup analyses were performed in those with: (1) double verification of BW difference; (2) difference in BW >0.5 kg; and (3) no overt metabolic disease (type 2 diabetes, hyperlipidaemia or thyroid disease).
  
  
  RESULTS
  No intra-pair differences in p-glucose, insulin, C-peptide, incretin hormones, HOMA-β, HOMA-IR or BIGTT-SI were identified. p-Glucose at 120 min was higher in the twins with the highest BW without metabolic disease, and BIGTT-AIR was higher in those with the highest BW although not in pairs with a BW difference of >0.5 kg.
  
  
  CONCLUSIONS
  BW-discordant MZ twins provide no evidence for a detrimental effect of low BW on glucose metabolism in adulthood once genetic factors and rearing environment are controlled for.
authors.affiliation: The Danish Twin Registry, Department of Epidemiology, University of Southern Denmark, JB Winsløvsvej 9, Odense C, Denmark. frostnielsen@yahoo.com
authors.forename: M
authors.initials: M
authors.lastname: Frost
authors.forename: I
authors.initials: I
authors.lastname: Petersen
authors.forename: K
authors.initials: K
authors.lastname: Brixen
authors.forename: H
authors.initials: H
authors.lastname: Beck-Nielsen
authors.forename: J J
authors.initials: JJ
authors.lastname: Holst
authors.forename: L
authors.initials: L
authors.lastname: Christiansen
authors.forename: K
authors.initials: K
authors.lastname: Højlund
authors.forename: K
authors.initials: K
authors.lastname: Christensen
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001724:Birth Weight; D001786:Blood Glucose / Q000378:metabolism*; D002096:C-Peptide / Q000097:blood*; D003718:Denmark / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000453:epidemiology; D004198:Disease Susceptibility / Q000097:blood* / Q000453:epidemiology; D005260:Female; D052216:Glucagon-Like Peptide 1 / Q000097:blood*; D018149:Glucose Intolerance; D005951:Glucose Tolerance Test; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007333:Insulin Resistance; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014430:Twins, Monozygotic
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D052216:Glucagon-Like Peptide 1