title: Molecularly-defined lactose malabsorption, milk consumption and anthropometric differences in adult males.
abstract: BACKGROUND
  Lactose malabsorption (LM) may be associated with reduced skeletal calcium content. Diagnosis to date has been based on indirect methods, with a high false-negative rate. Identification of the LCT polymorphism led to development of a PCR-based test.
  
  
  OBJECTIVE
  To evaluate the PCR-based test compared to a combination the hydrogen breath test and the lactose tolerance test, and investigate anthropometrical differences, changes in bone mineral density and oral calcium intake according to LCT polymorphism and milk-drinking habits.
  
  
  METHODS
  All participants (n = 278) underwent clinical examination, with measurement of height, weight and bone density (DXA), and were genotyped for LCT polymorphism (LCT CC or LCT TT: CC is associated with LM). A subgroup (n = 51) had a hydrogen breath test and a lactose tolerance test, in addition to genotyping.
  
  
  RESULTS
  Detection of LM by LCT polymorphism was highly significant (p = 0.001). The correlation between LCT genotype and self-reported milk-intolerance or dislike of milk with was slight, but the correlation with functional tests was highly significant. Non-milk-drinkers were lighter (-5 kg) and significantly shorter (-4 cm) than milk-drinkers (p = 0.07 and 0.04, respectively). Total calcium consumption was lower among non-milk-drinkers by about 18% (p = 0.03).
  
  
  CONCLUSIONS
  Genotyping is an economic, quick and convenient method for diagnosing lactose malabsorption, with results comparable to existing tests. Sufficient calcium consumption may be relevant to body growth, as milk-drinkers were taller. Negative calcium bone balance may be prevented when provision is made for adequate calcium intake.
authors.affiliation: Division of Endocrinology and Nuclear Medicine, Department of Internal Medicine, Medical University Hospital, Auenbruggerplatz 15, A-8036 Graz, Austria. markus.gugatschka@klinikum-graz.at
authors.forename: M
authors.initials: M
authors.lastname: Gugatschka
authors.forename: H
authors.initials: H
authors.lastname: Dobnig
authors.forename: A
authors.initials: A
authors.lastname: Fahrleitner-Pammer
authors.forename: P
authors.initials: P
authors.lastname: Pietschmann
authors.forename: S
authors.initials: S
authors.lastname: Kudlacek
authors.forename: A
authors.initials: A
authors.lastname: Strele
authors.forename: B
authors.initials: B
authors.lastname: Obermayer-Pietsch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology; D001944:Breath Tests / Q000379:methods; D002136:Calcium, Dietary / Q000008:administration & dosage; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics; D004326:Drinking / Q000502:physiology; D005838:Genotype; D006801:Humans; D006859:Hydrogen / Q000032:analysis; D007787:Lactose Intolerance / Q000175:diagnosis* / Q000235:genetics; D007789:Lactose Tolerance Test / Q000379:methods / Q000592:standards; D008297:Male; D008875:Middle Aged; D008892:Milk; D016133:Polymerase Chain Reaction / Q000379:methods / Q000592:standards*; D011110:Polymorphism, Genetic; D012680:Sensitivity and Specificity
chemical_list: D002136:Calcium, Dietary; D006859:Hydrogen