Serum diamine oxidase activity is associated with lactose malabsorption phenotypic variation.
OBJECTIVE
Recently, an intermediate lactose intolerance (LI) phenotype based on the lactase gene (LCT) C/T-13910polymorphism was proposed. However, a multifactorial genesis of LI phenotypic variation including endogenous and exogenous factors cannot be ruled out. Therefore, this study was conducted to investigate a possible association between serum diamine oxidase (DAO) and LI phenotypes in individuals with lactose malabsorption (LM).


METHODS
A total of 121 ambulatory patients with LM were included in this retrospective study. The lactose hydrogen breath test (LHBT) and serum DAO activity measurements were performed on the same day. A thorough anamnesis with respect to gastrointestinal symptoms was carried out at the initial consultation.


RESULTS
In total, 44 (36.4%) patients with a serum DAO activity <10U/mL showed higher H2levels after 60 (mean: 53.7±57.6 vs 34.5±31.7 parts per million [ppm], p=0.116), 90 (mean: 70.3±57.5 vs 52.7±41.4ppm, p=0.184) and 120min (mean: 98.9±72.5 vs 67.9±44.9ppm, p=0.012) during LHBT compared to 77 (63.6%) patients with a serum DAO activity ≥10U/mL. Individuals with a serum DAO activity <10U/mL tended to report gastrointestinal symptoms during the LHBT more often (p=0.091).


CONCLUSIONS
Our findings suggest that patients with LM and a serum DAO activity level<10U/mL had higher end-expiratory H2levels and tended to be more symptomatic during the LHBT compared to LM patients with DAO activity levels ≥10U/mL.
Institute of Clinical Chemistry and Laboratory Medicine, General Hospital Steyr, Sierningerstraße 170, 4400 Steyr, Austria; Clinical Institute of Medical and Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria. Electronic address: dietmar.enko@gespag.at.
Dietmar
D
Enko
Institute of Clinical Chemistry and Laboratory Medicine, General Hospital Steyr, Sierningerstraße 170, 4400 Steyr, Austria; Clinical Institute of Medical and Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria. Electronic address: gernot.kriegshaeuser@gespag.at.
Gernot
G
Kriegshäuser
Institute of Clinical Chemistry and Laboratory Medicine, General Hospital Steyr, Sierningerstraße 170, 4400 Steyr, Austria. Electronic address: gabriele.baumann@gespag.at.
Gabriele
G
Halwachs-Baumann
Clinical Institute of Medical and Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria. Electronic address: harald.mangge@medunigraz.at.
Harald
H
Mangge
Practice for General Internal Medicine, Dr. Theodor-Körner-Straße 19b, 8600 Bruck an der Mur, Austria. Electronic address: w.schnedl@dr.schnedl.at.
Wolfgang J
WJ
Schnedl
D000328:Adult; D006631:Amine Oxidase (Copper-Containing) / Q000097:blood*; D005260:Female; D006801:Humans; D007787:Lactose Intolerance; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D012189:Retrospective Studies
D006631:Amine Oxidase (Copper-Containing)
Breath test; Diamine oxidase; Lactose intolerance; Phenotypes