The effect of aspirin and vitamins C and E on HbA1c assays.
BACKGROUND
Aspirin (ASA) and vitamins C and E may inhibit non-enzymatic glycation in vivo and may also interfere with HbA(1c) assays, masking true results. We investigated the effect of usual doses of ASA, vitamin C and E on HbA1c levels in a group of non-diabetic volunteers.


METHODS
A randomized clinical trial was performed with 28 healthy non-diabetic individuals. Subjects were allocated to take ASA 200 mg/day, vitamin C 1 g/day, vitamin E 400 mg/day, or to a control group, for a period of 4 months. Blood samples were collected at baseline and at monthly intervals for HbA1c analysis by HPLC Variant II (BioRad), HPLC L-9100 (Merck - Hitachi) and Tina Quant HbA(1c) II immunoassay (Roche).


RESULTS
HbA(1c) levels of the control, vitamin C and E groups did not change throughout the study, independently of the method used. HbA(1c) measured by Hitachi L-9100 HPLC increased significantly (P=0.033) at 4 months after ASA intake, although this increase was of only 0.17%.


CONCLUSIONS
Treatment with vitamins C and E in pharmacological doses does not have any impact on HbA1c measurements in non-diabetic patients with the three methods employed. ASA induces a modest, not clinically relevant, increase in HbA1c levels with one of the methods.
Camargo
Joíza L
JL
Clinical Pathology Department, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil. jcamargo@hcpa.ufrgs.br
Stifft
Jonathas
J
Gross
Jorge L
JL
D001205:Ascorbic Acid / Q000494:pharmacology*; D001241:Aspirin / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D014810:Vitamin E / Q000494:pharmacology*
D001205:Ascorbic Acid; D001241:Aspirin; D006442:Glycated Hemoglobin; D014810:Vitamin E