Red cell distribution width, haemoglobin A1c and incidence of diabetes mellitus.
OBJECTIVE
Hyperglycaemia has multiple effects on the red blood cell (RBC), including glycation of haemoglobin, reduced deformability and reduced lifespan. Red cell distribution width (RDW) is a measure of the heterogeneity of erythrocyte volumes. The aim of this study was to explore the relationships between RDW and glucose, haemoglobin A1c (HbA1c) and incidence of diabetes mellitus (DM).


METHODS
RDW and mean corpuscular volume were measured in 26 709 non-diabetic participants (aged 45-73 years) from the population-based Malmö Diet and Cancer cohort. HbA1c and fasting venous blood glucose levels were measured in 4845 subjects.


METHODS
Incidence of DM (n = 2944) over 14 years of follow-up was studied by linkage with national and local DM registers.


RESULTS
Individuals with low RDW had significantly higher risk of developing DM [adjusted hazard ratio (HR) 1.48, 95% confidence interval (CI) 1.29-1.70, for 1st vs. 4th quartile], especially in subjects with impaired fasting glucose (n = 416) (HR 2.15, 95% CI 1.12-4.14). Low RDW was also associated with significantly higher waist circumference and glucose, insulin and triglyceride concentrations. By contrast, RDW was significantly and positively associated with HbA1c, corresponding an increase in HbA1c of 0.10% per 1 SD increase in RDW.


CONCLUSIONS
Low RDW is associated with increased incidence of DM independently of other risk factors. We propose that low RDW could be a surrogate marker of reduced RBC survival, with lower HbA1c due to shorter duration of glucose exposure. RDW is a biomarker that could improve risk assessment for individuals at risk of developing DM.
Department of Clinical Sciences, Lund University, Malmö, Sweden.
G
G
Engström
J G
JG
Smith
M
M
Persson
P M
PM
Nilsson
O
O
Melander
B
B
Hedblad
D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D003920:Diabetes Mellitus / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D004906:Erythrocyte Count; D004909:Erythrocyte Indices; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D015994:Incidence; D008297:Male; D008498:Medical Record Linkage; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D055105:Waist Circumference
D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin
HbA1c; diabetes; epidemiology; erythrocytes; glucose