Association of erythrocyte indices with glycated haemoglobin in pre-menopausal women.

Aims  Although HbA1c is known to be affected by the lifespan of erythrocytes, any association of erythrocyte indices with HbA1c in subjects without anaemia is poorly understood. Pre-menopausal women may be relatively iron deficient because of menstruation. In this study, we examined the relationship between HbA1c and erythrocyte indices in pre- and post-menopausal women. Methods  We determined HbA1c, red blood cell (RBC) count, haematocrit, haemoglobin, mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH) in 423 women with normal glucose tolerance who had undergone health checks. In addition, age at menopause was recorded in post-menopausal subjects. Results  RBC counts of the 180 pre-menopausal women were positively associated with HbA1c, whereas haemoglobin, MCV and MCH showed a negative association. In contrast, no significant association of any indices with HbA1c was detected in the 243 post-menopausal women. Stepwise multivariate regression analysis in the pre-menopausal women identified fasting plasma glucose and age as positively associated and MCH as negatively associated with HbA1c, regardless of whether or not these pre-menopausal women were anaemic. Conclusions  Erythrocyte indices are associated with HbA1c, independently of plasma glucose levels, in pre-menopausal women even when they are not anaemic. This should be appreciated when interpreting HbA1c in pre-menopausal patients with diabetes.