Background: The aim of this study was to quantify the relationship between insulin resistance and haematological parameters from adolescence to adulthood.
Methods: Participants from the EPITeen cohort were evaluated at 13, 17, and 21 years, through standardized procedures. A fasting blood sample was obtained, and insulin resistance was evaluated by the homeostatic model assessment (HOMA-IR). The cross-sectional association between HOMA-IR and haematological parameters at 21 years was quantified in 1671 participants by multivariate linear regression coefficients (β) and 95% confidence intervals (95%CI). For the longitudinal analysis (n = 496), trajectories of insulin and glucose were estimated using model-based clustering, and haematological parameters were compared according to trajectories using ANOVA.
Results: At 21 years, after adjustment for BMI, positive associations (β [95%CI]) were found between HOMA-IR and red blood count (0.05 [0.03;0.07] in females; 0.02 [0.00;0.04] in males); and haematocrit (0.29 [0.12;0.46] in females; 0.21 [0.04,0.38] in males). In females, HOMA-IR was inversely associated with packed cell volume (PCV) (-0.35 [-0.66;-0.05]) and iron levels (-3.98 [-6.94,-1.03]) but positively associated with white blood cells (0.31 [0.19;0.43]) and platelets (7.66 [3.93;11.39]). In males, a higher HOMA-IR was significantly associated with higher haemoglobin (0.09 [0.03;0.16]). Regarding the longitudinal analysis, similar trends were found, but statistical significance was not reached.
Conclusions: Both longitudinal and cross-sectional analyses support the hypothesis that insulin resistance is associated with increased red blood cells count and haematocrit in young adults, even within normal ranges of insulin and glucose.
Keywords: HOMA-IR; adolescent; adulthood; haematocrit; insulin resistance; red blood cells.
© 2019 John Wiley & Sons, Ltd.