UVR protection influences fructosamine level after sun exposure of healthy adults

Background: Seasonal variation in glycated hemoglobin levels has been observed, and sun exposure has been considered as one of the factors associated with this relationship. Fructosamine is a short-time marker of blood protein glycation. Aim: We investigated the effect of seven days of sunbathing on blood fructosamine concentration in healthy volunteers using different ultraviolet radiation (UVR) protections. Materials and Methods: Participants were assigned to one of three groups: group A – used a UVA and UVB absorbing sunscreen (N = 15), group B – used a UVB absorbing sunscreen (N = 18), and group C – followed uncontrolled sun protection habits (N = 22). Results: Overall, the fructosamine concentration did not change after sun exposure (baseline 248.8 μmol/l, 25–75%: 238.5 to 258.8 μmol/l vs. after 247.3 μmol/l, 25–75%: 234.9 to 261.8 μmol/l, P = 0.6637). Median change of fructosamine differed significantly between groups (A: −1.90 μmol/l, 25–75%: −17.10 to 1.80 μmol/l vs. B: −3.80 μmol/l, 25–75%: −18.50 to 2.40 μmol/l vs. C: +4.05 μmol/l, 25–75%: −3.20 to 22.0 μmol/l; one-way ANOVAP = 0.0277). After age adjustment and combining groups A and B, the difference in change of fructosamine concentration was statistically significant between groups A + B (decrease) vs. group C (increase, P = 0.0193). Conclusion: Appropriate sunscreen use during sunbathing resulted in decreased fructosamine concentrations, while inadequate UVR protection resulted in its increase.