Effect of obesity and physical activity on D‐dimer – A Randomized controlled study in Adolescents

We studied the effects of obesity and physical activity on D‐dimer (DD), a marker of increased turnover of intravascular cross‐linked fibrin, in children and its relationship with fibrinolytic factors, fibrinogen & fibrinogen fractional synthetic rate (FSR) in 21 children (15 obese and 6 lean;Tanner stage, IV–V). Obese subjects underwent a 3‐month randomized controlled physical activity‐based intervention. New data show that the higher DD levels in obese vs. lean controls (112.3±11.8 vs. 63.7±12.9 ng/mL; p=0.02) were reduced after the intervention (p<0.01). We previously reported that fibrinogen levels and FSR decreased (p<0.01), while fibrinolytic factors were unaffected by the intervention. Parallel reductions in DD and fibrinogen levels and the FSR of fibrinogen after intervention indicated a putative decrease in the production and availability of fibrinogen for fibrin formation, thus ‘indirectly’ lowering DD, the primary degradation product of fibrin. The lack of change in fibrinolysis reflects a lack of degradation of preexistent fibrin, but may also argue against generation of new fibrin from fibrinogen representing a potentially beneficial change in coagulation function. Therefore, it appears that despite depressed fibrinolysis, the balance between coagulation and fibrinolysis was maintained after intervention suggesting a state of overall lower atherogenesity.