An investigation of sickle cell trait, body mass index, and fitness in relation to venous thromboembolism among African American adults

Background: The relationships of sickle cell trait (SCT), body mass index (BMI), and physical fitness to venous thromboembolism (VTE) in young adults have received little attention. Objectives: To test for associations among SCT, BMI, fitness, and VTE. Patients/Methods: We conducted a retrospective cohort study of 48,316 SCT-tested, African American individuals in the US Army during 2011–14. We used Cox proportional hazards models to compute adjusted hazards of deep vein thrombosis (DVT) and pulmonary embolism (PE) associated with selected factors. Results: Incidence rates of DVT and PE were 1.09 and 0.91 cases per 1000 person-years, respectively. Adjusted hazard ratios (aHRs) for DVT for men and women with SCT were 0.9 (95% confidence interval [CI]: 0.4–2.0; P =.711) and 1.51 (CI: 0.7–3.2; P =.274), respectively. aHRs for PE for SCT+ men and women were 1.1 (CI: 0.5–2.4; P =.773) and 1.2 (CI: 0.5–3.1; P =.650), respectively. Low physical fitness was associated with DVT and PE in women (DVT aHR =3.1; CI: 1.4–6.5; P =.004; PE aHR =4.6; CI: 2.1–9.9; P <.001) and DVT in men (aHR =2.2; CI: 1.0–4.6; P =.048). Recent weight gain of 1 or more BMI points was associated with DVT in men (aHR =1.8; CI: 1.1–2.8; P =.017). Conclusions: We found no evidence of increased VTE risk associated with SCT in this population. However, lower fitness levels and BMI increases were so associated.