Objective Obesity is an important venous thrombosis (VT) risk factor but the reasons for this are unclear. Materials and methods In a cohort of 20,914 individuals aged 45 and older without prior VT, we calculated the relative risk (RR) of VT over 12.6 years follow-up according to baseline body size measures, and studied whether associations were mediated by biomarkers of hemostasis and inflammation that are related to adiposity. Results Greater levels of all body size measures (weight, height, waist, hip circumference, calf circumference, body-mass index, waist-hip ratio, fat mass and fat-free mass) were associated with increased risk of VT, with 4th versus 1st quartile RRs of 1.5-3.0. There were no multiplicative interactions of biomarkers with obesity status. Adjustment for biomarkers associated with VT risk and body size (factors VII and VIII, von Willebrand factor, partial thromboplastin time, D-dimer, C-reactive protein and factor XI) only marginally lowered, or did not impact, the RRs associated with body size measures. Conclusions Greater body size, by multiple measures, is a risk factor for VT. Associations were not mediated by circulating levels of studied biomarkers suggesting that body size relates to VT because of physical factors associated with blood flow, not the hypercoagulability or inflammation associated with adiposity.
Bibliographical noteFunding Information:
ARIC is carried out as a collaborative study supported by the National Heart, Lung, and Blood Institute (NHLBI) contracts HHSN268201100005C, HHSN268201100006C, HHSN268201100007C, HHSN268201100008C, HHSN268201100009C, HHSN268201100010C, HHSN268201100011C, and HHSN268201100012C. CHS was supported by contracts HHSN268201200036C, HHSN268200800007C, N01 HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, N01HC85086, and grant HL080295 from the NHLBI, with additional contribution from the National Institute of Neurological Disorders and Stroke (NINDS) and AG023629 from the National Institute on Aging (NIA). The Longitudinal Investigation of Thromboembolism Etiology was funded by R01-HL59367. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The funding source had no role in the study design, manuscript writing or decision to publish.
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- Abbreviations ARIC Atherosclerosis Risk in Communities
- BMI body-mass index
- CHS Cardiovascular Health Study
- VT venous thrombosis