Introduction: Adult body mass index (BMI) is strongly associated with venous thromboembolism (VTE), however whether earlier-life adiposity or other measures of adult adiposity are associated with VTE risk remains unknown.
Hypothesis: Since BMI is a strong risk factor for incident VTE, we hypothesized that early life body size as well as other measures of adult adiposity may also be positively associated with VTE risk.
Methods: We evaluated associations of childhood somatotype, BMI at age 18, change in BMI since age 18, and measures of waist and hip circumference with incident VTE among 47,415 women age 40-67 years at baseline from the Nurses’ Health Study (NHS), 47,539 women age 29-48 years from the Nurses’ Health Study II (NHS II), and 32,707 men age 39-76 years from the Health Professionals Follow-Up Study (HPFS) without a prior VTE. We calculated multivariable-adjusted hazard ratios (HR) of VTE using Cox proportional hazards models.
Results: Over ≥25 years of follow-up, there were 1,191 incident VTE cases in NHS, 763 cases in NHS II, and 1,350 cases in HPFS. Adult BMI was strongly associated with VTE in all three cohorts (HRs comparing ≥35 kg/m2 vs. <22.5 kg/m2: NHS: 3.03 [95% CI: 2.58, 3.55], NHS II: 3.88 [95% CI: 3.36, 4.48], HPFS: 2.49 [95% CI: 1.83, 3.29]; all Ptrend<0.01). Waist circumference, hip circumference, and height were associated with greater VTE risk, even after adjusting for adult BMI (all Ptrend<0.01) (Table). Somatotype at ages 5 and 10, BMI at age 18, and change in BMI since age 18 were not significantly associated with VTE risk, after accounting for adult BMI.
Conclusions: Adult BMI, waist circumference, hip circumference, and height were independently, positively associated with incident VTE risk. Early life body size was not significantly associated with VTE risk after accounting for adult BMI, indicating that BMI and adiposity are likely more important acutely that cumulatively over time in the etiology of VTE. Clinically, encouraging weight loss in adults