Background Circulating levels of leptin, an adipocyte-derived hormone, are frequently elevated in obesity. Leptin has been reported to upregulate prothrombotic hemostatic factors in vitro and could potentially mediate venous thromboembolism (VTE) risk in obesity. However, whether leptin is associated with VTE remains uncertain.

Objective This article investigates the association between plasma leptin and risk of incident VTE, and the potential of leptin to mediate VTE risk in obesity.

Methods A population-based nested case–control study with 416 VTE cases and 848 age- and sex-matched controls was derived from the Tromsø Study. Logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) for VTE across leptin quartiles. Analyses were performed separately in men and women using sex-specific quartile cut-offs determined in controls.

Results In the age-adjusted model, the VTE risk increased across leptin quartiles, particularly in men. Compared with the lowest quartile, the ORs for VTE in the highest quartile were 1.70 (95% CI 1.04–2.79) in men and 1.36 (95% CI 0.85–2.17) in women. However, with additional adjustment for body mass index (BMI), risk estimates were markedly attenuated in men (OR 1.03, 95% CI 0.55–1.93) and women (OR 0.82, 95% CI 0.45–1.48). The ORs for VTE were increased in obese men and women (BMI ≥ 30 kg/m²) and were only marginally affected after adjustment for leptin.

Conclusion Our results indicate that the apparent association between plasma leptin levels and VTE risk is confounded by BMI and that leptin is not a relevant mediator for VTE risk in obesity.

背景 瘦素（一种脂肪细胞衍生激素）的循环水平在肥胖症中经常升高。据报道，瘦素在体外可上调促血栓形成止血因子，并可能潜在地介导肥胖患者的静脉血栓栓塞 (VTE) 风险。然而，瘦素是否与 VTE 相关仍不确定。

目的 本文探讨血浆瘦素与 VTE 风险之间的关系，以及瘦素介导肥胖患者 VTE 风险的潜力。

方法 来自 Tromsø 研究的基于人群的巢式病例对照研究包含 416 例 VTE 病例和 848 例年龄和性别匹配的对照。Logistic 回归用于计算 VTE 跨瘦素四分位数的 95% 置信区间 (CI) 的优势比 (OR)。使用在对照中确定的性别特异性四分位数截止值分别在男性和女性中进行分析。

结果 在年龄调整模型中，VTE 风险在瘦素四分位数中增加，特别是在男性中。与最低四分位数相比，最高四分位数 VTE 的 OR 为男性 1.70（95% CI 1.04-2.79）和女性 1.36（95% CI 0.85-2.17）。然而，随着体重指数 (BMI) 的额外调整，男性 (OR 1.03, 95% CI 0.55–1.93) 和女性 (OR 0.82, 95% CI 0.45–1.48) 的风险估计值显着降低。^{肥胖男性和女性（BMI ≥ 30 kg/m 2} ）的 VTE ORs 增加，并且在调整瘦素后仅受到轻微影响。

结论 我们的结果表明，血浆瘦素水平与 VTE 风险之间的明显关联被 BMI 混淆了，并且瘦素不是肥胖患者 VTE 风险的相关介质。