Washington State University Spokane Health Sciences, 412 E Spokane Falls Blvd, Spokane, WA 99202, USA.
Washington State University Spokane Health Sciences, 412 E Spokane Falls Blvd, Spokane, WA 99202, USA.
Spine J. 2020 Nov;20(11):1805-1815. doi: 10.1016/j.spinee.2020.06.017. Epub 2020 Jun 29.
Low back pain (LBP) is a common and significant cause of disability worldwide, however; questions about cause still remain.
To investigate the association between LBP, body mass index (BMI), and moderate to vigorous physical activity (MVPA) in a twin sample.
Cross sectional study of monozygotic (MZ) and dizygotic (DZ) twins from the Washington State Twin Registry.
Monozygotic and dizygotic twins from the Washington State Twin Registry.
Self-report measures: Low back pain, body mass index, duration and intensity of exercise.
The sample included 5,183 same-sex pairs (69% MZ). The outcome was self-reported diagnosis of LBP from a health care provider. A phenotypic model tested the association between BMI and LBP without including genetic or shared environmental confounds. We then re-estimated the association using a quasi-causal model which controls for those confounds. Finally, we used a mediation model to investigate if the association between LBP and MVPA was mediated by BMI.
In the phenotypic regression of LBP on BMI, there was a ~4-fold increase in the odds of having LBP with every one-unit increase in BMI (odds ratio [OR] =3.83; 95% confidence interval =3.28, 4.46). However, quasi-causal regression of LBP on BMI was reduced to zero (OR =0.95; 95% confidence interval =0.60, 1.49). A significant genetic background to BMI and LBP was present (b =1.66; p<.001), even after controlling for confounders. In another analysis there was a significant direct effect between MVPA and LBP (b=-0.092, standard error [SE] =0.017, p<.001). In mediation analysis, the effect of MVPA on LBP was partially mediated through MVPA effects on BMI ( [Formula: see text] =-0.043, SE=0.003, p<.001) and BMI effects on LBP ( [Formula: see text] =1.281, SE=0.079, OR=3.6, p<.001), however shared environmental factors confounded this relationship.
BMI was not associated with LBP, despite sharing a phenotypic association, but they may share a genetic influence. The effect of MVPA on LBP is, in part, mediated by BMI but shared environment confounds this relationship.
Level 3.
下腰痛（LBP）是全世界常见且严重的致残原因，但病因仍存在疑问。
在双胞胎样本中研究 LBP、体重指数（BMI）和中等到剧烈体力活动（MVPA）之间的关联。
来自华盛顿州双胞胎登记处的同卵（MZ）和异卵（DZ）双胞胎的横断面研究。
来自华盛顿州双胞胎登记处的同卵和异卵双胞胎。
自我报告的测量：下腰痛、体重指数、运动的持续时间和强度。
该样本包括 5183 对同性双胞胎（69% MZ）。下腰痛的结果是由医疗保健提供者自报的诊断。表型模型测试了 BMI 与 LBP 之间的关联，而不包括遗传或共同环境混杂因素。然后，我们使用准因果模型重新估计了关联，该模型控制了这些混杂因素。最后，我们使用中介模型来研究 LBP 和 MVPA 之间的关联是否通过 BMI 介导。
在 LBP 对 BMI 的表型回归中，BMI 每增加一个单位，LBP 的几率增加约 4 倍（优势比 [OR] =3.83；95%置信区间 [CI] =3.28, 4.46）。然而，LBP 对 BMI 的准因果回归减少到零（OR =0.95；95%CI =0.60, 1.49）。BMI 和 LBP 存在显著的遗传背景（b =1.66；p<.001），即使在控制了混杂因素之后也是如此。在另一项分析中，MVPA 与 LBP 之间存在显著的直接效应（b=-0.092，标准误差 [SE] =0.017，p<.001）。在中介分析中，MVPA 对 LBP 的影响部分通过 MVPA 对 BMI 的影响（ [Formula: see text] =-0.043，SE=0.003，p<.001）和 BMI 对 LBP 的影响（ [Formula: see text] =1.281，SE=0.079，OR=3.6，p<.001）介导，但共同环境因素使这种关系复杂化。
尽管存在表型关联，但 BMI 与 LBP 无关，但它们可能具有遗传影响。MVPA 对 LBP 的影响部分通过 BMI 介导，但共同环境因素使这种关系复杂化。
3 级。
