Department of Epidemiology, Human Genetics and Environmental Sciences, UTHealth School of Public Health, Houston, Texas.
Texas Department of State Health Services, Birth Defects Epidemiology and Surveillance Branch, Austin, Texas.
Birth Defects Res. 2019 Nov 1;111(18):1389-1398. doi: 10.1002/bdr2.1547. Epub 2019 Jul 10.
Epidemiologic studies have consistently identified an association between spina bifida and maternal body mass index (BMI). Whether this reflects a causal relationship is unknown. If this association does reflect a causal relationship, the risk of spina bifida should change with changes in maternal BMI. We evaluated the association between spina bifida and maternal change in BMI, assessed using interpregnancy change in BMI (IPC-BMI).
We used data from the Texas Birth Defects Registry and statewide vital records for 248 spina bifida cases and 2,562 controls (2006-2012) to conduct a case-control study. We used logistic regression to estimate the association between IPC-BMI and spina bifida, with adjustment for potential confounders.
When assessed as a continuous variable, IPC-BMI was associated with spina bifida, with a 5% increase in the odds of spina bifida per unit (approximately 6 pounds) increase in BMI (adjusted odds ratios [aOR] = 1.05, 95% CI: 1.02, 1.09). When assessed as a categorical variable, with weight stable women as the referent, the odds of spina bifida were lower in women with any BMI decrease (aOR = 0.73, 95% CI: 0.50, 1.08) and higher in women with an increase of ≥1 BMI units (aOR = 1.17, 95% CI: 0.85, 1.62).
Our findings provide suggestive, although not conclusive, evidence that maternal prepregnancy change in BMI, assessed using IPC-BMI, is associated with spina bifida in the later pregnancy. Additional studies aimed at confirming this association and further strengthening the evidence for a causal relationship between spina bifida and maternal BMI are needed.
流行病学研究一致表明，脊柱裂与母体体重指数（BMI）之间存在关联。但这种关联是否反映了因果关系尚不清楚。如果这种关联确实反映了因果关系，那么脊柱裂的风险应该会随着母体 BMI 的变化而变化。我们评估了脊柱裂与母体 BMI 变化之间的关联，采用的是妊娠间 BMI 变化（IPC-BMI）来评估。
我们利用得克萨斯州出生缺陷登记处和全州范围的生命记录数据，对 248 例脊柱裂病例和 2562 例对照（2006-2012 年）进行了病例对照研究。我们使用逻辑回归来估计 IPC-BMI 与脊柱裂之间的关联，并对潜在混杂因素进行了调整。
当作为连续变量进行评估时，IPC-BMI 与脊柱裂相关，BMI 每增加一个单位（约 6 磅），脊柱裂的几率增加 5%（调整后的比值比[aOR] = 1.05，95%CI：1.02，1.09）。当作为分类变量进行评估时，以体重稳定的女性为参照，BMI 降低的女性脊柱裂的几率降低（aOR = 0.73，95%CI：0.50，1.08），BMI 增加≥1 个单位的女性脊柱裂的几率升高（aOR = 1.17，95%CI：0.85，1.62）。
我们的研究结果提供了提示性但非结论性的证据，表明使用 IPC-BMI 评估的母体妊娠前 BMI 变化与后期妊娠的脊柱裂有关。需要进一步开展研究来证实这种关联，并进一步加强脊柱裂与母体 BMI 之间因果关系的证据。
