Institute of Environmental Medicine, Karolinska Institutet, Nobels väg 13, 17177, Stockholm, Sweden.
Centre for Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden.
BMC Med. 2022 Aug 12;20(1):240. doi: 10.1186/s12916-022-02447-5.
Maternal smoking during pregnancy was reported to be associated with a reduced risk of type 1 diabetes in the offspring. We investigated whether this association is consistent with a causal interpretation by accounting for familial (shared genetic and environmental) factors using family-based, quasi-experimental designs.
We included 2,995,321 children born in Sweden between 1983 and 2014 and followed them for a diagnosis of type 1 diabetes until 2020 through the National Patient, Diabetes and Prescribed Drug Registers. Apart from conducting a traditional cohort study, we performed a nested case-control study (quasi-experiment) comparing children with type 1 diabetes to their age-matched siblings (or cousins). Information on maternal smoking during pregnancy was retrieved from the Swedish Medical Birth Register. Multivariable adjusted Cox proportional hazards regression and conditional logistic regression were used.
A total of 18,617 children developed type 1 diabetes, with a median age at diagnosis of 9.4 years. The sibling and cousin comparison design included 14,284 and 7988 of these children, respectively. Maternal smoking during pregnancy was associated with a 22% lower risk of offspring type 1 diabetes in the full cohort (hazard ratio 0.78, 95% confidence interval [CI] 0.75-0.82). The corresponding odds ratio was 0.78 (95% CI 0.69-0.88) in the sibling and 0.72 (95% CI 0.66-0.79) in the cousin comparison analysis.
This nationwide, family-based study provides support for a protective effect of maternal smoking on offspring type 1 diabetes. Mechanistic studies are needed to elucidate the underlying pathways behind this link.
有研究报道称，母亲在怀孕期间吸烟与后代患 1 型糖尿病的风险降低有关。我们通过基于家庭的准实验设计，利用家族（共享遗传和环境）因素来研究这种关联是否与因果关系一致。
我们纳入了 1983 年至 2014 年间在瑞典出生的 2995321 名儿童，并通过国家患者、糖尿病和处方药物登记处对他们进行随访，直至 2020 年诊断出 1 型糖尿病。除了进行传统的队列研究外，我们还进行了嵌套病例对照研究（准实验），将患有 1 型糖尿病的儿童与他们年龄匹配的兄弟姐妹（或表兄弟姐妹）进行比较。母亲在怀孕期间吸烟的信息从瑞典医学出生登记处获取。采用多变量调整的 Cox 比例风险回归和条件逻辑回归进行分析。
共有 18617 名儿童确诊为 1 型糖尿病，中位诊断年龄为 9.4 岁。在这项研究中，同胞和表亲比较设计分别纳入了其中 14284 名和 7988 名儿童。在全队列中，母亲在怀孕期间吸烟与子女患 1 型糖尿病的风险降低 22%相关（风险比 0.78，95%置信区间 [CI] 0.75-0.82）。在同胞比较和表亲比较分析中，相应的比值比分别为 0.78（95% CI 0.69-0.88）和 0.72（95% CI 0.66-0.79）。
这项全国性的基于家庭的研究为母亲在怀孕期间吸烟对子女 1 型糖尿病的保护作用提供了支持。需要进行机制研究来阐明这种关联背后的潜在途径。
