Maternal Smoking and Metabolic Health Biomarkers in Newborns

Background
Maternal smoking has been associated with elevated risk of type 2 diabetes among the offspring in adulthood. The mechanisms underlying this fetal “programming” effect remain unclear. The present study sought to explore whether maternal smoking affects metabolic health biomarkers in fetuses/newborns.
Methods
In a prospective singleton pregnancy cohort (n = 248), we compared metabolic health biomarkers in the newborns of smoking and non-smoking mothers. Outcomes included cord plasma insulin, proinsulin, insulin-like growth factor I (IGF-I), IGF-II, leptin and adiponectin concentrations, glucose-to-insulin ratio (an indicator of insulin sensitivity) and proinsulin-to-insulin ratio (an indicator of β-cell function).
Results
Independent of maternal (glucose tolerance, age, ethnicity, parity, education, body mass index, alcohol use) and infant (sex, gestational age, birth weight z score, mode of delivery, cord blood glucose concentration) characteristics, the newborns of smoking mothers had lower IGF-I concentrations (mean: 6.7 vs. 8.4 nmol/L, adjusted p = 0.006), and marginally higher proinsulin-to-insulin ratios (0.94 vs. 0.72, adjusted p = 0.06) than the newborns of non-smoking mothers. Cord plasma insulin, proinsulin, IGF-II, leptin and adiponectin concentrations and glucose-to-insulin ratios were similar in the newborns of smoking and non-smoking mothers.
Conclusions
Maternal smoking was associated with decreased fetal IGF-I levels, and borderline lower fetal β-cell function. Larger cohort studies are required to confirm the latter finding. The preliminary findings prompt the hypothesis that these early life metabolic changes may be involved in the impact of maternal smoking on future risk of metabolic syndrome related disorders in the offspring.

研究背景
母体吸烟与子代成年后2型糖尿病发病风险升高存在关联，但其介导这一胎儿编程效应（fetal programming）的具体机制仍不明确。本研究旨在探究母体吸烟是否会影响胎儿/新生儿的代谢健康生物标志物水平。

研究方法
本研究纳入一项单胎妊娠前瞻性队列（n=248），对比吸烟母亲与非吸烟母亲所产新生儿的代谢健康生物标志物水平。检测指标包括脐带血浆胰岛素、胰岛素原、胰岛素样生长因子I（IGF-I）、IGF-II、瘦素与脂联素浓度，以及葡萄糖-胰岛素比值（胰岛素敏感性指标）与胰岛素原-胰岛素比值（β细胞功能指标）。

研究结果
在校正母体因素（葡萄糖耐量、年龄、种族、产次、受教育程度、体质量指数、饮酒情况）与新生儿因素（性别、胎龄、出生体重z评分、分娩方式、脐带血糖浓度）后，吸烟母亲所产新生儿的IGF-I浓度显著低于非吸烟母亲所产新生儿（均值：6.7 vs 8.4 nmol/L，校正后p=0.006），且胰岛素原-胰岛素比值略高于后者（0.94 vs 0.72，校正后p=0.06）。吸烟与非吸烟母亲所产新生儿的脐带血浆胰岛素、胰岛素原、IGF-II、瘦素、脂联素浓度以及葡萄糖-胰岛素比值均无显著差异。

研究结论
母体吸烟与胎儿IGF-I水平降低存在关联，且胎儿β细胞功能存在临界性下降。需开展更大规模的队列研究以验证后一发现。本初步研究结果提出假说：此类生命早期代谢改变可能参与了母体吸烟对子代未来罹患代谢综合征相关疾病的风险影响。