Objective: To investigate vitamin D level at birth and possible influencing factors in preterm infants.
Methods: A total of 600 preterm infants were enrolled, and venous blood samples were collected within 24 hours after birth to measure the serum level of 25-hydroxyvitamin D [25(OH)D]. The effect of sex, birth weight, birth season, gestational age, mother's age, body mass index (BMI) in early pregnancy, delivery mode, and complications during pregnancy on serum 25(OH)D level was analyzed.
Results: The rates of vitamin D deficiency, insufficiency, and sufficiency were 42.0%, 38.7%, and 19.3% respectively. The preterm infants born in summer and autumn had a significantly higher serum 25(OH)D level than those born in winter (P<0.05) and a significantly lower incidence rate of vitamin D deficiency than those born in spring and winter (P<0.003). Compared with those whose mothers were aged <30 years, the infants whose mothers were aged ≥30 years had a significantly higher serum 25(OH)D level (P<0.05) and a significantly lower incidence rate of vitamin D deficiency (P<0.017). Compared with those whose mothers were overweight or had normal body weight, the infants whose mothers were obese had a significantly lower serum 25(OH)D level (P<0.05) and a significantly higher incidence rate of vitamin D deficiency (P<0.006). Compared with those whose mothers had no preeclampsia, the infants whose mothers had preeclampsia during pregnancy had a significantly lower serum 25(OH)D level (P<0.05) and a significantly higher incidence rate of vitamin D deficiency (P<0.017). The multivariate analysis showed that birth in winter and spring, mother's age <30 years, and early-pregnancy BMI ≥28 kg/m2 were risk factors for vitamin D deficiency (P<0.05).
Conclusions: There is a high prevalence of vitamin D deficiency in preterm infants. Vitamin D supplementation should be given to the preterm infants with high-risk factors for vitamin D deficiency.
目的: 分析早产儿出生时维生素D水平及其可能影响因素。
方法: 采集600例早产儿出生24 h内静脉血，检测血清25-羟基维生素D[25（OH）D]水平，并分析早产儿性别、出生体重、出生季节、胎龄，以及母亲的年龄、职业、早孕期体重指数（BMI）、分娩方式及妊娠期并发症等对血清25（OH）D水平的影响。
结果: 早产儿维生素D缺乏、不足、充足的比例分别为42.0%、38.7%和19.3%。夏、秋季出生的早产儿血清25（OH）D水平显著高于冬季（P < 0.05），维生素D缺乏的发生率显著低于春、冬季（P < 0.003）。与母亲年龄≥ 30岁者比较，年龄 < 30岁母亲所生早产儿血清25（OH）D水平显著降低（P < 0.05），维生素D缺乏的发生率显著增高（P < 0.017）。与母亲肥胖者比较，超重或体重正常母亲所生早产儿血清25（OH）D水平显著增高（P < 0.05），维生素D缺乏的发生率显著降低（P < 0.006）。母亲妊娠合并子癎前期者，其早产儿血清25（OH）D水平显著低于无子癎前期者（P < 0.05），维生素D缺乏的发生率显著高于无子癎前期者（P < 0.017）。多因素分析结果显示，冬春季出生、母亲年龄 < 30岁及早孕期BMI ≥ 28 kg/m2为早产儿维生素D缺乏的危险因素（P < 0.05）。
结论: 早产儿维生素D缺乏发生率较高，有维生素D缺乏高危因素的早产儿生后需尽早补充维生素D。