Eskandarifar Alireza, Roshani Daem, Tabarkhun Ali, Ataee Edram
Department of Pediatric, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
Iran J Kidney Dis. 2021 Mar;1(2):116-120.
Detection of nephrolithiasis is readily possible in infants with the advent of new imaging technology. Vitamin D is routinely given to newborn infants shortly after birth during infancy. Vitamin D is known to increase urinary calcium excretion which may be responsible for the increased incidence of nephrolithiasis during infancy. To test this hypothesis we studied the serum level of vitamin D and renal handling of calcium in infants with nephrolithiasis .
In this prospective case-controlled study, we measured serum levels of vitamin D and calcium accompanied by urinary calcium level in infants between 1 to 12 months with nephrolithiasis who fed with breast milk and vitamin D supplement and compared these parameters with healthy infants without nephrolithiasis after matching for sex and postnatal age as the control group. All infants with nephrolithiasis were evaluated for metabolic disorders and other risk factors and positive cases were excluded from the study.
Fifty infants between 1 to 12 months with mean postnatal age 6.96 ± 2.29 months with nephrolithiasis and 50 control infants with mean postnatal age 6.94 ± 2.55 months were enrolled in the study. Mean serum level of vitamin D in the case and control groups was 41.49 ± 11.69 and 35.67 ± 6.76 ng/mL, respectively. Mean serum level of calcium in case group was 9.63 ± 0.32 vs. 8.59 ± 1.21 mg/dL in the control group. Mean urinary calcium- creatinine ratio (Ca/Cr) in the study and control groups was 0.15 ± 0.16 and 0.08 ± 0.02, respectively, Differences were statistically significant in all three variables (P < .05).
Routine consumption of vitamin D increases urinary level of calcium and in presence of other predisposing factors could accelerate the genesis of nephrolithiasis in infants.
随着新成像技术的出现，婴儿肾结石的检测变得容易实现。婴儿出生后不久通常会常规补充维生素D。已知维生素D会增加尿钙排泄，这可能是婴儿期肾结石发病率增加的原因。为了验证这一假设，我们研究了肾结石婴儿的维生素D血清水平和肾脏对钙的处理情况。
在这项前瞻性病例对照研究中，我们测量了1至12个月患有肾结石且以母乳喂养并补充维生素D的婴儿的维生素D和钙血清水平以及尿钙水平，并将这些参数与匹配了性别和出生后年龄的无肾结石健康婴儿作为对照组进行比较。所有患有肾结石的婴儿都进行了代谢紊乱和其他危险因素的评估，阳性病例被排除在研究之外。
本研究纳入了50名1至12个月、平均出生后年龄为6.96±2.29个月的肾结石婴儿和50名平均出生后年龄为6.94±2.55个月的对照婴儿。病例组和对照组的维生素D平均血清水平分别为41.49±11.69和35.67±6.76 ng/mL。病例组的钙平均血清水平为9.63±0.32 mg/dL，而对照组为8.59±1.21 mg/dL。研究组和对照组的尿钙肌酐比值（Ca/Cr）分别为0.15±0.16和0.08±0.02，所有三个变量的差异均具有统计学意义（P<.05）。
常规补充维生素D会增加尿钙水平，在存在其他易感因素的情况下，可能会加速婴儿肾结石的发生。
