Schmidt Ida M, Chellakooty Marla, Boisen Kirsten A, Damgaard Ida N, Mau Kai Claudia, Olgaard Klaus, Main Katharina M
University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark.
Kidney Int. 2005 Aug;68(2):731-40. doi: 10.1111/j.1523-1755.2005.00451.x.
Low birth weight is an important risk factor for hypertension and unfavorable prognoses of a number of renal diseases. It is also associated with reduced kidney size and nephron number. A differentiation between the effects of low birth weight versus being born premature or small for gestational age has, however, not been addressed.
The influence of weight for gestational age (percentage deviation from expected mean), gestational age, birth weight, and early diet on kidney growth was studied in 178 children born pre- or postmature and/or small or large for gestational age, comparing them to 717 mature children, birth weight appropriate for gestational age. Kidney size was determined by bilateral ultrasonography measuring length, width and depth, using the equation of an ellipsoid for volume calculation. The examinations were performed at 0, 3, and 18 months of age together with measurements of body weight, height, and skinfold thickness.
Weight for gestational age had a significant, positive effect on combined kidney volume at all three ages (0 months, P < 0.001; 3 months, P < 0.001; and 18 months, P < 0.001). A slight catch-up growth in kidney size was seen in the most growth-retarded infants (<10th percentile) between 0 and 18 months of age (mean Deltaz score(0-18 mo)=+0.22 SD) (P= 0.037). Premature children had smaller kidneys compared to mature at all ages (0 months, P= 0.001; 3 months, P= 0.007; and 18 months, P= 0.042), without any significant catch-up with age. Relative kidney volume was inversely correlated with weight for gestational age at birth (P= 0.007) but positively at 18 months (P= 0.008). Relative kidney growth 0 to 18 months was positively correlated to weight for gestational age (P= 0.013). Low birth weight was associated with impaired relative kidney growth in response to formula feeding.
Being small for gestational age is associated with small kidneys at birth and impaired kidney growth in early childhood. The present data suggest that intrauterine growth has a regulatory influence on nephron formation and renal function in humans reaching beyond the neonatal period.
低出生体重是高血压及多种肾脏疾病不良预后的重要危险因素。它还与肾脏体积减小和肾单位数量减少有关。然而，低出生体重与早产或小于胎龄儿的影响之间的差异尚未得到研究。
研究了178例早产或足月产及小于或大于胎龄儿的胎龄体重（与预期均值的百分比偏差）、胎龄、出生体重和早期饮食对肾脏生长的影响，并将其与717例出生体重适合胎龄的足月儿进行比较。通过双侧超声测量肾脏的长度、宽度和深度，使用椭球体公式计算体积来确定肾脏大小。在0、3和18月龄时进行检查，同时测量体重、身高和皮褶厚度。
胎龄体重在所有三个年龄段（0个月，P<0.001；3个月，P<0.001；18个月，P<0.001）对双肾总体积均有显著的正向影响。在0至18月龄时，生长最迟缓的婴儿（<第10百分位数）出现了轻微的肾脏大小追赶生长（平均Delta z评分（0 - 18个月）= +0.22标准差）（P = 0.037）。与足月儿相比，早产儿在各年龄段的肾脏均较小（0个月，P = 0.001；3个月，P = 0.007；18个月，P = 0.042），且未随年龄出现显著的追赶生长。出生时相对肾脏体积与胎龄体重呈负相关（P = 0.007），但在18个月时呈正相关（P = 0.008）。0至18个月的相对肾脏生长与胎龄体重呈正相关（P = 0.013）。低出生体重与配方奶喂养时相对肾脏生长受损有关。
小于胎龄儿出生时肾脏较小，且幼儿期肾脏生长受损。目前的数据表明，宫内生长对人类肾单位形成和肾功能具有调节作用，这种作用超出了新生儿期。
