Sorof J M, Forman A, Cole N, Jemerin J M, Morris R C
Department of Pediatrics, University of California-San Francisco, USA.
J Pediatr. 1997 Jul;131(1 Pt 1):87-94. doi: 10.1016/s0022-3476(97)70129-x.
Our study objectives were as follows: (1) to determine whether urinary excretion of potassium is lower in black than in white children, (2) to determine whether cardiovascular reactivity (CVR) varies inversely with dietary intake of potassium, and (3) to confirm that CVR is greater in black than in white children, and in children with a family history of hypertension than in those without such a history.
Baseline measurements included 24-hour urinary sodium, potassium, and creatinine levels and food intake (by questionnaire). Resting and stress blood pressure were measured during blood sampling, cold water foot immersion, and a video game before and after 1 week each of supplementation with potassium citrate, 1.5 mmol/kg per day, and placebo administered in random order.
Thirty-nine children aged 7 to 15 years were studied. White subjects had higher baseline excretion of potassium than black subjects (p < 0.001) and higher vegetable intake (p < 0.01), which were positively correlated (r = 0.53, p < 0.001). At baseline, the 24-hour urinary potassium/creatinine ratio varied inversely with diastolic CVR to the video game stressor in white children (r = -0.55, p = 0.02). Cardiovascular reactivity was not attenuated measurably by potassium supplementation compared with placebo. The CVR was greater in children with a family history of hypertension than in those without, but was not greater in black children than in white children.
The urinary potassium/creatinine ratio is higher in white than black children because their intake of vegetables is greater; dietary potassium intake may modulate CVR, particularly in white children with a family history of hypertension, but may need to be supplemented for more than 1 week to demonstrate attenuation of CVR; and a family history of hypertension may be a stronger predictor of enhanced CVR than is race.
我们的研究目的如下：（1）确定黑人儿童的尿钾排泄量是否低于白人儿童；（2）确定心血管反应性（CVR）是否与钾的饮食摄入量呈负相关；（3）证实黑人儿童的CVR高于白人儿童，且有高血压家族史的儿童的CVR高于无此家族史的儿童。
基线测量包括24小时尿钠、钾和肌酐水平以及食物摄入量（通过问卷调查）。在随机顺序给予每天1.5 mmol/kg枸橼酸钾和安慰剂各1周前后，于采血、冷水浸足和玩电子游戏期间测量静息血压和应激血压。
研究了39名7至15岁的儿童。白人受试者的钾基线排泄量高于黑人受试者（p<0.001），蔬菜摄入量也更高（p<0.01），二者呈正相关（r = 0.53，p<0.001）。基线时，白人儿童24小时尿钾/肌酐比值与电子游戏应激源引起的舒张期CVR呈负相关（r = -0.55，p = 0.02）。与安慰剂相比补充钾后心血管反应性没有明显减弱。有高血压家族史的儿童的CVR高于无家族史的儿童，但黑人儿童的CVR并不高于白人儿童。
白人儿童的尿钾/肌酐比值高于黑人儿童，因为他们的蔬菜摄入量更大；饮食中的钾摄入量可能调节CVR，特别是在有高血压家族史的白人儿童中，但可能需要补充超过1周才能显示CVR减弱；高血压家族史可能比种族更能预测CVR增强。
