Taylor Eric N, Curhan Gary C
Channing Laboratory, Third Floor, Brigham and Women's Hospital, Boston, MA 02115, USA.
J Am Soc Nephrol. 2007 Jul;18(7):2198-204. doi: 10.1681/ASN.2007020219. Epub 2007 May 30.
Most kidney stones consist of calcium oxalate, and higher urinary oxalate increases the risk for calcium oxalate nephrolithiasis. However, the relation between dietary oxalate and stone risk is unclear. This study prospectively examined the relation between oxalate intake and incident nephrolithiasis in the Health Professionals Follow-up Study (n = 45,985 men), the Nurses' Health Study I (n = 92,872 older women), and the Nurses' Health Study II (n = 101,824 younger women). Food frequency questionnaires were used to assess oxalate intake every 4 yr. Cox proportional hazards regression was used to adjust for age, body mass index, thiazide use, and dietary factors. A total of 4605 incident kidney stones were documented over a combined 44 yr of follow-up. Mean oxalate intakes were 214 mg/d in men, 185 mg/d in older women, and 183 mg/d in younger women and were similar in stone formers and non-stone formers. Spinach accounted for >40% of oxalate intake. For participants in the highest compared with lowest quintile of dietary oxalate, the relative risks for stones were 1.22 (95% confidence interval [CI] 1.03 to 1.45; P = 0.01 for trend) for men and 1.21 (95% CI 1.01 to 1.44; P = 0.05 for trend) for older women. Risk was higher in men with lower dietary calcium (P = 0.08 for interaction). The relative risks for participants who ate eight or more servings of spinach per month compared with fewer than 1 serving per month were 1.30 (95% CI 1.08 to 1.58) for men and 1.34 (95% CI 1.10 to 1.64) for older women. Oxalate intake and spinach were not associated with risk in younger women. These data do not implicate dietary oxalate as a major risk factor for nephrolithiasis.
大多数肾结石由草酸钙组成，尿草酸水平升高会增加草酸钙肾结石的风险。然而，饮食中草酸与结石风险之间的关系尚不清楚。本研究在健康专业人员随访研究（n = 45985名男性）、护士健康研究I（n = 92872名老年女性）和护士健康研究II（n = 101824名年轻女性）中前瞻性地研究了草酸摄入量与新发肾结石之间的关系。每4年使用食物频率问卷评估草酸摄入量。采用Cox比例风险回归对年龄、体重指数、噻嗪类药物使用情况和饮食因素进行校正。在总计44年的随访期间，共记录到4605例新发肾结石病例。男性的平均草酸摄入量为214 mg/天，老年女性为185 mg/天，年轻女性为183 mg/天，结石患者和非结石患者的草酸摄入量相似。菠菜占草酸摄入量的40%以上。与饮食草酸摄入量最低的五分位数参与者相比，最高五分位数参与者的结石相对风险在男性中为1.22（95%置信区间[CI] 1.03至1.45；趋势P = 0.01），在老年女性中为1.21（95%CI 1.01至1.44；趋势P = 0.05）。饮食钙含量较低的男性风险更高（交互作用P = 0.08）。与每月食用菠菜少于1份的参与者相比，每月食用8份或更多份菠菜的参与者的相对风险在男性中为1.30（95%CI 1.08至1.58），在老年女性中为1.34（95%CI 1.10至1.64）。草酸摄入量和菠菜与年轻女性的风险无关。这些数据并未表明饮食草酸是肾结石的主要危险因素。
