Dietary Factors and the Risk of Incident Kidney Stones in Men

Abstract

Abstract. Diet plays an important role in the pathogenesis of kidney stones. Because the metabolism of many dietary factors, such as calcium, may change with age, the relation between diet and kidney stones may be different in older adults. Uncertainty also remains about the association between many dietary factors, such as vitamin C, magnesium, and animal protein, and the risk of kidney stone formation. To examine the association between dietary factors and the risk of incident, symptomatic kidney stones in men and to determine whether these associations vary with age, a prospective cohort study was conducted of 45,619 men without a history of nephrolithiasis. Self-administered food frequency questionnaires were used to assess diet every 4 yr. A total of 1473 incident symptomatic kidney stones were documented during 477,700 person-years of follow-up. For men aged Ͻ60 yr, the multivariate relative risk (RR) for stone formation in the highest quintile of dietary calcium as compared with the lowest quintile was 0.69 (95% confidence interval [CI], 0.56 to 0.87; P ϭ 0.01 for trend). By contrast, there was no association between dietary calcium and stone formation in men aged 60 yr or older. The multivariate RR for men who consumed 1000 mg or greater of vitamin C per day compared with those who consumed less than the recommended dietary allowance of 90 mg/d was 1.41 (95% CI, 1.11 to 1.80; P ϭ 0.01 for trend). Other dietary factors showed the following multivariate RR among men in the highest quintile of intake compared with those in the lowest: magnesium, 0.71 (95% CI, 0.56 to 0.89; P ϭ 0.01 for trend); potassium, 0.54 (95% CI, 0.42 to 0.68; P Ͻ 0.001 for trend); and fluid, 0.71 (95% CI, 0.59 to 0.85; P Ͻ 0.001 for trend). Animal protein was associated with risk only in men with a body mass index Ͻ25 kg/m 2 (RR, 1.38; 95% CI, 1.05 to 1.81; P ϭ 0.03 for trend). Sodium, phosphorus, sucrose, phytate, vitamin B 6 , vitamin D, and supplemental calcium were not independently associated with risk. In conclusion, the association between calcium intake and kidney stone formation varies with age. Magnesium intake decreases and total vitamin C intake seems to increase the risk of symptomatic nephrolithiasis. Because age and body size affect the relation between diet and kidney stones, dietary recommendations for stone prevention should be tailored to the individual patient.Diet plays an important role in the pathogenesis of kidney stones (1), but little is known about the effect of aging on the association between specific dietary factors and nephrolithiasis. In the past, prospective studies that evaluated dietary influences on kidney stone formation included only small numbers of older participants. The first observational studies to demonstrate an inverse association between dietary calcium and incident kidney stones analyzed stone formers who as a group were predominately younger than 60 yr (2,3). The mean age of subjects in the controlled, randomized trial that supported the results of these studies was 45 yr (4).The relati...

Dietary and Lifestyle Factors and Medical Conditions Associated with Urinary Citrate Excretion

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Calcium and vitamin D supplements administration in patients with nephrolithiasis; an observational prospective study

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Use of the probability of stone formation (PSF) score to assess stone forming risk and treatment response in a cohort of Brazilian stone formers

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