Dietary Risk Factors for Pediatric Kidney Stones: A Case-Control Study.

PURPOSE

Data are scarce regarding dietary risk factors for pediatric nephrolithiasis. Our objective was to perform a case-control study (nonmatched) of the association of dietary nutrients with pediatric urolithiasis.

MATERIALS AND METHODS

We obtained dietary information from pediatric urolithiasis patients (from stone clinic in 2013-2016) and healthy controls (well-child visit at primary care in 2011-2012). Survey results were converted to standard nutrient intakes. Children younger than 5 years of age and those with extreme calorie intake values (<500 or >5,000 kcal/day) were excluded. The association of individual nutrients with urolithiasis was assessed by bivariate analysis results and machine-learning methods. A multivariable logistic regression model was fitted using urolithiasis as the outcome.

RESULTS

We included 285 patients (57 stones/228 controls). Mean±SD age was 8.9±3.6 years (range 5-20). Of the patients 47% were male. After adjusting for age, sex, body mass index (obese/overweight/normal), calorie intake and oxalate, urolithiasis was associated with higher dietary sodium (OR=2.43 [95% CI=1.40-4.84] per quintile increase, p=0.004), calcium (OR=1.73 [95% CI=1.07-3.00] per quintile increase, p=0.034) and beta carotene (OR=2.01 [95% CI=1.06-4.18] per quintile increase, p=0.042), and lower potassium (OR=0.31 [95% CI=0.13-0.63] per quintile increase, p=0.003). Sensitivity analysis was performed by removing oxalate from the model and limiting the sample to patients aged 5-13 years, with similar results.

CONCLUSIONS

In our cohort, higher dietary intake of calcium, sodium and beta carotene, and lower potassium intake were associated with pediatric urolithiasis. This is the first study using a detailed dietary survey to identify dietary risk factors for pediatric urolithiasis. Further research is warranted to delineate the mechanisms and to generate a lower risk diet profile for pediatric urolithiasis.