Population-based dietary risks for kidney stones Implications for dietary counseling and prevention

In the context of the increasing incidence of kidney stones, we aimed to assess the percentage of the population who are eating an at-risk diet for kidney stones and to understand the baseline diet for future counseling.

The 2015 Canadian Community Health Survey, a national, cross-sectional instrument administered by Statistics Canada and Health Canada, was queried. Intake of relevant nutrients was compared to dietary risk factors for kidney stone formation. Factors associated with nutrient intake were analyzed in a multivariable regression.

Data for 14 275 participants was included, of whom 24% consumed >2.5 L of fluid per day and 9.4% consumed 1000-1200 mg of dietary calcium; 53.9% consumed too much sodium but 61% of the population had the recommended protein intake. Ninety-nine percent (99%) of the population had at least one dietary risk factor for kidney stone formation, while 92% had two or more risk factors. Fluid, sodium, calcium, and protein intake increased significantly with education level, income, and if employed (p<0.05 for all); however, fluid, protein, and sodium intake were lower in patients with hypertension and heart disease (p<0.05 for all).

While only a subset of the population will develop stones, this study shows that 99% of the population has a diet that elevates the risk of stone disease. As the incidence of kidney stones increases, population-based dietary interventions should be considered. Furthermore, clinicians may use these data to understand the average diet as a starting point for questioning and counseling patients.