• The UK Biobank enrolled approximately 500,000 men and women ages 40 to 69 years between 2006 and 2010 in a study designed to improve understanding of incidence, prevention, and treatment of a number of diseases. It contained detailed information regarding self-reported “usual” food and drink intake among participants and, as such, represented a unique dataset from which to perform a population-based assessment of the impact of dietary habits on risk of nephrolithiasis. Of the 439,072 participants included in the analysis, 2327 developed an incident symptomatic stone during the follow-up period at a mean of 6.1 years. Each additional 200-mL increase in fluid intake was associated with a 13% decreased risk of stones, and each 100-g increase in fruit (HR, 0.88) and 10 g of fiber (HR, 0.82,) were similarly protective. In contrast, meat (17% per each additional 50 g per week) and salt intake (33% increase for those who “always” add salt to food) were significantly associated with stones.

• These data inform the extent to which population-wide counseling regarding dietary modifications could impact stone risk.

– Joshua Cohn, MD

Abstract
This abstract is available on the publisher’s site.

BACKGROUND
Fluid intake and diet are thought to influence kidney stone risk. However, prospective studies have been limited to small samples sizes and/or restricted measures.

OBJECTIVE
To investigate whether fluid intake and dietary factors are associated with the risk of developing a first kidney stone.

DESIGN, SETTING, AND PARTICIPANTS
Participants were selected from UK Biobank, a population-based prospective cohort study.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS
Cox proportional hazards models were used to investigate the association between fluid intake and dietary factors and the risk of a first incident kidney stone, ascertained from hospital inpatient records.

RESULTS AND LIMITATIONS
After exclusion, 439 072 participants were available for the analysis, of whom 2057 had hospital admission with an incident kidney stone over a mean of 6.1 yr of follow-up. For every additional drink (200 ml) consumed per day of total fluid, the risk of kidney stones declined by 13% (hazard ratio [HR] = 0.87, 95% confidence interval [CI] 0.85-0.89). Similar patterns of associations were observed for tea, coffee, and alcohol, although no association was observed for water intake. Fruit and fibre intake was also associated with a lower risk (HR per 100 g increase of fruits per day = 0.88, 95% CI 0.83-0.93, and HR per 10 g fibre per day = 0.82, 95% CI 0.77-0.87), whereas meat and salt intake was associated with a higher risk (HR per 50 g increase in meat per week = 1.17, 95% CI 1.05-1.29, and HR for always vs never/rarely added salt to food = 1.33, 95% CI 1.12-1.58). Vegetable, fish, and cheese intake was not associated with kidney stone risk.

CONCLUSIONS
The finding that high intake of total fluid, fruit, and fibre was associated with a lower risk of hospitalisation for a first kidney stone suggests that modifiable dietary factors could be targeted to prevent kidney stone development.

PATIENT SUMMARY
We found that higher intake of total fluid, specifically tea, coffee, and alcohol (but not water), and consumption of fruit and foods high in fibre are linked with a reduced likelihood of developing kidney stones.

Journal Reference

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