Adherence to the Mediterranean Dietary Pattern and Incidence of Nephrolithiasis in the Seguimiento Universidad de Navarra Follow-up (SUN) Cohort.

BACKGROUND

Diet plays an important role in the pathogenesis of nephrolithiasis. Limited data are available to investigate the association between a Mediterranean dietary pattern and risk for nephrolithiasis.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS: 16,094 men and women without a history of nephrolithiasis who participated in the Seguimiento Universidad de Navarra Follow-up (SUN) Project.

PREDICTORS

A validated 136-item food frequency questionnaire was used to assess baseline adherence to a Mediterranean dietary pattern that is high in fruits, vegetables, nuts, fish, and legumes, but moderate in alcohol and low in meats, saturated fats, and sugars. A Mediterranean dietary pattern score was calculated and categorized into 3 groups (0-3, 4-6, and 7-9 points). Additional factors included in statistical models were sex, age, body mass index, smoking, physical activity, time spent watching television, following a medical nutritional therapy, water and energy intake, calcium and vitamin D supplementation, and history of hypertension or diabetes.

OUTCOMES

Incidence of nephrolithiasis. Participants were classified as having incident nephrolithiasis if they reported a physician-made diagnosis of nephrolithiasis during follow-up.

RESULTS

After a mean follow-up of 9.6 years, 735 new cases of nephrolithiasis were identified. The multivariable HRs of nephrolithiasis for the 2 highest categories of adherence to the Mediterranean dietary pattern, using the lowest category as the reference, were 0.93 (95% CI, 0.79-1.09) and 0.64 (95% CI, 0.48-0.87); P for trend=0.01. The risk for nephrolithiasis was lower with greater consumption of dairy products and vegetables and greater with higher monounsaturated fatty acid to saturated fatty acid ratio.

LIMITATIONS

No information for kidney stone composition.

CONCLUSIONS

Greater adherence to a Mediterranean dietary pattern was associated with reduced risk for incident nephrolithiasis. Additional longitudinal studies are needed.