The association between a Mediterranean-style diet and kidney function in the Northern Manhattan Study cohort.

BACKGROUND AND OBJECTIVES: Various dietary strategies have been investigated to slow kidney function decline. However, it is unknown whether a Mediterranean diet, which has been associated with improved cardiovascular risk, is associated with change in kidney function. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This study used the Northern Manhattan Study, a prospective, multiethnic, observational cohort of participants who were stroke free at baseline. Data were collected between 1993 and 2008. Serum creatinine measurements were taken a mean 6.9 years apart. A baseline dietary questionnaire was extrapolated into a previously used 9-point scoring system (MeDi). The primary outcome was incident eGFR<60 ml/min per 1.73 m(2)using the Modification of Diet in Renal Disease formula. A secondary outcome was the upper quartile of annualized eGFR decline (≥ 2.5 ml/min per 1.73 m(2) per year). Conditional logistic regression models adjusted for demographics and baseline vascular risk factors.
RESULTS: Mean baseline age was 64 years, with 59% women and 65% Hispanics (N=900); mean baseline eGFR was 83.1 ml/min per 1.73 m(2). Incident eGFR<60 ml/min per 1.73 m(2) developed in 14% . In adjusted models, every 1-point increase in the MeDi score, indicating increasing adherence to a Mediterranean diet, was associated with decreased odds of incident eGFR<60 ml/min per 1.73 m(2) (odds ratio, 0.83; 95% confidence interval, 0.71 to 0.96) and decreased odds of being in the upper quartile of eGFR decline (odds ratio, 0.88; 95% confidence interval, 0.79 to 0.98).
CONCLUSIONS: A Mediterranean diet was associated with a reduced incidence of eGFR<60 ml/min per 1.73 m(2) and upper quartile of eGFR decline in a multiethnic cohort.