Abstract P417: A Cumulative Score Approach to Evaluating the Impact of Five Modifiable Lifestyle Factors on Kidney Function

Abstract

Background: Data from the Gubbio population study were used to investigate the impact of a cumulative score combining physical activity, intake of alcohol, sodium, potassium and protein on the decline of kidney function. Methods: The Gubbio Study is a longitudinal study on the population of Gubbio, a town in central Italy; it started in the year 1983, and addressed the resident population aged 5 +. Three exams were performed: Exam 1 (baseline) Exam 2 (6-year follow-up) and Exam 3 (20-year follow-up); this analysis is on the 3,039 adult individuals (Age 18+ at baseline) who participated in Exam 2 (1989-92) and Exam 3 (2001-07). Kidney function was estimated as glomerular filtration rate (eGFR) with the CKD-Epi equation (mL/min x 1.73 m 2 ). Habitual physical activity and alcohol intake were assessed by standard questionnaires. Dietary intake of protein, sodium and potassium were measured by urinary markers. Each factor received score 0 for the tertile associated with greater eGFR decline, score 1 for the tertile associated with intermediate decline and score 2 for the tertile associated with greater decline. A cumulative score (CS) was then calculated for each individual and used as main independent variable. Results: After correction to avoid low-n bias, the CS ranged from 1 (low risk for all factors) to 9 (high risk for all factors). The mean was 5+/-2, with skewness = 0.016. Multiple linear regression showed a relation with the annualized decline in eGFR (slope = - 0,027, 95% CI = - 0.039/ - 0.014, p < 0.001). Incidence of low eGFR was higher in the groups with higher CS, ranging from 2% in the group with CS = 1 to 12.9% in the group with CS = 9. Multivariate logistic regression analysis confirmed the correlation (p < 0.001). Conclusion: These data indicate a significant independent association between a score comprising five modifiable lifestyle factors and the long-term decline of kidney function, providing a tool for the quantification of its impact on the long-term incidence of low eGFR.