Western Style Diets Linked to Kidney Dysfunction

A Western diet is associated with a greater likelihood of the development of microalbuminuria (excretion of small amounts of albumin to the urine) and rapid decrease in kidney function, according to a study published in the February issue of the American Journal of Kidney Diseases. The study also showed that diets similar to the Dietary Approach to Stop Hypertension (DASH) diet may be protective against rapid decline of estimated glomerular filtration rate (eGFR).Previous research has linked dietary patterns to cardiovascular disease and other chronic diseases, but little is known about the connection between diet and the propensity for the development of microalbuminuria or kidney function decrease.

The study compared 3 diets: a Western diet high in red and processed meats, saturated fats, and sweets; a prudent diet high in fruits, vegetables, legumes, fish, poultry, and whole grains; and a DASH-style dietary pattern.

Julie Lin, MD, MPH, from Brigham and Women’s Hospital, Harvard Medical School, in Boston, Massachusetts, and colleagues conducted a subgroup analysis from the Nurses’ Health Study, which is a prospective observational cohort study. They selected female participants who had provided dietary pattern data on food frequency questionnaires returned in 1984, 1986, 1990, 1994, and 1998, as well as albumin-to-creatinine ratios from 2000 (n = 3121). For 3071 of the participants, change in eGFR occurred between 1989 and 2000. Outcomes of the study included microalbuminuria (albumin-to-creatinine ratio, 25 – 354 µg/mg) in 2000 and change in eGFR between 1989 and 2000.

When the researchers compared the highest quartile of Western pattern score vs the lowest quartile, they found that high scores correlated directly with microalbuminuria (odds ratio [OR], 2.17; 95% confidence interval [CI], 1.18 – 3.66; P = 0.01) and rapid eGFR decline of at least 3 mL/minute/1.73 m²/year (OR, 1.77; 95% CI, 1.03 – 3.03). When they did a similar comparison among DASH scores, they found that women in the top quartile had a decreased risk for rapid eGFR decline (OR, 0.55; 95% CI, 0.38 – 0.80). There was no association with microalbuminuria.

These associations did not vary by diabetes status. Differences in the prudent dietary pattern were not associated with microalbuminuria or eGFR decline.

The researchers focused on dietary patterns rather than individual ingredients because they believed the additive or interactive influence of foods could be more readily observed. They also thought it could translate better into dietary advice. Finally, they suspected that focusing on diet would produce a larger contrast than a focus on individual nutrients or foods because of the potential of collinearity.

Study limitations included a cohort population of primarily older white women. It could be made more generalizable by validation in nonwhites and men, the study authors write.

The study authors have disclosed no relevant financial relationships.

Am J Kidney Dis. 2011;57:245-254

Source:  http://www.medscape.com/viewarticle/737174?sssdmh=dm1.665339&src=nldne