Relationship between dietary intake and microalbuminuria: Findings from the Takahata study

Background: Although several studies have investigated the relationship between dietary nutrient intake and microalbuminuria, no study of an Asian population has been reported. The present study investigates the relationship between dietary intake and microalbuminuria in a general Japanese population. Methods: We analyzed 675 men and 924 women who did not have diabetes. Participants who had a urinary albumin-to-creatinine ratio (UACR) ≥300 mg/g, who did not complete a questionnaire regarding food frequency and who did not provide complete urine measurements were excluded. Nutrient intake was assessed by validated food frequency questionnaire. Microalbuminuria was defined as UACR ≥30 mg/g. The relationship between dietary nutrient intake and microalbuminuria was examined using a multiple logistic regression model adjusted for age, total energy intake, body mass index, smoking status, systolic blood pressure and use of antihypertensive medication. Results: No significant association was observed among the men. The multiple adjusted odds ratios (95% confidence interval) of having microalbuminuria per 1 standard deviation increase in total protein (%kcal), animal protein (%kcal), animal protein (g/day), animal fat, niacin, carbohydrate and β-cryptoxanthin among the women were 1.33 (1.07-1.66), 1.35 (1.09-1.66), 1.42 (1.08-1.88), 1.29 (1.05-1.59), 1.28 (1.04-1.57), 0.73 (0.58-0.92) and 0.76 (0.59-0.996), respectively. The multiple adjusted odds ratio (95% confidence interval) of having microalbuminuria in the highest quintile of n-3 polyunsaturated fatty acids compared with the lowest was 2.16 (1.03-4.54). Conclusion: Less animal protein and more β-cryptoxanthin in the diet might help to prevent microalbuminuria. Prospective studies including controlled trials are required to confirm this conclusion.