Association of dietary protein intake and microalbuminuria in healthy adults: Third National Health and Nutrition Examination Survey.
BACKGROUND
The relationship between dietary protein intake (DPI) and microalbuminuria (MA) is unclear. We investigated whether DPI was associated with urinary albumin level in a population sample of persons with normal kidney function.


METHODS
We addressed this question in adults aged 20 to 80 years from the Third National Health and Nutrition Examination Survey (n = 12,422). DPI was assessed from a 24-hour dietary recall and quantified as percentage of total energy intake. MA is defined as urinary albumin-creatinine ratio 30 mg/g (3 mg/mmol) or greater.


RESULTS
In multivariable logistic regression models adjusted for sociodemographic characteristics and coronary heart disease risk factors, DPI was not associated with MA in normotensive or nondiabetic persons. In crude models, odds ratios (ORs) for MA were 1.9 (95% confidence interval, 1.2 to 3.0) in persons with hypertension (n = 3,433) and 2.4 (95% confidence interval, 1.1 to 5.2) in those with diabetes (n = 1,165) in the highest (>19%) versus lowest (<11.7%) quintile of DPI. However, in models adjusted for the concurrent prevalence of diabetes or hypertension, this association attenuated to nonsignificance. Persons in the highest quintile of DPI who had both hypertension and diabetes (n = 634) had a significantly elevated OR for MA (3.3; 95% confidence interval, 1.4 to 7.8) compared with those in the lowest quintile.


CONCLUSIONS
DPI is not associated with MA in healthy persons or those with isolated hypertension or diabetes. However, in persons with both conditions, high DPI is associated with increased prevalence of MA. These findings suggest the need for further research on weight-loss strategies for high-risk persons.
Wrone
Elizabeth M
EM
Stanford Center for Research in Disease Prevention, Stanford University School of Medicine, Stanford, CA, USA.
Carnethon
Mercedes R
MR
Palaniappan
Latha
L
Fortmann
Stephen P
SP
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000418:Albumins / Q000378:metabolism; D000419:Albuminuria / Q000453:epidemiology*; D003404:Creatinine / Q000652:urine; D003906:Developing Countries / Q000706:statistics & numerical data; D003920:Diabetes Mellitus / Q000453:epidemiology; D004044:Dietary Proteins / Q000378:metabolism*; D005006:Ethnicity / Q000706:statistics & numerical data; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D016015:Logistic Models; D008875:Middle Aged; D015999:Multivariate Analysis; D009749:Nutrition Surveys; D044469:Racial Groups; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology
D000418:Albumins; D004044:Dietary Proteins; D003404:Creatinine