High prevalence of microalbuminuria in the overweight and obese population: data from a UK population screening programme.

BACKGROUND

Microalbuminuria (MA) is associated with increased risk of cardiovascular and possibly chronic kidney disease (CKD). Obesity has been linked to MA, though the prevalence of MA in overweight groups is not well documented. This population study with an overrepresentation of individuals with BMI >25 (calculated as kg/m2) investigates the prevalence of MA in different BMI categories, and the relationship between MA and BMI.

METHODS

Data from two cross-sectional epidemiological studies in the City of Sheffield were combined to produce a cohort of non-diabetic, non-CKD subjects over the age of 18. The first study, Kidney Evaluation and Awareness Programme in Sheffield (KEAPS), is a general population screening programme, whilst Kidney Evaluation in Overweight Population in Sheffield (KEOPS) is a screening programme specifically for individuals with BMI >25.

RESULTS

The combined database had 1,179 subjects eligible for analysis after applying exclusion criteria. The prevalence of MA in subjects with BMI <25 was 3.1% compared to 12.1% in those with BMI 25-30 and 27.2% in obese subjects with BMI >30 (p < 0.001). The prevalence of MA increased exponentially with the BMI category. BMI is a predictor of MA in logistic regression analyses in the population as a whole, males, females, younger and older age categories, and higher BMI groups (above median and upper tertile). The effect of BMI persists after adjusting for confounding variables. The relative risk for having urine albumin concentration >20 mg/l is 8.0 (95% CI 3.8-16.8, p < 0.0001) if BMI is above the 80th percentile (BMI >27.2).

CONCLUSION

The prevalence of MA increases with increasing BMI in the population of Sheffield. The risk of having MA increases exponentially with BMI. The significance of the high prevalence of MA in overweight and obese individuals should be investigated longitudinally.