High-normal blood pressure is associated with microalbuminuria in the general population: the Watari study

Microalbuminuria, for which hypertension and diabetes are well-known risk factors, has recently been used to detect individuals at risk for cardiovascular and chronic kidney diseases in the general population. We aimed to determine the thresholds of blood pressure or blood glucose concentration at which the odds ratio of having microalbuminuria begins to increase. An annual public health checkup was conducted on 3166 participants aged 29-84 years (mean, 61±11 years; 40% men) living in Watari town, Japan. We studied their demographic data, medical history of hypertension, diabetes, dyslipidemia, sitting blood pressure and fasting blood samples. Urinary albumin excretion was examined in terms of the albumin/creatinine ratio in spot urine samples. Microalbuminuria was defined as 30-299 mg albumin per gram creatinine. Final analyses included 2133 participants under no anti-hypertensive or anti-diabetic medication. Microalbuminuria was detected in 118 subjects (5.5%). We used the adjusted odds ratios for microalbuminuria in different blood pressure and blood glucose groupings as the reference. The adjusted odds ratio increased linearly with increase in systolic blood pressure. A similar trend, although not as linear, was observed with diastolic blood pressure. The odds ratio increased significantly with high-normal levels of both systolic and diastolic blood pressure. For blood glucose, the adjusted odds ratio increased significantly from the impaired fasting glucose level. Therefore, the odds ratio for microalbuminuria begins to increase from high-normal blood pressure and impaired fasting glucose levels in comparison with the reference. Early intervention in such cases may be useful for reducing cardiovascular and renal risks.