[Relationship between spot urine pH and number of metabolic syndrome features].

ABSTRACT

A significant inverse relationship between the 24-hour urine pH and number of metabolic syndrome (MS) features(BMI ≥ 30 kg/m2, circumference > 88cm, HDL-cholesterol < 50mg/dL, etc.) was identified in individuals, which means that 24-hour urine pH values decrease with an increasing number of MS features. In this respect, we examined the association between the number of MS features and spot urine pH instead of 24-hour urine pH. A positive relationship was observed between the spot urine pH and number of MS features by analysis of covariance, with the age, gender, and eGFR as covariates. On the other hand, a high level of serum uric acid (UA) indicated a significantly lower spot urine pH compared with a normal level of UA. Serum UA was a significant independent variable explaining the decrease of the urine pH. The results of path analysis showed that UA had negative effects on the number of MS features and urine pH. Therefore, a positive relationship between the number of MS features and urine pH will be a spurious correlation with UA as a confounding factor. In addition, the negative relationship between the number of MS features and UA was also a spurious correlation with age as a confounding factor. From these results, the serum UA level should be considered to evaluate the relationship between the number of MS features and spot urine pH.