Sex differences in the relation between 24h urine volume and osmolality (LB710)

Twenty-four hour (24h) urinary hydration biomarkers have value in assessing hydration and disease risk. Specifically, highly concentrated urine and low urine volume increase relative risk for lithiasis and chronic kidney disease, respectively, and thus maintaining a high volume of dilute urine has been suggested as a simple preventive measure. Although there is a strong inverse relationship between 24h urine osmolality (UOsm) and volume (UVol), sex differences in urine concentration have been reported. This suggests the possibility of sex differences in the UOsm:UVol relationship which have not been fully explored. Our aim was to assess sex differences in the relationship between UOsm and UVol, and to determine whether body mass may explain any observed differences. METHODS: 24h urine samples from 238 healthy American and French adults (50% men; age 28±6 y; BMI 22.9 ± 2.6 kg∙m-2) were analyzed for UOsm and UVol. Sex differences in the UVol:UOsm relationship were evaluated with linear regression. RESULTS: ...