The effect of sex, height and time of day on the excretion of glycosaminoglycans and the consequences

A diurnal rhythm in the excretion of glycosaminoglycan-derived uronic acid with an increased excretion during daytime has been found in adults. Due to this rhythm a 24-h excretion was established as the optimum measurement of glycosaminoglycan turnover in tissue. Neither the excretion of uronic acid nor the uronic acid creatinine ratio in the morning urine could predict the 24-h excretion of glycosaminoglycans as estimated by a statistical model. This model may also be of general interest in similar clinical problems. Compared with males, females had a lower excretion of glycosaminoglycans. Part of this discrepancy reflected a sex-difference in height, which was shown to be positively correlated with the excretion. On the other hand, the uronic acid creatinine ratio was not influenced by height or sex. Body mass, age and urine output did not influence the ratio or the excretion of uronic acid.