Urinary citrate excretion in healthy children depends on age and gender

Abstract

BackgroundHypocitraturia is considered a major risk factor for calcium stone formation. However, there is no widely accepted reference database of urinary citrate excretion in children. The aim of our study was to determine the amount of citrate eliminated in the urine over a 24-h period in a pediatric cohort and to determine an optimal unit reflecting excretion.MethodsThe study cohort comprised 2,334 healthy boys and girls aged 2–18 years. The levels of urinary citrate were assessed by an enzymatic method in 24-hour urine and expressed in absolute values, as urinary concentration, citrate/creatinine ratio, per kilogram of body weight, in relation to 1.73 m2, and as the calcium/citrate index.ResultsSimilar incremental age-related citraturia rates were observed in both male and female subjects until puberty during which time citrate excretion became significantly higher in girls. Urinary citrate adjusted for creatinine and for body weight showed a significantly decreasing trend with increasing age in both sexes. Urinary citrate corrected for body surface was weakly correlated with age. Thus, the assumption of 180 mg/1.73 m2/24 h for males and 250 mg/1.73 m2/24 h for females as lower cut-off values appeared to be reliable from a practical perspective.ConclusionsWe found distinct sex-dependent differences in citraturia at the start of puberty, with significantly higher values of urinary citrate in girls than in boys. Further prospective studies are warranted to elucidate whether this difference represents a differentiated risk of urolithiasis.

Influence of Sex on Urinary Organic Acids: A Cross-Sectional Study in Children

“…Specifically, urinary citrate levels increase with age only in females. According to this, boys excrete less citrate than girls, at the beginning of puberty, suggesting that citrate excretion could be influenced by sexual hormones [40]. The importance of sexual hormones is also confirmed by data obtained in pre and postmenopausal women [41][42][43].…”

Potassium‐sodium citrate prevents the development of renal microcalculi into symptomatic stones in calcium stone‐forming patients

“…Women typically excrete more citrate than men, as was shown in the present study by the average citrate excretion in women being higher than in men in the non-citrate group at both study initiation and at the 1-year follow-up point (P < 0.03 and P < 0.04, respectively, paired t-test). 26 The results also showed that there were no significant differences between the two patient groups with respect to the ratios of female patients experiencing microcalculi enlargement. In the non-citrate group, suppression of microcalculus enlargement was considered to be a result of high citrate excretion levels.…”

A case-control study on the risk factors of urinary calculus in Uyghur children in the Kashi region

“…Various domestic and international studies have confirmed that the etiology of UC is closely related to environmental factors (Finlayson, 1974;Embon et al, 1990;Leusmann et al, 1990), as well as to genetic factors, ethnicity, gender, age, dietary habits, urinary biochemical abnormalities, etc. (Siener, 2006;Park et al, 2010;Kirejczyk et al, 2014). Previous reports (Nishijima et al, 2002;Lin et al, 2011) have stated that polymorphism of the vitamin D receptor gene is also related to the development of UC.…”