{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T09:14:04Z","timestamp":1783329244386,"version":"3.54.6"},"reference-count":14,"publisher":"Springer Science and Business Media LLC","issue":"8","license":[{"start":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T00:00:00Z","timestamp":1770768000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T00:00:00Z","timestamp":1770768000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/501100005003","name":"Baskent University","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100005003","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Pediatr Nephrol"],"published-print":{"date-parts":[[2026,8]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>The urinary calcium-to-citrate (Ca\/Cit) ratio has emerged as a useful indicator of lithogenic risk in older children; however, no reference data exist for infants and toddlers. This study aimed to evaluate whether the spot Ca\/Cit ratio can distinguish stone-forming from non\u2013stone-forming children under 24\u00a0months of age and to assess its diagnostic performance compared with conventional urinary markers.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      This retrospective single-center study included 181 children aged 1\u201324\u00a0months who underwent metabolic evaluation and ultrasonography at their first presentation to a tertiary pediatric nephrology clinic between 2012 and 2024. Based on urinary calcium excretion and ultrasonographic findings, participants were categorized as normocalciuric stone-free controls (\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u200957), hypercalciuric stone-formers (\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u200929), or non-hypercalciuric stone-formers (\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u200995). Spot urine calcium, citrate, and related biochemical ratios were analyzed. The diagnostic accuracy of the Ca\/Cit ratio for predicting stones was assessed using receiver operating characteristic (ROC) analysis.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      The Ca\/Cit ratio differed significantly across groups, with the highest levels observed in hypercalciuric stone-formers (0.46\u00a0mg\/mg) compared with controls (0.17\u00a0mg\/mg;\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.001) and non-hypercalciuric stone-formers (0.31\u00a0mg\/mg;\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.001). A Ca\/Cit threshold\u2009&gt;\u20090.23\u00a0mg\/mg (\u2248 1.10\u00a0mmol\/mmol) demonstrated moderate diagnostic ability for stone detection (AUC 0.695; 95% CI 0.613\u20130.785), yielding 66.1% sensitivity and 63.2% specificity. Age showed no meaningful correlation with Ca\/Cit values. Normocalciuric stone-free children provided an age-appropriate reference distribution for Ca\/Cit ratios.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>In infants and toddlers evaluated for suspected urinary stone disease, the Ca\/Cit ratio offers moderate discriminatory power and may serve as a practical adjunctive marker of stone risk. A ratio\u2009&gt;\u20090.23\u00a0mg\/mg (\u2248 1.10\u00a0mmol\/mmol) appears to indicate increased lithogenic potential. Larger prospective studies are needed to validate reference intervals and refine clinically applicable cut-off values for this young age group.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1007\/s00467-026-07191-z","type":"journal-article","created":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T21:11:57Z","timestamp":1770844317000},"page":"2499-2507","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Urinary calcium-to-citrate ratio predicts kidney stone risk in children under the age of two years"],"prefix":"10.1007","volume":"41","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7489-0136","authenticated-orcid":false,"given":"Utku","family":"D\u00f6nger","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5739-6590","authenticated-orcid":false,"given":"Meraj Alam","family":"Siddiqui","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0774-4419","authenticated-orcid":false,"given":"Aysun \u00c7alt\u0131k","family":"Y\u0131lmaz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9019-423X","authenticated-orcid":false,"given":"Caner","family":"\u0130nceka\u015f","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4361-8508","authenticated-orcid":false,"given":"Esra","family":"Bask\u0131n","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,2,11]]},"reference":[{"key":"7191_CR1","doi-asserted-by":"publisher","first-page":"1817","DOI":"10.1046\/j.1523-1755.2003.00917.x","volume":"63","author":"KK Stamatelou","year":"2003","unstructured":"Stamatelou KK, Francis ME, Jones CA, Nyberg LM, Curhan GC (2003) Time trends in reported prevalence of kidney stones in the United States: 1976\u20131994. 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