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This study evaluated the psychometric properties of the Quality of Life of Parents of Children with Achondroplasia (QOLA) questionnaire in three European settings.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      A multinational, multicentre observational psychometric validation study was conducted in Germany, Italy, and Portugal. Parents\/primary caregivers (\n                      <jats:italic>N<\/jats:italic>\n                      \u2009=\u2009149) completed the 43-item QOLA (eight conceptual domains) and the EUROHIS-QOL-8 at baseline (T1); a subsample completed follow-up assessments (T2;\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u200977) for test\u2013retest analyses. Data quality (missingness, floor\/ceiling effects), internal consistency (Cronbach\u2019s \u03b1; composite reliability), temporal stability (Pearson correlations; intraclass correlation coefficients), and convergent validity (correlations with EUROHIS-QOL-8) were examined. Exploratory factor analysis informed item reduction and domain aggregation, followed by confirmatory factor analysis of the reduced model.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Item-level missingness was minimal, and no substantial floor\/ceiling effects were observed. Eight-domain scores showed acceptable to excellent internal consistency (\u03b1\u2009=\u20090.706\u20130.905) and moderate-to-good temporal stability (single-measure ICCs = 0.64\u20130.75). Convergent validity was supported by negative associations between QOLA domains and generic QoL (\n                      <jats:italic>r<\/jats:italic>\n                      = .15\u20130.69). Exploratory and confirmatory analyses supported a parsimonious three-factor, 20-item model, comprising Healthcare System Trust, Caregiving Burden and Daily Impact, and Worries About the Future and Social Relationships, with acceptable fit (CFI = 0.935, TLI = 0.925, RMSEA = 0.066), strong reliability (\u03b1\u2009=\u20090.852\u20130.918; CR = 0.864\u20130.914), and good test\u2013retest stability (\n                      <jats:italic>r<\/jats:italic>\n                      = .670\u20130.782; average-measure ICCs = 0.801\u20130.877).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The QOLA demonstrates robust reliability and validity across three countries and offers both an eight-domain profile and a three-factor summary for assessing parental QoL in achondroplasia.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s41687-026-01207-w","type":"journal-article","created":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T03:26:18Z","timestamp":1790306778000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The QOLA study: psychometric validation of the Quality of Life of Parents of Children with Achondroplasia (QOLA) questionnaire - a multinational study in Germany, Italy, and Portugal"],"prefix":"10.1186","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4828-1529","authenticated-orcid":false,"given":"Adekunle","family":"Adedeji","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6143-7594","authenticated-orcid":false,"given":"Stefanie","family":"Witt","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lea","family":"Maric","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Salomao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Florian","family":"Innig","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"In\u00eas","family":"Alves","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chiara","family":"Provasi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marco","family":"Sessa","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5113-8657","authenticated-orcid":false,"given":"Klaus","family":"Mohnike","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0876-4211","authenticated-orcid":false,"given":"Julia","family":"Quitmann","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,9,25]]},"reference":[{"key":"1207_CR1","doi-asserted-by":"publisher","unstructured":"Adedeji A, Witt S, Salom\u00e3o M, Steinhoff T, Innig F, Alves I, Provasi C, Sessa M, Mohnike K, Quitmann J (2026) Development and pilot testing of the quality of life of parents of children with achondroplasia questionnaire. 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That directly addresses the journal\u2019s concern. I would revise it to: All procedures involving human participants were conducted in accordance with the ethical standards of the responsible institutional research ethics committees and with the principles of the Declaration of Helsinki and its subsequent amendments. All participants provided written informed consent prior to participation. The study was reviewed and approved by the Local Psychological Ethics Committee (LPEK) of the Centre for Psychosocial Medicine, University Medical Center Hamburg-Eppendorf, Germany (approval number: LPEK-0354). Ethical approval for the conduct of the study was also obtained from the Italian Association for the Knowledge and Study of Achondroplasia (AISAC) in Italy and the National Association for Skeletal Dysplasias (ANDO) in Portugal. Data collection across the participating countries was centrally coordinated under the approved study protocol. In Italy, AISAC facilitated participant recruitment, and in Portugal, ANDO facilitated participant recruitment. The same study procedures were implemented across participating countries, and no separate data collection protocols were introduced by the participating organisations. All study procedures in Germany, Italy, and Portugal were conducted in accordance with the approved study protocol, the respective ethical approvals, and the principles of the Declaration of Helsinki and its subsequent amendments.","order":1,"name":"Ethics","label":"Ethics approval and consent to participate","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors declare no competing interests.","order":2,"name":"Ethics","label":"Competing interests","group":{"name":"EthicsHeading","label":"Declarations"}}],"article-number":"170"}}