Abstract
Objective
Transferability of questionnaires across languages and cultures requires a systematic process to preserve content integrity and ensure validity and reliability. The aim of this study was to translate, culturally adapt and face validate the US-developed patient-reported outcome (PRO) measure ‘Type 1 Diabetes and Life’ (T1DAL) for use in a Danish population of parents of children under the age of 11 years living with type 1 diabetes.
Design
The process followed the 10-step International Society for Pharmacoeconomics and Outcomes Research good practice principles for the translation and cultural adaptation of PRO measures, thereby establishing content validity and cross-cultural validity in accordance with COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) recommendations.
Results
Following approval from the developer of the original questionnaire, two independent forward translations were conducted by bilingual native Danish speakers. These translations were then synthesised into a reconciled version, which were then back translated by two bilingual native English speakers. Discrepancies between the original and the reconciled versions were reviewed, leading to small linguistic and cultural adjustments. This process included discussions around the response categories on the Likert-scale and items reflecting the US healthcare context—particularly those related to insurance-dependent access, which are less relevant in Denmark.
Cognitive debriefings regarding the updated Danish version with 12 parents resulted in a Danish version demonstrating strong semantic, conceptual and experiential equivalence. Additionally, minor linguistic and cultural adjustments were made to enhance clarity and contextual appropriateness. Cognitive debriefing confirmed the questionnaire’s acceptability and comprehensibility across a diverse range of respondents.
Conclusion
Applying ISPOR principles emphasised the importance of cultural adaptation that extends beyond linguistic translation to preserve the original questionnaire’s integrity and meaningfulness and resulted in a conceptually equivalent and culturally adapted Danish version of the original T1DAL questionnaire, suitable for use in Danish clinical and research settings.
Trial registration number
H-25016032
Keywords: Patient Reported Outcome Measures; Diabetes Mellitus, Type 1; Parents
Strengths and limitations of this study.
This Danish translation and cultural adaptation of the Type 1 Diabetes and Life questionnaire followed the structured process using the International Society for Pharmacoeconomics and Outcomes Research guidelines.
The Danish translation of the questionnaire was tested under cognitive debriefing, yet with a small sample size.
The translated and culturally adapted version still needs psychometric validation in a clinical Danish population.
Introduction
Type 1 diabetes in children requires intensive and ongoing management, which affects not only the child but the entire family.1 2 Parents often experience significant emotional, social and practical burdens that can diminish their quality of life.2 3 As treatments and daily management of type 1 diabetes continue to evolve, so too do the lived experiences and challenges faced by the families.4 Therefore, updated measurement tools are needed to accurately capture the current realities and quality of life of parents of children with type 1 diabetes.
Patient-reported outcome (PRO) measures are essential tools in clinical research and practice, enabling the quantification of subjective health-related experiences. Current International Society for Pediatric and Adolescent Diabetes guidelines recommend the use of validated tools to monitor and discuss psychological issues also with caregivers, without recommending a specific tool.2
Type 1 Diabetes and Life
The questionnaire ‘Type 1 Diabetes and Life’ (T1DAL) has recently been developed in the USA using a participatory design and provides a validated, diabetes-specific tool to assess health-related quality of life (HRQoL) in parents of children with type 1 diabetes. T1DAL enables clinicians and researchers to identify needs, monitor changes over time and design targeted interventions to support families living with type 1 diabetes.5 T1DAL was chosen because it is a condition-specific instrument designed to capture the impact of type 1 diabetes on family life from the caregiver perspective. In addition, it is developed in line with the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) recommendations and has demonstrated strong content validity.5 However, the transferability of PRO instruments across languages and cultures requires a systematic process to ensure the integrity of the original content is preserved, and thereby, the measure’s validity and reliability.6
This article presents the translation, cultural adaptation and linguistic validation of the parental version of the questionnaire T1DAL into Danish,5 strictly following the 10-step methodology established by the ISPOR Task Force.6 These guidelines represent the best practice for achieving conceptual, semantic and cultural equivalence when adapting instruments across contexts. The translation and cultural adaptation represent the first step in an ongoing research programme aimed at assessing the experiences and needs of Danish families with children aged ≤11 years with type 1 diabetes.
Our aim was to translate, culturally adapt and face validate the US-developed PRO measure T1DAL for use in a Danish population of parents of children under the age of 11 years living with type 1 diabetes and to ensure the translated T1DAL questionnaire would retain its original psychometric properties and be culturally meaningful to Danish respondents.
Methods
Reporting of the study adheres to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) reporting guideline for studies on measurement properties of PROs.7 According to COSMIN, adequate cross-cultural validity and content validity of an instrument in a new language must be established before psychometric testing. This study addresses this requirement, while psychometric evaluation is reported separately.
T1DAL
The T1DAL questionnaire measures type 1 diabetes-specific HRQoL and includes several versions for parents, partners and people with diabetes (PwD) including children living with type 1 diabetes aged <8 and 8–11 years; as well as for adolescents aged 12–17 years; young adults aged 18–25 years; and for partners of adults living with type 1 diabetes.5 Each version was developed to address specific aspects of HRQoL relevant to the life stage of the person living with diabetes and the responder type (PwD, parents or partner).
T1DAL measures are scored on a 5-point Likert scale (rated 0–4). Positively worded items were scored 0=0, 1=25, 2=50, 3=75 and 4=100 (mean multiplied by 25). Negatively worded items were scored in reverse. A higher T1DAL score indicated higher diabetes-specific HRQoL over the last 4 weeks.5
This study only includes the translation and validation of the parental version <8 and 8–11 years. The two questionnaire versions (<8 and 8–11 years) were combined to ensure continuity across the age range and to facilitate future use of a single instrument in both clinical practice and research. This approach supports comparability while preserving the conceptual content of the original instrument. The version for parents with children under the age of 8 years includes 27 items, and the version for parents with children aged 8–11 years includes 22 items. The two versions include some similar and some different subscales/conceptual categories.5 The combined version consisted of 37 items before reduction based on psychometric analysis.
Study settings, participants and recruitment
The study was conducted at Steno Diabetes Center Copenhagen. Participants (for the cognitive debriefing) were recruited in connection with a Danish clinical group-based education setting, developed specifically for children with type 1 diabetes and their parents. While no formal exclusion criteria were applied beyond the ability to read and understand Danish, participants were required to be parents or primary caregivers of children aged ≤11 years with type 1 diabetes.
Guiding frameworks
The translation and adaptation process systematically followed the principles of good practice using the 10-step process of the ISPOR Task Force6:
Step I: preparation
The project group obtained permission to use the questionnaire, and a translation protocol was developed in collaboration with the instrument developer. The conceptual definition of each item and intended measurement objectives were clarified. A Danish project coordinator was appointed to oversee the process and ensure compliance with ISPOR guidelines, and a cognitive debriefing guide was developed in advance to facilitate standardised face validation procedures.
Step 2: forward translation
Two independent forward translations from English to Danish were conducted by bilingual native Danish speakers with different professional backgrounds (one clinical/medical, one non-medical with a lay perspective (T1 and T2)). This aimed to balance clinical fidelity with everyday language usage.
Step 3: reconciliation/synthesis
A synthesis of the two forward translations was created by the translators and the project coordinator, resolving discrepancies and creating a single reconciled version. This step emphasised semantic and conceptual equivalence over literal translation.
Step 4: back translation
Two native English speakers (T3 and T4), one layperson and one clinician, who were fluent in Danish and blinded to the original questionnaire independently translated the reconciled Danish version back into English. This step served as a quality check to detect potential deviations in meaning or nuance.
Step 5: back translation reviews
The project team reviewed all the translations, back translations and original instrument. This review focused on ensuring:
Semantic equivalence (meaning of words).
Idiomatic equivalence (colloquialisms).
Experiential equivalence (relevance of experiences).
Conceptual equivalence (meaning of underlying concepts).
Discrepancies between the original and the reconciled translation were discussed, translations were either preserved, rephrased or back translated again, whereafter consensus was reached on all items and a pre-final Danish version was produced.
Step 6: harmonisation
While this step typically applies to multilingual projects, harmonisation ensured internal consistency across translations by allowing the developer of the original T1DAL questionnaire to review and comment on the English back-translated questionnaire. No conflicting elements were identified.
The Danish version consists of a combination of the two original T1DAL parent questionnaires (0–8 years and 8–11 years). The questionnaires were merged to ensure that all respondents were presented with the same set of relevant items across age groups, including items concerning parents’ peer-to-peer interactions, which were originally included only in the 8–11 years version to ensure comprehensive coverage for parents of children aged 0–10 years and to align the Danish version with other age-group–specific T1DAL versions. This harmonisation process has been validated, although the validation has not yet been published.
Step 7: cognitive debriefing
The pre-final Danish version was tested in one large focus group with 12 participants from the target population (parents of children with type 1 diabetes aged up to 11 years old, mixed gender and diverse educational levels) by the project coordinator. The participants were unfamiliar with the project coordinator, who introduced herself as project coordinator and researcher, working in the children and adolescent clinic. The project coordinator wore casual clothing to reduce the risk of bias by talking to a clinician during the debriefing.
None of the participants had any prior knowledge of the T1DAL questionnaire.
First, the group was informed of the context and plan, and then each participant was given time to read the questionnaire and give written feedback of response options, each element, item, theme/concepts and the overall experience.
Afterwards, semi-structured focus-group cognitive debriefing was conducted to explore:
Comprehension of item wording.
Cultural relevance and acceptability.
Interpretability of response scales.
Participants took approximately 15–20 min to read, fill, and comment on the questionnaire in total and of each element.
The debriefing lasted for 60 min and revealed strong comprehension and relevance across all items. Minor changes were made to improve idiomatic naturalness.
Step 8: review of cognitive debriefing results and finalisation
All feedback from cognitive debriefing was reviewed by the project team. Based on this input, the pre-final version was refined. Final adjustments were made to enhance clarity without altering meaning.
Step 9: proofreading
The final Danish version was proofread to ensure grammatical and typographical accuracy.
Step 10: final report
A comprehensive translation report was compiled, documenting every step of the process, including rationales for decisions, translator notes, debriefing summaries and final revisions. This ensures transparency, reproducibility and traceability.
Ethics approval and consent to participate
This study is a part of a larger study. The full protocol was reviewed and approved by the Danish Data Protection Agency (approval number p-2024-17600). The study did not require ethical approval from the Regional Ethical Committee for the Capital Region on health research ethics in Denmark (registration number H-25016032). Oral and written consent for each participant was obtained before participant review and debriefing.
Patient and public involvement
None.
Results
Translation and harmonisation
The translation process was systematically planned and executed from January to May 2025. All items were successfully translated and adapted without loss of conceptual meaning.
Adjustments after translation and harmonisation included:
-
Substitution of culturally specific healthcare system references:
several items were identified as reflecting the US healthcare system—particularly those concerning insurance-dependent access to care and personal healthcare costs. In the Danish healthcare context, direct medical costs are largely covered by the public system; however, families may still experience indirect or broader financial burdens. Therefore, wording adjustments were required to preserve conceptual equivalence. With approval from the original questionnaire developer, items referring to ‘costs’ were rephrased to explicitly address their own diabetes-related financial costs, thereby excluding costs covered by the Danish government. The revised wording (‘financial costs’) was chosen to reflect this more explicitly and ensure that respondents interpret the item consistently within the Danish context. As an example, an item was changed to ‘Our family has had to give up a lot due to the financial costs of my child’s diabetes treatment’ instead of ‘Our family has had to give up a lot because of the cost of my child’s diabetes care’.
Another item required modification due to its explicit reference to the US insurance system. The original wording – ‘I have to work in a job that I do not like to maintain good insurance to help with my child’s diabetes’ – reflects employment decisions driven by the need to secure adequate private health insurance. In the Danish context, healthcare coverage is not dependent on employment status, and the underlying intention of the item risked being misunderstood. To preserve the conceptual meaning—that parents may remain in an undesired work situation to ensure the best possible support for their child’s diabetes management—the item was reformulated with approval from the original questionnaire developer to: ‘I have to work in a job that I do not like because it gives me the possibility to help with my child’s diabetes’.
This modification removes the culturally specific dependency on employer-linked insurance while maintaining the core construct relating to the impact of a child’s illness on parental employment decisions.
-
Modification of response option wording to align with Danish usage norms:
during the translation process, several response options were discussed and revised to ensure natural and culturally appropriate Danish wording. For example, the original English term ‘argue’ was discussed to determine whether the Danish ‘skændes’ (quarrel) or ‘diskuterer’ (discuss) better reflected the intended meaning. Additionally, pronouns and possessive forms were standardised: ‘You/your’ was adapted to ‘din/dine’ or ‘jer/jeres’, depending on context, to match Danish grammatical norms and enhance clarity.
No major conceptual challenges were encountered, and the back-translations were highly consistent with the original source.
Cognitive debriefing and finalisation
Cognitive debriefing confirmed relevance and participant understanding without confusion or misinterpretation. Participants, in general, reported high relevance, clarity and ease of understanding. Specific feedback led to minor changes in five items or headers to ensure comprehensiveness, enhance naturalness and acceptability in the Danish context.
First, participants were asked to answer the questions on a 5-point Likert scale. All parents commented on the categories and suggested a less wordy version. This led to modified response options to align with typical Danish use. For example, ‘No, not at all true’ was adapted to ‘No, never’, ‘Sometimes yes and sometimes no’ was adapted to ‘sometimes’.
Second, a few wordings in some of the items were also found to be confusing. Participants suggested adding some extra words to help understand what is meant, especially items on family or diabetes team. For example, within family, participants suggested ‘For the following questions, please think of everyone you consider to be a part of your family in your daily life’ instead of ‘For these questions, please think about anyone you think of as part of your family’. Another example was ‘We have extended family network (for example grandparents or close friends) who are supportive/helpful’ instead of ‘We have extended family who are supportive/helpful’.
Third, the participants asked for an additional subtext for the subheadings. For example, for items in ‘diabetes and other people/relationships’ without any original subtext, the participants suggested ‘For the following questions, please think of people in your network, other than those in your immediate family’. Within ‘My child’s diabetes healthcare’, participants suggested to include the following new subtext ‘For the following questions, please think of your child’s diabetes treatment and his/her relationship with the diabetes treatment team’ to make sure the focus was on the diabetes clinic and the healthcare provider team and not including teachers or others supporting the child and family.
No items were found to be culturally inappropriate. Overall, participants reported that the questionnaire was relevant and comprehensive, as it focused on essential factors of life with a child living with diabetes. The process supported the content validity of the Danish version in accordance with the COSMIN standards.
A comprehensive translation report and version control history were maintained throughout, as per ISPOR recommendations, ensuring full traceability (see online supplemental material A).
Discussion
This study describes the systematic translation, cultural adaptation and face validation of the parental version of the T1DAL questionnaire into Danish, conducted in accordance with the 10-step ISPOR good practice principles for the translation and cultural adaptation of PRO measures. The findings demonstrate that a rigorous, structured approach enables preservation of the conceptual integrity of a US-developed instrument while ensuring cultural relevance and acceptability in a Danish healthcare context. This study highlights the importance of following a structured guide when translating between languages and cultures. The multistep process by using the ISPOR guidelines led to a high-quality Danish adaptation of the US PRO instrument T1DAL that emphasised both linguistic accuracy and cultural relevance, ensuring the integrity of the measure across languages and the need for cultural adaptation.
Cultural adaptation extended beyond literal linguistic translation. Several items in the original T1DAL questionnaire reflected features of the US healthcare system, particularly insurance-dependent access to care and employment-related insurance considerations. These constructs are largely absent in the Danish healthcare system, where diabetes-related care and treatment costs mostly are publicly funded. Direct translation of such items would therefore have risked conceptual distortion or misunderstanding. Through close collaboration with the original instrument developer and guided by ISPOR principles, these items were reformulated to preserve their underlying intent, namely the impact of a child’s diabetes on family finances and parental employment decisions, while removing culturally specific references. This process highlights the importance of addressing experiential and conceptual equivalence, not merely semantic equivalence, when adapting PRO measures across healthcare systems.
The cognitive debriefing further supported the cultural relevance and comprehensibility of the Danish T1DAL version. Only minor adjustments were required, primarily related to naturalness of phrasing and simplification of response option wording to align with Danish usage norms. These findings suggest that many of the challenges captured by the original T1DAL, such as emotional burden, family dynamics, and interactions with healthcare teams, are broadly shared across cultural contexts. This aligns with the participatory design underpinning the original T1DAL development, which aimed to capture the universal aspects of diabetes-related quality of life among parents of children with type 1 diabetes.
Strengths include the use of dual independent translations, expert and original developer review, and empirical validation through cognitive debriefing. The project also adhered to a rigorous documentation process, enhancing auditability. This strengthens the credibility of the Danish version and facilitates future adaptations, comparisons and psychometric evaluations.
Limitations include a relatively small sample size for the cognitive debriefings. However, this is consistent with ISPOR recommendations for qualitative testing of translated instruments, and the high consistency of feedback across participants suggests adequate coverage of key issues related to comprehension and relevance. Adapting and combining age-specific versions may introduce a limitation, as certain items may be interpreted differently depending on the child’s developmental stage. While care was taken to preserve conceptual equivalence during translation and adaptation, minor age-related differences in relevance or interpretation cannot be excluded. Further work is needed to translate and linguistically validate other T1DAL versions targeting other age groups and respondent types. Finally, this study did not evaluate the psychometric properties. Linguistic or face validation is a necessary but distinct step that precedes psychometric testing, and the present findings provide a foundation for such evaluations rather than a substitute for them. Following this validation, psychometric evaluation using Rasch analysis is required to assess item functioning, dimensionality and measurement invariance across age groups.7 This will be addressed in a subsequent study.
Conclusion
Following 10-step good practice framework of ISPOR enabled the production of a linguistically valid and culturally adapted Danish version of the original PRO instrument T1DAL. The new Danish tool is now ready for field testing and broader application in Danish clinical research and patient care. Psychometric validation will be essential to confirm its reliability and structural validity in this population, further supporting its clinical and research applications.
Supplementary material
Acknowledgements
The authors would like to thank: The participating parents, the rest of the project group for their contributions; Christina van Elst (second forward translator), Nanja Holland and Maria Campbell (back translators), Lene Lyngsøe (part of the synthesis), and the co-developer and first author of the original T1DAL questionnaire Marissa Hilliard.
Footnotes
Funding: All authors are employed at Steno Diabetes Center Copenhagen, a public university hospital and research institution under the Capital Region of Denmark, which is partly funded by a grant from the Novo Nordisk Foundation. This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
Prepublication history and additional supplemental material for this paper are available online. To view these files, please visit the journal online (https://doi.org/10.1136/bmjopen-2026-121311).
Provenance and peer review: Not commissioned; externally peer reviewed.
Patient consent for publication: Consent obtained directly from patient(s).
Ethics approval: This study is a part of a larger study. The full protocol was reviewed and approved by the Danish Data Protection Agency (approval number p-2024-17600). The study did not require ethical approval from the Regional Ethical Committee for the Capital Region on health research ethics in Denmark (registration number H-25016032). Oral and written consent for each participant was obtained before participant review and interviews. Participants gave informed consent to participate in the study before taking part.
Data availability free text: Not applicable.
Patient and public involvement: Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Data availability statement
Data sharing not applicable as no datasets generated and/or analysed for this study.
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