Background Dietary habits offer crucial information on one's health and form a considerable part of the patient-generated health data. Dietary data are collected through various channels and formats; thus, interoperability is a significant challenge to reusing this type of data. The vast scope of dietary concepts and the colloquial expression style add difficulty to standardizing the data. The interoperability issues of dietary data can be addressed through Common Data Elements with metadata annotation to some extent. However, making culture-specific dietary habits and questionnaire-based dietary assessment data interoperable still requires substantial efforts. Objective The main goal of this study was to address the interoperability challenge of questionnaire-based dietary data from different cultural backgrounds by combining ontological curation and metadata annotation of dietary concepts. Specifically, this study aimed to develop a Dietary Lifestyle Ontology (DILON) and demonstrate the improved interoperability of questionnaire-based dietary data by annotating its main semantics with DILON. Methods By analyzing 1158 dietary assessment data elements (367 in Korean and 791 in English), 515 dietary concepts were extracted and used to construct DILON. To demonstrate the utility of DILON in addressing the interoperability challenges of questionnaire-based multicultural dietary data, we developed 10 competency questions that asked to identify data elements sharing the same dietary topics and assessment properties. We instantiated 68 data elements on dietary habits selected from Korean and English questionnaires and annotated them with DILON to answer the competency questions. We translated the competency questions into Semantic Query-Enhanced Web Rule Language and reviewed the query results for accuracy. Results DILON was built with 262 concept classes and validated with ontology validation tools. A small overlap (72 concepts) in the concepts extracted from the questionnaires in 2 languages indicates that we need to pay closer attention to representing culture-specific dietary concepts. The Semantic Query-Enhanced Web Rule Language queries reflecting the 10 competency questions yielded correct results. Conclusions Ensuring the interoperability of dietary lifestyle data is a demanding task due to its vast scope and variations in expression. This study demonstrated that we could improve the interoperability of dietary data generated in different cultural contexts and expressed in various styles by annotating their core semantics with DILON.

BACKGROUND Dietary habits offer crucial information on one's health and form a considerable part of the Patient-Generated Health Data (PGHD). Dietary data are collected through various channels and formats; thus, interoperability is a significant challenge to reusing the data. The vast scope of dietary concepts and colloquial style of expression add difficulty to the standardization task. Common Data Elements (CDE) with metadata annotation and ontological structuring of dietary concepts address the interoperability issues of dietary data to some extent. However, challenges remaining in making culture-specific dietary habits and questionnaire-based dietary assessment data interoperable require additional efforts. OBJECTIVE The main goal of this study was to address the interoperability challenge in dietary concepts by combining ontological curation of dietary concepts and metadata annotation of questionnaire-based dietary data. Specifically, this study aimed to develop a Dietary Lifestyle Ontology (DILON) and demonstrated the improved interoperability of questionnaire-based dietary data by annotating its main semantics with DILON. METHODS By analyzing 1158 dietary assessment data elements (367 in Korean and 791 in English), 515 dietary concepts were extracted and used to construct DILON. To demonstrate the utility of DILON in improving the interoperability of multi-cultural questionnaire-based dietary data, ten Competency Questions (CQs) were developed that identified data elements that share the same dietary topics and measurement qualities. As the test cases, 68 dietary habit data elements from Korean and English questionnaires were instantiated and annotated with the dietary concepts in DILON. The competency questions were translated into Semantic Query-enhanced Web Rule Language (SQWRL), and the query results were reviewed for accuracy. RESULTS DILON was built with 260 concept classes and 486 instances and successfully validated with ontology validation tools. A small overlap (72 concepts) in the concepts extracted from the questionnaires in two languages indicates the need to pay closer attention to representing culture-specific dietary concepts. The SQWRL queries reflecting the 10 CQs yielded the correct results. CONCLUSIONS Ensuring the interoperability of dietary lifestyle data is a demanding task due to its vast scope and variations in expression. This study demonstrated that, when combined with common data elements and semantic metadata annotation, ontology can effectively mediate the interoperability of dietary data generated in different cultural contexts and expressed in various styles.