Translation, cultural adaptation and validation of the Salt Knowledge Questionnaire to the Spanish language

Abstract

Introduction: In order to reduce salt consumption in Spanish speaking countries it is necessary to know the level of salt knowledge in the population. However, there are no tools in Spanish to measure salt knowledge, but the only valid tool of measurement is the ‘Salt Knowledge Questionnaire’ (SKQ) developed in Australia, in English. Materials and methods: A validation study was conducted in three phases: (Phase 1) Translation of the original Australian version into Spanish; (Phase 2) Cultural adaptation based on a Spanish-speaking population such as Peru and following criteria used in the development of the original questionnaire which was evaluated by a panel of experts; (Phase 3) Construct validity by comparing the scores of three groups (experts, medical students and non-experts) and reliability by performing a test retest. Results: The translation of the SKQ into Spanish maintained a semantic equivalence with the original questionnaire and a panel of experts accepted the cultural adaptation. The SKQ enables discrimination between those who know and those who do not because differences of scores were found between the group of experts, students and non-experts (P <.001). A good overall internal consistency of the instrument was found (KR20 = 0.69) and a good overall intraclass correlation (0.79) and no test variations in test-retest (P >.05). Conclusions: The SKQ questionnaire in Spanish is valid, reliable and is a suitable first tool to measure knowledge about salt in the Spanish language. It is considered possible to adapt it culturally to the Spanish-speaking country that wishes to use it.