Validation of questionnaires for the measurement of health variables: Fundamental concepts

In clinical practice and population health, it is common to use questionnaires to assess conditions or variables that are not directly observable. However, the construction and validation of these instruments or questionnaires are often poorly understood. This narrative review aims to summarize in a general way the process of construction and validation of these questionnaires in order to have a better understanding of this process, the aspects that are evaluated, and the best way to use them. The validation of questionnaires corresponds to a process of analysis of the questionnaire, aiming to measure a latent variable and its dimensions, which cannot be observed directly. A latent variable can be inferred through a set of specific attributes that are part of it, such as the items of a questionnaire, which are observable. Through a narrative review, this article addresses the fundamental concepts of questionnaire or test validation, latent variables or constructs, reliability and validity studies, and the factors that theoretically affect the latter two characteristics. Examples of these concepts are presented in the text.

Diabetes, periodontitis, and cardiovascular disease: towards equity in diabetes care

Type 2 diabetes and its associated cardiovascular risk is an escalating epidemic that represents a significant public health burden due to increased morbidity and mortality, disproportionately affecting disadvantaged communities. Poor glycaemic control exacerbates this burden by increasing retinal, renal, and cardiac damage and raising healthcare costs. This predicament underscores the urgent need for research into cost-effective approaches to preventing diabetes complications. An important but often overlooked strategy to improve metabolic control in diabetic patients is the treatment of periodontitis. Our aim is to assess whether the inclusion of periodontitis treatment in diabetes management strategies can effectively improve metabolic control, and to advocate for its inclusion from an equity perspective. We conducted a comprehensive review of the literature from 2000 to 2023. We analyzed the pathophysiological links between periodontitis, diabetes, and atherosclerotic cardiovascular disease, all of which have inflammation as a central component. We also examined the inequalities in health care spending in this context. Our findings suggest that incorporating routine screening and treatment of periodontitis into national health programs, with coordinated efforts between physicians and dentists, is a cost-effective measure to improve metabolic control, reduce complications and improve the overall quality of life of people with diabetes.