Development of an Objective Nutritional Well-Being Index for the Quantitative Assessment of Metabolic Health Based on 16 Items

Background: The current trend to develop precision medicine/nutrition tools to assess well-being calls for the inclusion and objective assessment of the associations between lifestyle and health related quality of life (HRQoL) as drivers of health and disease. Therefore, our study aimed to estimate predictors of Short-Form 36 questionnaire (SF-36) through pondered lifestyle features and develop a nutritional well-being index (NWB-i) and to objectively classify NWB-i scores according to self-perceived health (SPH). Methods: In this cross-sectional analysis of 14,969 individuals, multivariate linear regression models using the leave-one-out method were conducted to predict HRQoL through key demographic and lifestyle characteristics. Two optimal cut-offs were defined to classify individuals according to SPH based on a receiver operating characteristic (ROC) curve and area under the curve (AUC) analyses; sensitivity and specificity were optimized (Youden Index), while a distribution-based method was used to identify poor and excellent SPH. Findings: Metabolic well-being was adequately estimated using 16 lifestyle and nutritional items (adjusted R-squared: 0·47, p<0·001). The tool was capable of identifying SPH in a satisfactory manner for the lower cut-off (set to 75 points, AUC was 0·81 (95% CI: 0·79, 0·83); sensitivity 71·0%, specificity 77·2%), and the upper cut-off (set to 81 points, AUC was 0·67 (0·66, 0·69); sensitivity 63·2%, specificity 61·2%). Interpretation: Sociodemographic, nutritional and lifestyle determinants can be weighted to objectively assess well-being as demonstrated by the tool developed in this study. Standard cut-off values allow for a clear identification of subjects at risk, their precluding features, but ultimately as proof of their applicability to the assessment of well-being. Funding: Funding was received from the Spanish Government-Instituto de Salud Carlos III, the European Regional Development Fund (FEDER) (RD 06/0045, CIBER-OBN, Grants PI10/02658, PI10/02293, PI13/00615, PI14/01668, PI14/01798, PI14/01764, PI17/01795, PI10/00564 and G03/140), the Navarra Regional Government (27/2011, 45/2011, 122/2014), and the University of Navarra. Declaration of Interest: None to declare. Ethical Approval: This study was approved by the Research Ethics Committee of the University of Navarra (2001/03) in line with the principles of the Declaration of Helsinki.