Objective: Depression and obesity are two conditions with great impact over global health. This is mainly due to their high prevalence and the morbidity and mortality associated to both. The main aim of the present systematic review is to study the association between obesity and depression and the prognostic implications derived from it. Methods: A literature review was performed in the PUBMED database. 18 articles were found (9 cross-sectional studies, 6 longitudinal studies and 3 clinical trials), which were reviewed by critical reading after which a summary of the main conclusions was written. Results: These selected articles confirmed that there is indeed a link between depression and obesity, although there are doubts as to the significance of this relationship. Depression is a risk factor for obesity, especially atypical depression and in African-American adolescent males. Obesity is a risk factor for depression, especially in women and for recurrent depressive disorder. The comorbidity between obesity and depression is a risk factor for a bad prognosis illness. Conclusion The relationship between both disorders has been analysed in scientific literature, obtaining significant associations but also contradictory results. The most current data demonstrates that there is a relationship between both entities, although there is no unanimity when it comes to establishing the meaning of this association.

Background: The Work Ability Index (WAI) is an instrument that measures work ability. The wide dispersion of the WAI internationally has led to its adaptation for use in different countries. This study aimed to evaluate the psychometric properties of the Spanish version of the WAI. Methods: A methodological design was used over an opportunistic sample of 233 workers in the aeronautical industry in Spain. Reliability was evaluated through internal consistency. Factorial validity, known groups, and convergent validity were tested. Results: The Cronbach's alpha and item-total correlation indicated an adequate internal consistency. The confirmatory factor analysis, performed to evaluate the factorial validity, found adequate fit indices for a two-factor solution with a high correlation between the factors. Factor 1, “Subjectively estimated work ability and resources”, was composed of 3 subscales and factor 2, “Ill-health-related”, of 2 subscales. Subscales 4 and 6 had loading in both factors. Workers under 45 years of age obtained higher significant scores than older ones. Convergent validity was also evidenced since WAI was highly correlated with self-assessment of health status. Conclusions The Spanish version of the WAI has shown evidence of reliability and validity in this study, supporting its use in individual and collective health surveillance by occupational health professionals. The factorial solution that was found has previously been reported in another international context. However, further research is needed to resolve the discrepancies detected in the role of some subscales between other national and international studies.