Introduction: Shift work is often considered the one that takes place at night hours. It has been suggested that shift work may be related to various health problems, including body mass index increase with consequent development of overweight and obesity. The objective of this study is to review the existing literature on shift work and its relation with the body mass index (BMI) in health workers.Methods: A systematic review was made with information published in PUBMED database the last 10 years. It has been selected only the full text articles related to this topic in English, Spanish and Italian. Results: A total of 10 articles were found that met the defined inclusion criteria. Predominantly cross-sectional studies were obtained. Three of these studies found an association between current shift work and BMI increased. By contrast, two studies did not find this association. On the other hand, six studies agreed on a positive association between accumulated time in shift work and an increase in BMI.Conclusions: The results found in the analyzed studies point to the existence of a close relationship between the increase of the body mass index (BMI) with the night shifts (or shifts work that include night schedules) carried out by workers in a prolonged way, compared to workers who perform regular day shifts only.
