Assessment of the relationship between shift work and body mass index in petrochemical staff using latent growth curve model

Nowadays, obesity is considered as one of the health problems that increasess the risk of some diseases. So, identifying the effective factors on obesity is of great importance. Some researchers believe that shift work is one of the indicators for increasing the risk of obesity in society. This study aimed to investigate the relationship between the shift work and body mass index (BMI) in petrochemical staff. This study was performed on 3801 petrochemical staff who had fixed shift work during 2008-2011. These staff were referred to the occupational medicine center annually and their weight and height measured by trained nurses as a part of their periodical examinations. In this research, the latent growth curve model was used as one of analytical method for longitudinal data in order to assess the relationship between shift work and body mass index. Our findings showed that body mass index of all personnel significantly increases with the mean slope of 0.24 (p< 0.001). Also, the average annual trend of BMI in shift workers was about 0.122 higher than day workers (p<0.001). This study showed a significant relationship between shift work and BMI. More researches are needed for investigating the causes of this relationship and presenting strategies to prevent rising in BMI.