Depression, anxiety and health status across different BMI classes: A representative study in Germany

Background: Changes in body mass index (BMI) over the course of one's lifetime are related to the development of mental disorders. In the current study we compared symptoms of depression, generalized anxiety as well as general health status in the four BMI-classes: underweight, normal weight, overweight and obesity. Furthermore, mediator role of general health status on the relationship between BMI and depression and generalized anxiety was analyzed. Methods: A representative sample (random-route sampling) of the German population (N = 2350) was investigated in a cross-sectional survey by measuring the three questionnaires PHQ-9, GAD-7 and EQ-5D-5L. Results: The results showed significant differences between the four BMI-classes in all three questionnaires. Individuals with obesity demonstrated higher values in depression, anxiety and general health compared to the three other BMI-classes. However, there was no U-shaped association between BMI and depression, anxiety and health-related quality of life. Regarding to the mediation analysis, general health status fully mediated the association between BMI, depressive symptoms as well as generalized anxiety symptoms. Limitations: The assessment of the three factors depression, anxiety and general health status were measured by questionnaires, but no clinical diagnoses can be provided. Conclusions: Evidence supports that individuals with obesity have an increased risk for depression and anxiety as well as lower general health. Further research on potential intervention and strategies in public health policies is needed to be able to target the developing of mental disorders in individuals with obesity. Taking their general health status into account is also of great importance.