Relationship between depression scores and all - cause mortality in an obese population: a cohort study

Background: Depression is a grave global mental - health issue, commonly found among obese individuals. Obesity and depression are mutually interactive. Thus, investigating their association with all - cause mortality holds substantial significance. Methods: Using NHANES data from 2005 to 2018 in the United States, 9542 obese participants were screened out from 28047 participants. Depressive symptoms were assessed using the PHQ-9, while all-cause and cardiac death served as the outcome indicators. Covariates were accounted for in the analysis through different statistical techniques. Results: 1,761 participants were diagnosed with depression. Depressed patients and non - depressed patients differed significantly in several aspects.The PHQ-9 score was non-linear with all-cause mortality, with a threshold of 6. When the score was lower than 6, the all-cause mortality effect was significant. When it was higher than 6, there was no significant effect. Age, race and other factors influenced the relationship. A significant correlation was found between the depression score and all-cause mortality among people aged 60 or younger, particularly in non-Hispanic Black individuals. Conclusion： In the obese population, the PHQ - 9 score and all - cause mortality exhibit a non - linear association. When the score was lower than 6, the all-cause mortality effect was significant. When it was higher than 6, there was no significant effect.