The differential association between history of childhood sexual abuse and body mass index in early and late stages of bipolar disorder

Background: History of distal stressors such as childhood trauma is a well-established, non-specific vulnerability factor for multiple mental illnesses. The objective of this study was to investigate the possible association between history of childhood trauma and body mass index (BMI) in individuals in early and late stages of bipolar disorder (BD) and to verify is there was any difference in the association of sexual abuse history and obesity in early versus late stages of BD. Methods: Seventy-one euthymic BD-type I patients and eighty-one healthy controls were evaluated using the Childhood Trauma Questionnaire (CTQ) and body mass index (BMI). The association between BMI and CTQ total and subscores were evaluated dividing BD population in early-stage BD-I (less than 10 years since onset of disease) or late-stage BD (more than 10 years). Results: BD individuals had higher rates of history of childhood trauma than HC, especially sexual and emotional abuse, after adjusting for confounders. We observed a moderating effect of group on the association between BMI and sexual abuse (SA), but not on other modalities of childhood trauma, after adjustments for age, gender, ethnicity, education, alcohol and tobacco use. Limitations: Our sample included a predominance of female individuals. The study cross-sectional design does not allow concluding a cause-effect relationship. In dividing the BD subgroups in relation with the time since the onset, we supposed that the natural course of BD is linear. The CTQ is subject to recall bias. Conclusion: There is a relationship between childhood sexual abuse and BMI, but the direction of the association varies across the different stages of BD-I.