Childhood maltreatment and obesity.

Abstract

The old idea that adverse psychosocial conditions during childhood have lasting influences on the risk of obesity, strongly promoted by Bruch (1), has recently proliferated. Last year the association between childhood maltreatment and risk of obesity was addressed in two systematic reviews and meta-analyses (2, 3). Both found robust evidence for the association with similar odds ratios (OR) for obesity; Danese and Tan (2) analyzed 41 studies with 190,285 participants and found an OR of 1.36 (95% confidence interval of 1.26–1.47), and Hemmingson et al. (3) analyzed 23 studies with 112,708 participants and found an OR of 1.34 (1.24–1.45), although both also found a considerable unexplained heterogeneity between studies. Hemmingson suggested that the ORs may have been underestimated because of the difficulties in proper assessment of childhood maltreatment, and he requested more prospective studies with independent proxy data on the maltreatment, as used in the study showing the highest OR (4). The results inspired Hemmingson (5) to propose a comprehensive model of the pathway from socioeconomic disadvantages through adult distress, disharmonious family environment, offspring distress, psychological and emotional overload, and disrupted homeostasis that initiates weight gain, which through its various consequences creates a reinforcing feedback promoting further weight gain. Most previous studies used only body weight (BMI) as measure of obesity; a few have additionally studied waist circumference or the waist/hip ratio and found the same association. On this background, the study by Li et al. in this issue (6) is particularly relevant because it examines the associations between childhood maltreatment and body composition and fat distribution. In a cross-sectional study of a convenience sample of 75 adults who reported on their history of childhood maltreatment by a validated questionnaire, Li et al. divided the participants according to the questionnaire scores into two equally sized groups, of which one was considered having suffered from childhood maltreatment. They could not replicate the findings from the meta-analyses regarding BMI and waist/hip ratio nor did they show an association with total fat mass, but given the study design and sample size, these results obviously do not challenge the outcome of the meta-analyses. The only statistically significant association was the intriguing one between childhood maltreatment and increased visceral fat mass. This may be stress-induced, which was also supported by the finding of a blunted cortisol awakening response and a corresponding elevation in inflammatory markers in the same group. To what extent these findings reflect the recent and concurrent psychosocial situation, possibly also influencing the responses to the childhood maltreatment questionnaire, needs to be explored. However, assuming no such confounding, the findings suggest that childhood maltreatment in some way leaves the participants either in chronic stress or with an increased sensitivity to stressors later in life. Besides the obvious demands to stop childhood maltreatment, irrespective of its health effects, the association of maltreatment to various forms of obesity invites research to elucidate the pathways and to find ways to block the effects on development and persistence of obesity, thereby facilitating both prevention and treatment of obesity.