Age effects in eating disorder baseline risk factors and prevention intervention effects

Examine the impact of age on baseline eating disorder symptoms/risk factors and on the effects of completing three variants of an eating disorder prevention program.

Six hundred and eighty women (60% White) were randomized to clinician-led Body Project groups, peer-led Body Project groups, an Internet-based version of the Body Project (eBodyProject), or educational video control condition. Participants, who were on average 22.2 years old (SD = 7.1, range 17-64, median = 19), were assessed at pretest, posttest, and 6-month follow-up.

Two of the seven baseline variables were significantly associated with age, indicating that older age was associated with lower reported dieting (r = -.12) and better psychosocial functioning (r = -.13). Interactions indicated that age moderated the intervention effects, such that group-based programs were superior to the Internet-delivered version in terms of eating disorder symptom reductions for women up to age 20, whereas the Internet-delivered program was superior to group-based interventions, particularly in terms of BMI reduction, for women over approximately age 25. None of the four tests examining whether age moderated the effects of delivering Body Project groups by mental health clinicians versus undergraduate peer educators were significant.

Results suggest that group-based versions of the Body Project should be implemented with young women up to the age of 20, as they produce larger eating disorder symptom reductions, whereas the Internet version of the Body Project should be implemented with women aged 25 or older, as it produces superior weight loss/gain prevention effects.