Prospective Associations Between Driven Exercise and Other Eating Disorder Behaviors in Adolescence: A Longitudinal Cohort Study.

PURPOSE: Dysfunctional exercise is a common, debilitating symptom across eating disorders (ED). We examined the cross-sectional and longitudinal associations between experiences of exercise and ED behaviors and cognitions in an adolescent, population-based sample. METHODS: Adolescents (n = 4,054) self-reported whether they exercised to control shape and weight (exercise for weight loss [EWL]), and, if so, whether they exercised even when injured, and whether exercise interfered with life functioning (driven exercise) at age 14 years, allowing delineation of three exercise-based groups: no-EWL, EWL, and driven exercise. Participants also reported ED cognitions at age 14 years along with other ED behaviors (fasting, purging, binge eating) at ages 14 and 16 years. Sex-stratified regression approaches were employed to examine relationships between these exercise categories at age 14 and ED behaviors and cognitions at ages 14 and 16. RESULTS: Cross-sectionally, those in the driven exercise group, compared to the no-EWL group, consistently reported higher levels of ED cognitions and behaviors, with those in the EWL group also reporting higher levels of some ED cognitions and behaviors relative to the no-EWL group. Those in the EWL and driven exercise groups at age 14 also demonstrated a higher prospective likelihood of fasting (boys and girls) and purging (girls only) at age 16, relative to those in the no-EWL group at age 14. DISCUSSION: Results inform our understanding of EWL and driven exercise and the developmental timing of ED behaviors in adolescence and point toward the potential utility of targeted prevention for young people who report EWL.

Body composition in anorexia nervosa: Meta-analysis and meta-regression of cross-sectional and longitudinal studies.

OBJECTIVE: Clinically, anorexia nervosa (AN) presents with altered body composition. We quantified these alterations and evaluated their relationships with metabolites and hormones in patients with AN longitudinally. METHOD: In accordance with PRISMA guidelines, we conducted 94 meta-analyses on 62 samples published during 1996-2019, comparing up to 2,319 pretreatment, posttreatment, and weight-recovered female patients with AN with up to 1,879 controls. Primary outcomes were fat mass, fat-free mass, body fat percentage, and their regional distribution. Secondary outcomes were bone mineral density, metabolites, and hormones. Meta-regressions examined relationships among those measures and moderators. RESULTS: Pretreatment female patients with AN evidenced 50% lower fat mass (mean difference [MD]: -8.80 kg, 95% CI: -9.81, -7.79, Q = 1.01 × 10-63 ) and 4.98 kg (95% CI: -5.85, -4.12, Q = 1.99 × 10-28 ) lower fat-free mass, with fat mass preferentially stored in the trunk region during early weight restoration (4.2%, 95% CI: -2.1, -6.2, Q = 2.30 × 10-4 ). While the majority of traits returned to levels seen in healthy controls after weight restoration, fat-free mass (MD: -1.27 kg, 95% CI: -1.79, -0.75, Q = 5.49 × 10-6 ) and bone mineral density (MD: -0.10 kg, 95% CI: -0.18, -0.03, Q = 0.01) remained significantly altered. DISCUSSION: Body composition is markedly altered in AN, warranting research into these phenotypes as clinical risk or relapse predictors. Notably, the long-term altered levels of fat-free mass and bone mineral density suggest that these parameters should be investigated as potential AN trait markers. RESUMENOBJETIVO: Clínicamente, la anorexia nervosa (AN) se presenta con alteraciones en la composición corporal. Cuantificamos estas alteraciones y evaluamos longitudinalmente su relación con metabolitos y hormonas en pacientes con AN. MÉTODO: De acuerdo con las pautas PRISMA, realizamos 94 meta-análisis en 62 muestras publicadas entre 1996-2019, comparando hasta 2,319 pacientes mujeres en pre-tratamiento, post-tratamiento, y recuperadas en base al peso con hasta 1,879 controles. Las principales medidas fueron masa grasa, masa libre de grasa, porcentaje de grasa corporal y su distribución regional. Las medidas secundarias fueron densidad mineral ósea, metabolitos y hormonas. Las meta-regresiones examinaron las relaciones entre esas medidas y moderadores. RESULTADOS: Las pacientes femeninas con AN pre-tratamiento mostraron un 50% menos de masa grasa (MD: -8.80 kg, CI 95%: -9.81, -7.79, Q = 1.01 × 10-63 ) y 4.98 kg (CI 95%: -5.85, -4.12, Q = 1.99 × 10-28 ) menos de masa libre de grasa, con masa grasa preferentemente almacenada en la región del tronco durante la recuperación temprana del peso (4.2%, CI 95%: -2.1, -6.2, Q = 2.30 × 10-4 ). Aunque la mayoría de los rasgos regresaron a los niveles vistos en los controles sanos después de la restauración del peso, la masa libre de grasa (MD: -1.27 kg, CI 95%: -1.79, -0.75, Q = 5.49 × 10-6 ) y la densidad mineral ósea (MD: -0.10 kg, CI 95%: -0.18, -0.03, Q = 0.01) permanecieron significativamente alteradas. DISCUSIÓN: La composición corporal es marcadamente alterada en la AN, lo que garantiza la investigación en estos fenotipos como predictores de riesgo clínico o de recaída. Notablemente, la alteración a largo plazo de los niveles de masa libre de grasa y densidad mineral ósea sugieren que estos parámetros debe ser investigados como potenciales rasgos indicadores de AN.

Mechanisms of action during a dissonance-based intervention through 14-month follow-up: The roles of body shame and body surveillance.

Objectification theory posits that internalization of societal perspectives about the female body leads to increased body surveillance, which can result in body-related shame and subsequent eating disorder (ED) behaviors. Preliminary research indicates that these associations may be complex in nature. This study examined temporal relations among body surveillance, body shame, and eating disorder symptoms in the context of a dissonance-based body image intervention and through 14-month follow-up. College women (N=285) completed assessments at baseline, post-intervention, and at 8-week, 8-month, and 14-month follow-up. Cross-lag panel analyses revealed that changes in body surveillance significantly mediated the association between body shame and ED symptoms over time. Alternatively, body shame did not change over time and was not a significant mediator of associations between body surveillance and ED symptoms longitudinally. Results indicate that the ameliorative effects of dissonance-based interventions may be due to reductions in body surveillance, rather than decreased body shame.