Objective

Exercise is a transdiagnostic clinical feature of eating disorders, but consensus is lacking as to what constitutes, and gives rise to, excessive exercise motivated by weight control. Using a longitudinal cohort study, we aimed to describe population-level prevalence rates of varying levels of weight-control exercise and examine gender and weight status (overweight or obesity; OVOB) as cross-sectional determinants of weight-control exercise in 14-15-year-old adolescents. We then evaluated the association of OVOB at 10-11 years with weight-control exercise at 14-15 years.

Methods

The sample comprised 6329 adolescents from the Longitudinal Study of Australian Children (LSAC). Weight and height were measured in early adolescence (aged 10-11) and in mid-adolescence (aged 14-15). Participants reported weight-control exercise using the Branched Eating Disorders Test at 14-15 years.

Results

In mid-adolescence, the estimated population prevalence for any weight-control exercise was 49 % (55 % in females). For girls, moderate levels of exercise were most prevalent, and low levels for boys. For all levels except for the very lowest, boys with (vs. without) OVOB history (10-11 years) had about twice the odds of endorsing every level of weight-control exercise. Patterns among girls were similar, though lower in magnitude (∼1.5 times).

Conclusions

For both girls and boys, across most exercise levels, rates of weight-control exercise were greatest for those with OVOB; for the highest exercise level, effects were strongest for boys with OVOB. To accurately identify at-risk adolescents, our results provide preliminary support for a fluid definition of excessive weight-control exercise, dependent on gender and weight status.

Objective

Despite known associations between eating disorders and obesity, little is known about the current prevalence of symptoms of eating disorders across the weight spectrum. This study therefore aimed to estimate the population prevalence of eating disorder symptoms in relation to weight status in adolescents.

Method

The sample comprised 3,270 participants (14-15 years; 52% boys) drawn from Wave 6 of the Longitudinal Study of Australian Children. Symptoms of anorexia nervosa (AN) and bulimia nervosa (BN) were assessed using self-report on the Branched Eating Disorder Test. This measure identifies clinically significant symptoms in the past 3 months according to the Diagnostic and Statistical Manual of Mental Disorders, fifth edition. Using study-derived cross-sectional population weights, the prevalence of each symptom was estimated for the total population and by sex and weight status.

Results

The estimated population prevalence was high (14.3-25.7%) for body image symptoms such as fear of weight gain and overvaluation of body weight but lower (0.5-3.7%) for behavioral symptoms such as binge eating and compensatory behaviors. Symptoms were more prevalent among adolescents with overweight or obesity. Although most symptoms tended to have higher prevalence among girls than boys, boys with obesity had higher prevalence of binge eating and excessive exercise than girls with obesity. The overall estimated population prevalence for AN and BN was 0.20% and 0.10%, respectively.

Discussion

The study highlights a need for clinicians to be cognizant of disordered eating behaviors regardless of weight status and has implications for both eating disorder and obesity prevention and intervention.

Policymakers must make management decisions despite incomplete knowledge and conflicting model projections. Little guidance exists for the rapid, representative, and unbiased collection of policy-relevant scientific input from independent modeling teams. Integrating approaches from decision analysis, expert judgment, and model aggregation, we convened multiple modeling teams to evaluate COVID-19 reopening strategies for a mid-sized United States county early in the pandemic. Projections from seventeen distinct models were inconsistent in magnitude but highly consistent in ranking interventions. The 6-mo-ahead aggregate projections were well in line with observed outbreaks in mid-sized US counties. The aggregate results showed that up to half the population could be infected with full workplace reopening, while workplace restrictions reduced median cumulative infections by 82%. Rankings of interventions were consistent across public health objectives, but there was a strong trade-off between public health outcomes and duration of workplace closures, and no win-win intermediate reopening strategies were identified. Between-model variation was high; the aggregate results thus provide valuable risk quantification for decision making. This approach can be applied to the evaluation of management interventions in any setting where models are used to inform decision making. This case study demonstrated the utility of our approach and was one of several multimodel efforts that laid the groundwork for the COVID-19 Scenario Modeling Hub, which has provided multiple rounds of real-time scenario projections for situational awareness and decision making to the Centers for Disease Control and Prevention since December 2020.