Low-Energy Availability Indicators Among Female Adolescents After Concussion: A Comparison With Uninjured Controls.

Background: After concussion, metabolic disruption causes a mismatch between the brain's energy demand and the body's ability to deliver energy to the brain. Physical activity (ie, energy expenditure) is recommended after concussion to facilitate recovery. Low-energy availability (LEA) is defined as inadequate energy available to support physiologic function after accounting for exercise energy expenditure and may influence concussion symptoms or disrupt/prolong recovery.

Purpose/hypothesis: The purpose was (1) to investigate LEA indicators (LEA-I) among female adolescents with and without recent concussion and (2) to examine the relationship between LEA-I and concussion symptom severity. It was hypothesized that (1) participants with concussion would have higher LEA-I than controls and (2) LEA-I and concussion symptom severity would be moderately correlated.

Study design: Cross-sectional study; Level of evidence, 3.

Methods: Two groups of female adolescents ages 13 to 18 years completed the Low Energy Availability in Females Questionnaire (LEAF-Q): uninjured controls and adolescents within 21 days of concussion. The LEAF-Q evaluates gastrointestinal symptoms, menstrual function, and injury frequency (range, 0-25). LEA-I was defined as scores ≥8, indicative of high LEA risk. Participants with concussion rated symptoms using the Post-concussion Symptom Inventory (PCSI; range, 0-120), with higher scores indicating more severe symptoms. We used independent samples t tests and calculated effect sizes to examine LEAF-Q between-group differences and linear regression for a multivariable comparison. For the concussion group, the correlation between LEAF-Q and PCSI scores was examined via Pearson r coefficients.

Results: We enrolled 117 female adolescents: 88 controls (mean ± SD age, 15.9 ± 1.5 years) and 29 with concussion (age, 15.5 ± 1.4 years). Upon univariable analysis, the concussion group reported significantly higher LEAF-Q scores than controls (9.1 ± 4.0 vs 6.0 ± 3.7; P < .001; Cohen d = 0.81). After adjusting for age and body mass index, LEAF-Q scores were 3.23 points higher on average for the concussion group as compared with controls (β = 3.23; 95% CI, 1.49-4.96; P < .001). For the concussion group, there was a small and insignificant correlation between LEAF-Q and PCSI scores (r = -0.06, P = .74).

Conclusion: Female adolescents after concussion had LEAF-Q scores indicative of high LEA risk, while controls did not. The lack of correlation between LEAF-Q and PCSI scores suggests that LEA-I is not associated with concussion symptoms.