Study Links Body fat, Muscle Mass & Fitness to Mental Health in Preadolescent Children
CHICAGO – New research published august 2025 in JAMA Network Open reveals meaningful connections between body composition, physical fitness, adn mental health in children before adolescence. The study, led by braun, Khan, hillman, and Raine, found that higher levels of visceral adipose tissue (VAT) are associated with increased symptoms of both anxiety and depression, while greater lean mass and higher cardiovascular fitness appear to be protective factors.
The cross-sectional study examined data from a cohort of preadolescent children, utilizing assessments like the State-Trait Anxiety Inventory for Children (STAI-CH) and a measure of depressive symptoms (CDI). Researchers discovered a statistically significant association between higher body fat percentage (BF%) and increased anxiety symptoms, measured by STAIC-T (β = 0.15; 95% CI, 0.23 to 6.33; P =.04). Similarly, higher VAT levels were also linked to increased anxiety (β = 0.15; 95% CI, 0.04 to 1.82; P = .04).Conversely, higher lean mass was associated with lower anxiety scores (β = −0.16; 95% CI, −14.77 to −1.21; P =.02), and higher VOpeak (a measure of cardiovascular fitness) was also linked to reduced anxiety (β = −0.19; 95% CI, −0.28 to −0.04; P = .01).
These patterns extended to depressive symptoms. While BF% wasn’t substantially linked to depression, higher VAT was significantly correlated with increased depressive symptoms (β = 0.27; 95% CI, 0.34 to 1.11; P < .001). Again, greater lean mass (β = −0.16; 95% CI, −6.39 to −0.43; P = .03) and higher VOpeak (β = −0.16; 95% CI, −0.11 to −0.01; P = .03) were associated with fewer depressive symptoms. Notably, the commonly used metric of Body mass Index (BMI) showed no significant relationship to either anxiety or depression within this group, though trends aligned with expectations.This finding, the authors emphasize, highlights the limitations of relying solely on BMI and the importance of more detailed assessments of body composition. The study authors noted that "greater lean mass and higher fitness were associated with fewer anxiety and depression symptoms, while higher VAT was associated with increased symptoms of both." They hypothesize that VAT's influence on mood might potentially be linked to inflammatory processes and its impact on brain regions governing stress response. Lean mass and fitness, on the other hand, may offer protection through anti-inflammatory effects, enhanced neuroplasticity, and improved stress regulation. While acknowledging the cross-sectional design prevents establishing causality, the researchers suggest that monitoring body composition and fitness levels could aid in identifying children at increased risk for mental health challenges. They advocate for longitudinal studies to further investigate the underlying mechanisms and developmental pathways involved, and conclude that "integrating modifiable factors like fitness and body composition into routine pediatric assessments may help guide preventative care and early intervention to improve children's mental health outcomes."
