To the Editor In the longitudinal study by Toseeb et al1 recently published in JAMA Pediatrics, the authors showed no association between objectively assessed physical activity (PA) and the development of depression symptoms in 736 adolescents across a 3-year period. These important findings are in apparent disagreement with previous interventional research relying mostly on short-term interventions with smaller cohorts and that use self-reported measures of PA.2 Notwithstanding the merit and methodological strengths of the study by Toseeb et al, we believe some clarifications are needed regarding a few potential confounding factors that were not controlled for.