Li Z, et al. - In this longitudinal study, researchers studied the role of leptin as a mediator in the connection between body adiposity and persistent asthma. Utilizing data from the French prospective French Epidemiological Study on the Genetics and Environment of Asthma, a causal approach to mediation analysis was used to distinguish total impact from direct impact, as well as the indirect impact mediated by leptin. The study sample consisted of 331 participants with current asthma at baseline. Findings revealed that leptin partly (> 60%) mediated the link between high body adiposity and persistent asthma over time. Using a newly developed analytical approach, this investigation brought new insight into one mechanism through which obesity can affect the activity of asthma.