Children and adolescents are not small adults: toward a better understanding of multimorbidity in younger populations.

Multimorbidity is of an increasing importance for the health of both children and adults but research has hitherto focused on adult multimorbidity. Hence, public awareness, practice, and policy lack vital information about multimorbidity in childhood and adolescence. We convened an international and interdisciplinary group of experts from six nations to identify key priorities supported by published evidence to strengthen research for children and adolescent with multimorbidity. Future research is encouraged (1) to develop a conceptual framework to capture unique aspects of child and adolescent multimorbidity-including definitions, characteristic patterns of conditions for different age groups, its dynamic nature through childhood and adolescence, and understanding of severity and trajectories for different clusters of multiple chronic conditions, (2) to define new indices to classify the presence of multimorbidity in children and adolescents, (3) to improve the availability and linkage of data across countries, (4) to synthesize evidence on the global phenomenon of multimorbidity in childhood and adolescence and health inequalities, and (5) to involve children and adolescents in research relevant to their health.