... manage and analyze the data.First, missing values were handled according to the guidelines given in the manual of the KIDSCREEN-52. The percentage of missing data was <10%. Second, anindependent ... data and drafted and revised the manuscript. JO, HH and MP supervisedexecution of the study and revised the manuscript. MAG designed and supervised execution of the study, interpreted the data and ... Amsterdam, The Netherlands.Authors’ contributionsCTH collected the data, analyzed and interpreted the data and drafted the manuscript. KF designed and supervised execution of the study, interpretedthe...