“…Of these, some focused only on children 17 , 23 , 28 , others examined mostly children and adolescents aged up to 12 years 2 , 12 , 31 whereas another study analyzed only adolescents 15 . Others studied patients from both age groups, aged up to 19-20 1 , 3 - 11 , 13 , 14 , 16 , 18 - 22 , 24 - 27 , 29 , 30 , 32 , 33 - 35 , and tested a smaller or greater number of substances than in this study: 17 substances for children under 5 years old 11 ; a pediatric series of 30 substances 23 , 24 , 25 ; 30 substances for children under 10 years old 12 ; and series of 10 substances. 30 Other studies have used standardized series for adults 1 , 2 , 5 - 11 , 13 - 16 , 19 - 22 , 25 , 27 , 28 , 31 , 33 - 35 , with variation in the number of substances tested.…”