“…Of the 19 reviews, four included only randomised controlled trials (RCTs) or cluster RCTs, [23,46,54,58] and seven undertook pooled quantitative analyses [23,26,44,46,47,54,55]. Eight reviews included primary studies undertaken in children and adolescents only (between 1 and 18 years), [22,23,46,51,54,55,57,58] two were in adults (> 18 years) only, [50,56] nine included all ages, [26, 43-45, 47, 49, 52, 53] and one review did not specify ages included but gave the population as workers [48].…”