The diabetes drug metformin has been used off-label to manage a variety of conditions in children and adolescents. This can result in maintenance, or small reductions, in body mass index (BMI), which is assumed to be a result of weight loss. But a new systematic review of ten randomised controlled trials suggests that in fact this may be a result of height increases in children.
In the study, published in JAMA Pediatrics (online, 28 September 2015)
, metformin decreased BMI. The five studies with the highest cumulative doses of metformin increased height by a mean of 1cm as well as reducing BMI compared with a control group.
The researchers at the University of Alberta, Canada, acknowledge that the studies have a number of limitations, and suggest that further research in younger participants should be carried out.
 Kuzik N, Myette-CÃ´tÃ© E, Carson V et al. Evaluating the effects of metformin use on height in children and adolescents: a meta-analysis of randomized clinical trials. JAMA Pediatrics 2015. doi:10.1001/jamapediatrics.2015.2186