Metformin May Increase Height in Children, Adolescents

Pam Harrison

September 29, 2015

Greater cumulative exposure to metformin may increase height by a mean of approximately 1 cm in children and adolescents receiving metformin compared with peers who do not receive the drug, new research suggests.

The study was published online September 28 in JAMA Pediatrics.

Nicholas Kuzik, BSc, from the University of Alberta, Edmonton, Canada, and colleagues found that in a stratified analysis according to the cumulative dose of metformin children and adolescents had received, there was a greater increase in height among those who were treated in five studies in which the largest cumulative doses of metformin were reported, but not in another five studies in which the lowest doses of metformin were provided compared with nonmetformin controls.

"To our knowledge, this is the first meta-analysis to suggest that treatment with metformin may increase height in children and adolescents compared with a control group, particularly when a combination of large doses and longer treatment duration is used," the authors write. "It is possible that longer treatment periods or treatments concentrated at times of greater growth may lead to even greater height changes."

Some 10 studies with a total of 562 participants were included in the meta-analysis. The mean age of participants across all studies ranged from 7.9 to 16.1 years, although there was a high degree of variability in age, the authors observe. Duration of treatment was anywhere from 3 to 48 months.

"Overall, height changes were not significantly different between the metformin and control groups," the authors observe. Nor did treatment with metformin affect weight overall.

However, when studies were divided into subgroups based on higher vs lower cumulative metformin doses, the five studies in which children and adolescents were exposed to greater amounts of metformin demonstrated that treatment was associated with a decrease in body mass index at a weighted mean difference of −1.3 (95% confidence interval, −2.1 to −0.4) and an increase in height at a weighted mean difference of 1.0 cm (95%CI, 0.0 - 2.0 cm) compared with control groups, although it had no significant effect on weight.

In contrast, there were no changes in body mass index, height, or weight in the other five studies in which children and adolescents were exposed to lower cumulative doses of metformin compared with controls.

As the authors note, the approximately 1-cm greater growth seen among children and adolescents enrolled in the five studies in which larger cumulative metformin doses were given may seem small, but "the findings may still be clinically meaningful," they write.

As they point out, subgroups of participants in these studies may have already experienced epiphyseal growth plate closure and would be unlikely to have additional growth from any treatment effect provided by metformin.

"Therefore, it may be speculated that metformin administration during puberty could enhance or prolong the normally occurring, puberty-induced height change," the authors speculate, adding that longer studies in pubertal participants may reveal a much larger increase in height with metformin use than the overall approximate 1-cm increase suggested by the current meta-analysis.

The authors have disclosed no relevant financial relationships.

JAMA Pediatr. Published online September 28, 2015. Abstract


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.