An Intermediary Role for Insulin Resistance in the Adipose-Bone Mass Relationship in Adolescents

According to study results published in The Journal of Clinical Endocrinology & Metabolism, insulin resistance may play an intermediary role in the relationship between adiposity and lumbar spine bone mass in adolescents.

To determine whether insulin resistance might be an intermediary in the relationship between fat mass and bone mass, researchers conducted a cross-sectional secondary analysis of baseline data for 240 participants age 7 to 15 who were measured for bone mineral content, areal bone mineral density, lean mass and fat mass, and waist circumference. The researchers also calculated insulin and glucose levels for each participant, as well as homeostasis model assessment of insulin resistance.

Adjusting for race, sex, sexual maturation, and height, fat mass (r =.45; P <.001) and waist circumference (r =.47; P <.001) were found to be positively associated with the homeostasis model assessment of insulin resistance. In contrast, controlling for the same covariates as well as lean mass, the researchers reported that fat mass, waist circumference, and homeostasis model assessment of insulin resistance were all negatively associated with lumbar spine bone mineral content and total body areal bone mineral density (P <.05 for all).

In addition, the researchers found fat mass to be a positive predictor of homeostasis model assessment of insulin resistance and homeostasis model assessment of insulin resistance to be a negative predictor of lumbar spin bone mineral content (P <.01 for both). Even after controlling for homeostasis model assessment of insulin resistance, waist circumference remained negatively associated with lumbar spine bone mineral content. A negative test for indirect effect confirmed this finding.

The researchers reported study limitations included the inability to infer causality due to its cross-sectional design and a lack of data pertaining to participants’ bone microarchitecture.

“Our results suggest that insulin resistance is an intermediary in the link between adiposity and lumbar spine bone mass in children,” the researchers said, “supporting earlier findings involving insulin resistance in the connection between adolescent obesity and trabecular bone.”

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Reference

Kindler JM, Lobene AJ, Vogel KA, et al. Adiposity, insulin resistance, and bone mass in children and adolescents [published online October 11, 2018]. J Clin Endocrin Metab. doi:10.1210/jc.2018-00353