Adiposity, insulin resistance, cardiorespiratory fitness and bone health in Hispanic children

Authors: SHAWAR, REEM - Children'S Nutrition Research Center (CNRC); PUYAU, MAURICE - Children'S Nutrition Research Center (CNRC); SHYPAILO, ROMAN - Children'S Nutrition Research Center (CNRC); MUSAAD, SALMA - Children'S Nutrition Research Center (CNRC); BUTTE, NANCY - Children'S Nutrition Research Center (CNRC); BACHA, FIDA - Children'S Nutrition Research Center (CNRC)

Submitted to: Journal of Clinical Endocrinology and Metabolism
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2022
Publication Date: 6/6/2022
Citation: Shawar, R.S., Puyau, M., Shypailo, R., Musaad, S., Butte, N.F., Bacha, F. 2022. Adiposity, insulin resistance, cardiorespiratory fitness and bone health in Hispanic children. Journal of Clinical Endocrinology and Metabolism. https://doi.org/10.1210/clinem/dgac344.
DOI: https://doi.org/10.1210/clinem/dgac344

Interpretive Summary: Obesity appears to have a negative impact on pediatric bone health, and insulin resistance may mediate this relationship. It is unclear if cardiorespiratory fitness may have a protective effect on bone in obese children. Researchers in Houston, Texas examined data on a large number of Hispanic youth to evaluate the effect of insulin resistance and cardiorespiratory fitness on bone health. Our results showed that lean body mass is the major determinant of bone mineral content and bone mineral density in Hispanic youth, while body fat has a negative relationship to these measures of bone health. This suggests that greater cardiorespiratory fitness and higher lean mass may reduce the adverse effects of adiposity and insulin resistance on bone health in children. These findings support the importance of promoting an increase in physical activity to prevent the negative impact of obesity on bone health in children.

Technical Abstract: Childhood obesity disproportionately affects Hispanic youth. The skeletal system appears to be a target organ of the adverse effects of obesity. Yet, the relationship between adiposity and bone health in youth and the modulating factors are not well understood. To examine the relationship between adiposity, insulin resistance, cardiorespiratory fitness (CRF) and bone mass in Hispanic youth. Cross-sectional design from the Viva La Familia Study. Children’s Nutrition Research Center. A total of 951 Hispanic youth (50% male), 4 to 19 years of age. Bone mineral content (BMC) and density (BMD), lean mass, total body fat mass (FM), truncal FM were obtained using DXA. Fasting glucose and insulin were obtained and the homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. CRF was measured using a treadmill ramp protocol. We applied linear regression models and mediation analyses. Adiposity measures were negatively related to BMC and BMD after accounting for lean mass and sex. Insulin resistance negatively contributed whereas CRF positively contributed to the variance in BMC and BMD, more notably in the pubertal age group. In mediation analysis, HOMA-IR partially mediated the negative relationship of adiposity to BMC [standardized indirect effect (IE) = -.0382; 95% CI, -.0515 to -.0264) whereas the sequential indirect effect of HOMA-IR and CRF partially attenuated [IE= -.0026; 95% CI, -.0053 to -.0005] this relationship. Similar findings were seen with BMD as the primary outcome. Insulin resistance mediates the negative relationship between adiposity and bone mass whereas CRF may partially attenuate it.