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Direction of causality between body fat and insulin resistance in children--a longitudinal study (EarlyBird 51)
Joanne Hosking1, Brad S Metcalf, Alison N Jeffery
1Department of Endocrinology & Metabolism, Peninsula Medical School, Plymouth campus, UK.
Insights
Adiposity (body fat) primarily drives insulin resistance in children. In boys, this relationship is bidirectional long-term, while in girls, high insulin resistance may limit further fat gain.
Area of Science:
- Pediatric endocrinology
- Metabolic health research
- Childhood obesity studies
Background:
- Insulin resistance (IR) is a growing concern in pediatric populations.
- The causal relationship between adiposity and IR in children requires further elucidation.
- Understanding this bidirectional link is crucial for early intervention strategies.
Purpose of the Study:
- To determine the direction of causality between adiposity and insulin resistance in children.
- To analyze short-term and long-term associations in a pediatric cohort.
Main Methods:
- Longitudinal study of 238 children (aged 7-13 years).
- Annual measurements of body composition (DEXA) and insulin resistance (HOMA-2 IR).
- Statistical modeling to assess associations between adiposity and IR changes over time.
Main Results:
- Baseline adiposity significantly predicted short-term changes in insulin resistance.
- Long-term, adiposity showed a weaker association with IR changes.
- Baseline insulin resistance did not predict short-term adiposity changes; long-term associations varied by gender.
Conclusions:
- Adiposity is the primary driver of insulin resistance in children.
- In boys, a long-term bidirectional relationship exists between adiposity and IR.
- In girls, elevated IR may act as a protective mechanism against further fat gain, suggesting adaptive insulin desensitization.
Objective:
To investigate the direction of causality in the association between adiposity and insulin resistance in children.
Methods:
Body composition by DEXA, and insulin resistance by HOMA-2 IR were measured annually in 238 children aged from 7-13 years. Longitudinal modelling was used to establish whether baseline and/or trends in adiposity were associated with change in IR or whether, conversely, baseline and/or trends in IR were associated with change in adiposity.
Results:
Baseline adiposity was associated with change in IR in the short-term (p < 0.001) but less so in the long-term (p < 0.09) in both genders. Baseline IR was not associated with short-term change in adiposity in either gender (p > 0.42). In the long-term, baseline IR appeared to be positively associated with change in adiposity in boys (p = 0.02) but inversely associated with change in adiposity (the higher the baseline IR, the lower the gain in %fat) in girls (p < 0.001).
Conclusions:
The dominant direction of causality appears to be from adiposity to insulin resistance. In boys, adiposity appears to be both a cause and an effect of IR in the long term. In girls, however, higher insulin resistance appeared to limit further gain in body fat in the long term, an observation consistent with insulin desensitization as an adaptive response to weight gain.
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