INTRODUCTION:

Childhood obesity is a condition which involves in itself an oxidative stress and chronic inflammation that stimulates the production of corticosteroids and promotes the early onset of insulin resistance and diseases such as type 2 diabetes mellitus.

OBJECTIVE:

Assess ment of body composition in Costa Rican child population using deuterium dilution techniques and analysis its of relationship with the index of insulin resistance and morning serum cortisol levels.

RESULTS:

No statistically significant differences between groups of fat mass classification according to McCarthy was observed for variables morning serum cortisol and HOMA index of insulin resistance in the selected sample.

CONCLUSION:

In children between 6 and 9 years old the expected biochemical characteristics of the metabolic syndrome are not evident, given the short time exposure to oxidative stress of obesity, determined by measuring fat mass with an early method as isotopic dilution. Also, in early ages renal detoxification mechanisms of corticosteroids are sufficient to prevent elevated serum concentration and protect children from its long-term effects.