2011-2012 Grad

Lam

The effects of psychological stress, depressive symptoms, and cortisol on body mass and central adiposity in 10- to 12-year-old children

The percentage of children with elevated body mass and central adiposity has tripled in the U.S. over the past thirty years. While physical factors, such as decreased physical activity and poor nutrition, have been noted to influence elevated body mass and central adiposity in school-aged children, less is known about psychological factors, such as psychological stress and depressive symptoms, especially in 10-to12-year-old children.  Further, it has been suggested that cortisol, a biomarker of psychological stress, plays a role in the underlying mechanism that links psychological stress and depressive symptoms to increased body mass and central adiposity, but this has not been addressed.

The purpose of this study was to examine the influence of psychological stress and depressive symptoms on body mass and central adiposity in 10-, 11-, and 12-year-old children and included controlling for gender, ethnicity, puberty, and SES.  In addition, the principal researcher sought to determine the mediating role of cortisol in the relationships among psychological stress, depressive symptoms, body mass, and central adiposity. 

A convenience sample of 147 (84 girls, 63 boys; 67.3% White, 11.6% African American, 17.7% Hispanic, 2.0% Asian, and 1.4% More than one race) 10-, 11-, and 12-year-old children were enrolled from a rural southeastern school district.  More than half (51.7%) of the participants were overweight or obese.  A majority of the participants had cortisol levels within the normal range of 1.69 to12.81 nmol/l, while 8.3% had cortisol levels above the range.  Approximately, 15.6 % of boys had WC measures at or above the 90th percentile, while 19% of girls had WC measures at or above the 90th percentile.

After controlling for gender, puberty, ethnicity, and SES, the predictor variable depressive symptoms explained a significant amount of the variance in body mass and central adiposity.  The predictor variable psychological stress explained a significant amount of the variance in both body mass and central adiposity when the independent variable depressive symptoms was not included in the model.  A lack of statistically significant relationships between psychological stress and cortisol, and between depressive symptoms and cortisol precluded the need for additional testing of cortisol for mediation.


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