A one-year school-based diet/exercise intervention improves non-traditional disease biomarkers in Mexican-American children

Abstract

School-based interventions are an effective way to treat childhood obesity. The purpose of the present study was to biologically validate an established school-based intervention designed to reduce standardised body mass index (zBMI) over a period of 12 months. This intervention focused on a subset of Mexican-American children who were participating in a larger clinical weight loss study. Plasma samples were analysed from self-identified Mexican-American children (12-14 years) who were randomised to either a school-based intervention (IN, n = 152) or self-help control (CN, n = 69). Treatment was 4 days week⁻¹ of exercise (45 min day⁻¹) and 1 day week⁻¹ of nutritional counselling for 6 months. Fasting (>8 h) blood samples were collected at baseline, 6 months (end of active intervention) and 12 months (6 months after the end of the active intervention). Plasma resistin, adiponectin and leptin concentration were measured using a multiplex assay. Separate linear mixed models and a P < 0.05 were used to test for significance. Significant group × time interactions were found for resistin (P < 0.0001), adiponectin (P = 0.001) and leptin (P = 0.013). For resistin, IN was 12% lower at 6 months than CN. Adiponectin concentration in IN was greater at 6 months (26%) and 12 months (8%) than CN. Leptin concentration was 22% lower for IN at 12 months than CN. We have previously reported that our school-based intervention reduced zBMI and now reported alterations in biologically relevant disease biomarkers. Some of the observed changes were only present at the end of the active intervention (resistin), while others persisted until 12 months (leptin and adiponectin). These changes underscore the effectiveness of our school-based intervention at not only improving zBMI but also at reducing disease risk.

Keywords: adiponectin; childhood obesity; leptin; resistin; weight loss.

Figure 1

Percent change in plasma resistin from baseline in Mexican‐American children who were either randomised to an intervention (n = 152; grey circles) or control (n = 69, black diamonds) group. Intervention subjects completed a 6‐month supervised intervention that consisted of 4 days week⁻¹ of exercise (45 min day⁻¹) and 1 day week⁻¹ of nutritional counselling. Compared with baseline, the control group increased by 10% and the intervention group decreased by 16%. Values represent the % change ± standard error of the mean. → indicates greater than intervention group (P < 0.05).

Figure 2

Percent change in plasma adiponectin from baseline in Mexican‐American children who were either randomised to an intervention (n = 152; grey circles) or control (n = 69, black diamonds) group. Intervention subjects completed a 6‐month supervised intervention that consisted of 4 days week⁻¹ of exercise (45 min day⁻¹) and 1 day week⁻¹ of nutritional counselling. Compared with baseline, at 6 months, the control group decreased by 80% and the intervention group decreased by 64%. Compared with baseline, at 12 months, the control group decreased by 50% and the intervention group decreased by 32%. Values % change ± standard error of the mean. *indicates greater than control group (P < 0.05).

Figure 3

Percent change in plasma leptin from baseline in Mexican‐American children who were either randomised to an intervention (n = 152; grey circles) or control (n = 69, black diamonds) group. Intervention subjects completed a 6‐month supervised intervention that consisted of 4 days week⁻¹ of exercise (45 min day⁻¹) and 1 day week⁻¹ of nutritional counselling. Compared with baseline, at 12 months, the control group increased by 100% and the intervention group increased by 78%. Values represent the % change ± standard error of the mean. → indicates greater than intervention group (P < 0.05).