Objectively Measured Physical Activity and Its Association With Adiponectin and Other Novel Metabolic Markers

Abstract

<jats:p>OBJECTIVE—Recent evidence suggests that, in children, traditional markers of metabolic disturbance are related only weakly to physical activity. We therefore sought to establish the corresponding relationships with newer metabolic markers.</jats:p> <jats:p>RESEARCH DESIGN AND METHODS—This was a nonintervention longitudinal study of 213 healthy children recruited from 54 schools in Plymouth, U.K. MTI accelerometers were used to make objective 7-day recordings of physical activity at ages 5 ± 0.3 (mean ± SD), 6, 7, and 8 years. Overall physical activity was taken as the average of the four annual time points. The metabolic markers at 8 years were adiponectin, leptin, high-sensitivity C-reactive protein (hsCRP), and insulin resistance (homeostasis model assessment). Potential confounders included percent body fat measured by dual-energy X-ray absorptiometry and diet measured by food frequency questionnaire.</jats:p> <jats:p>RESULTS—Whereas physical activity did not correlate with insulin resistance (r = −0.01), leptin (r = +0.04), or hsCRP (r = +0.01) independently of percent body fat, it did correlate with adiponectin, but inversely (r = −0.18, P = 0.02). This unexpected inverse relationship was strongest among the less active children (physical activity &amp;lt; median: r = −0.30, P = 0.01) but negligible in the more active children (physical activity &amp;gt; median: r = +0.04, P = 0.76). Adiponectin was significantly higher (0.52 SD, P &amp;lt; 0.01) in the least active tertile compared with the other two tertiles. Insulin resistance, however, did not differ across the physical activity tertiles (P = 0.62).</jats:p> <jats:p>CONCLUSIONS—Adiponectin levels in children are highest among those who are least active, but their insulin resistance is no different. Adiponectin has a known insulin-sensitizing effect, and our findings are consistent with a selective effect at low levels of physical activity.</jats:p>