Tracking of body adiposity indicators from childhood to adolescence: Mediation by BMI

<div><p>Our aim was to verify the tracking of body adiposity indicators from childhood to adolescence and analyze the mediation effects of BMI on the stability of body adiposity. Our sample was composed by 375 children (197 boys). The children were followed-up over 3 years. Body mass and stature were measured as anthropometric indicators. Body adiposity was estimated through the subcutaneous skinfold method, with measures of triceps (TRSF) and subscapular skinfolds (SSSF). Skinfolds were analyzed singly and agglutinated through the sum of skinfolds (∑SF). The sample was categorized into tertiles, and thereafter, the kappa coefficient and McNemar test were adopted to verify stability. For continuous measures, the Intra-Class Correlation coefficient (ICC) was used. Moreover, mediation analyzes were used according to Baron and Kenny with the Sobel test to verify mediation effects. The significance level adopted was 5%. Adiposity indicators increased during the 3 years of follow-up in both sexes (p<0.05). ICCs in all indicators of adiposity were between 0.84 and 0.94 for boys and 0.86 and 0.94 for girls, indicating high tracking. Moreover, 70% of subjects remained in the highest tertile of body adiposity. However, no differences were observed in tertile changes (p>0.05). BMI at the age of adiposity rebound partially mediated all indicators of adiposity from childhood (baseline) to adolescence (3 years later) in both sexes (p<0.001). Thus, moderate to high tracking of body adiposity indicators between childhood and adolescence was verified. Moreover, BMI at the age of adiposity rebound partially mediated the relationship between adiposity in childhood (baseline) and in adolescence (3 years of follow-up).</p></div

<i>Tracking</i> (%) of subjects that maintained in the same tertile or changed to a lower tertile (LT) or higher tertile (HT) of body adiposity indicators according to sex.

<p><i>Tracking</i> (%) of subjects that maintained in the same tertile or changed to a lower tertile (LT) or higher tertile (HT) of body adiposity indicators according to sex.</p

Characteristics of the sample, presented as means and standard deviation, with comparisons between baseline and after 3 years of follow-up.

<p>Characteristics of the sample, presented as means and standard deviation, with comparisons between baseline and after 3 years of follow-up.</p

Proportion of subjects that maintained or changed their tertiles of body adiposity during 3 years of follow-up.

<p>Note: TRSF, triceps skinfold; SSSF, subscapular skinfold; ∑SF, sum of skinfolds (TRSF + SSSF). * P < 0.001.</p

Mediation models by BMI at the age of adiposity rebound of the relationship between adiposity in childhood (baseline) and adiposity in adolescence (3 years follow-up) adjusted by chronological age and sex.

<p>Note. BMI, body mass index; TRSF, triceps skinfold; SSSF, subscapular skinfold; SF, skinfolds (TRSF + SSSF) *p < 0.05; **p ≤ 0.001.</p

Intra-class correlation coefficient (ICC) and confidence intervals (CI 95%) of body adiposity indicators between baseline and after 3 years of follow-up according to sex.

<p>Intra-class correlation coefficient (ICC) and confidence intervals (CI 95%) of body adiposity indicators between baseline and after 3 years of follow-up according to sex.</p