Tracking of weight status and body fatness in Italian children

Longitudinal associations of movement behaviours with body composition and physical fitness from 4 to 9 years of age: structural equation and mediation analysis with compositional data

BACKGROUND

The associations of movement behaviours (physical activity [PA], sedentary behaviour [SB], and sleep) with body composition and physical fitness from pre-school to childhood, as well as the direction of the associations, could provide important information for healthy lifestyle promotion in children. This study investigated the longitudinal and bidirectional associations of movement behaviours with body composition and physical fitness measured at 4 and 9 years of age.

METHODS

This longitudinal study included baseline (n = 315, 4.5 [SD = 0.1] years) and follow-up data (n = 231, 9.6 [SD = 0.1] years) from the MINISTOP study. Movement behaviours were measured for 7 days using wrist-worn accelerometers, body composition with air-displacement plethysmography, and physical fitness with the ALPHA health-related fitness test battery. Cross-lagged panel models and mediation analyses were performed in combination with compositional data analysis.

RESULTS

We did not observe direct associations of the movement behaviours at 4 years with either body composition or physical fitness at 9 years (all P > 0.05). However, fat mass index at 4 years was negatively associated with vigorous PA (VPA), relative to remaining behaviours (VPA, β = - 0.22, P = 0.002) and light PA (LPA), relative to SB and sleep (β = - 0.19, P = 0.016) at 9 years. VPA (relative to remaining), moderate PA (MPA) (relative to LPA, SB, and sleep), and SB (relative to sleep) tracked from 4 to 9 years (all β ≥ 0.17, all P < 0.002), and these behaviours shared variance with fat mass index (all|β| ≥ 0.19, all P < 0.019), and aerobic, motor, and muscular fitness (all|β| ≥ 0.19, all P < 0.014) at 9 years. Mediation analysis suggested that the tracking of VPA (relative to remaining behaviours) from 4 to 9 years was negatively associated with fat mass index (β ≥ - 0.45, P = 0.012), and positively with aerobic fitness at 9 years (β ≥ 1.64, P = 0.016).

CONCLUSION

PA and SB tracked from the pre-school years into childhood. Fat mass index at 4 years of age was negatively associated with VPA (relative to remaining behaviours) and LPA (relative to SB and sleep) at 9 years of age. The tracking of VPA was associated with lower fat mass index and higher aerobic fitness at 9 years of age. These findings suggest that higher levels of VPA in pre-school age, if maintained throughout childhood, may support the development of healthy body composition and aerobic fitness levels in later childhood.

TRACKING OF NUTRITIONAL STATUS BETWEEN CHILDHOOD AND ADOLESCENCE IN SCHOOLCHILDREN

ABSTRACT Introduction: In view of the growing prevalence of childhood excess weight and obesity In Brazil In recent decades, it is necessary to observe how this phenomenon occurs in the period of transition to adolescence. Objective: To verify the tracking of excess weight between childhood and adolescence in schoolchildren of both sexes. Methods: The study has a longitudinal design and the data used are part of a prospective study carried out from 2002 to 2005. Participants included 397 schoolchildren of both sexes (211 boys and 186 girls). The nutritional status was determined by the body mass index, and the participants were divided into the following groups: Normal Weight to Normal Weight, Normal Weight to Excess Weight, Excess Weight to Excess Weight, Excess Weight to Normal Weight. The tracking was analyzed using the intraclass correlation coefficient (ICC) and Kappa (k) index. Results: A significant difference (P <0.05) was observed between all variables (age and anthropometric indicators) between 2002 and 2005 for boys and girls. The ICC indicated tracking classified as high (ICC = 0.87) for the BMI values, and the tracking percentage showed that 87% of the subjects remained in the same category of normal weight and excess weight. The values of k = 0.68 show good tracking (P <0.001), indicating a strong maintenance of the subjects in the normal and excess weight categories. Conclusion: The tracking percentage was high, indicating that both boys and girls maintained the classification of excess weight during the period analyzed. Level of Evidence II; Lesser quality prospective study (eg, patients enrolled at different points in their disease or <80% followup).

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

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).

Associations of Infant Subcutaneous Fat Mass with Total and Abdominal Fat Mass at School-Age: The Generation R Study

BACKGROUND

Skinfold thickness enables the measurement of overall and regional subcutaneous fatness in infancy and may be associated with total and abdominal body fat in later childhood. We examined the associations of subcutaneous fat in infancy with total and abdominal fat at school-age.

METHODS

In a population-based prospective cohort study among 821 children, we calculated total subcutaneous fat (sum of biceps, triceps, suprailiacal, and subscapular skinfold thicknesses) and central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thicknesses/total subcutaneous fat) at 1.5 and 24 months. At 6 years, we measured fat mass index (total fat/height(3) ), central-to-total fat ratio (trunk fat/total fat), and android-to-gynoid fat ratio (android fat/gynoid fat) by dual-energy X-ray absorptiometry and preperitoneal fat mass area by abdominal ultrasound.

RESULTS

Central-to-total subcutaneous fat ratio at 1.5 months was positively associated with fat mass index and central-to-total fat ratio at 6 years, whereas both total and central-to-total subcutaneous fat ratio at 24 months were positively associated with all childhood adiposity measures. A 1-standard-deviation scores higher total subcutaneous fat at 24 months was associated with an increased risk of childhood overweight (odds ratio 1.70, 95% confidence interval 1.36, 2.12). These associations were weaker than those for body mass index and stronger among girls than boys.

CONCLUSIONS

Subcutaneous fat in infancy is positively associated with total and abdominal fat at school-age. Our results also suggest that skinfold thicknesses add little value to estimate later body fat, as compared with body mass index.