Tracking body fat distribution during growth: using measurements at two occasions vs one

Boys but Not Girls Exposed to Maternal Gestational Diabetes Mellitus Have Unfavorable Fat Distribution

BACKGROUND

Maternal gestational diabetes mellitus (GDM) and overweight are associated with an increased risk of obesity and the metabolic syndrome in the adult offspring. We studied the influence of maternal GDM on prepubertal children's body composition and bone mineral biochemistry.

METHODS

A total of 134 prepubertal Caucasian children (age range 4.4-9.7 years) were studied in a controlled cross-sectional study. Seventy-six children had been exposed to maternal GDM and 58 children born after a normal pregnancy served as controls. The outcome variables were body fat %, android fat %, gynoid fat %, android/gynoid fat ratio, bone mineral density (BMD), bone mineral content (BMC), muscle mass, lean mass (LM) and serum 25-hydroxyvitamin D, ionized calcium, phosphate, and alkaline phosphatase concentrations.

RESULTS

There were no differences in body fat %, android fat %, BMD, BMC, muscle mass, or LM between the study groups. Gynoid fat % was higher in the GDM than control children (p = 0.03). Android fat %, gynoid fat %, and android/gynoid fat ratio were higher in the GDM boys than control boys (p = 0.046, 0.037, and 0.038) respectively, but no differences were found between the GDM and control girls.

CONCLUSIONS

Boys exposed to maternal GDM presented with more unfavorable fat distribution than their controls, whereas no difference was found between the girls. Otherwise, the differences in body composition were minimal between prepubertal GDM and control children.

Factors associated with tracking of BMI: a meta-regression analysis on BMI tracking

Stable tracking of body composition is a prerequisite for the long-term effect of preventive measures against obesity and its harmful effects. As BMI tracking estimates reported by individual studies vary considerably, we performed a meta-regression analysis to provide a summary estimate and to assess determinants of BMI tracking. Using the Medline and EMBASE databases, a systematic review was conducted to identify publications reporting correlation coefficients as tracking estimates between BMI at baseline and follow-up measurements and the time interval between these measurements. Additional information recorded included age at baseline measurement, gender, and origin of the studied population. Based on the extracted data, a meta-regression analysis was performed using mixed effects models to account for multiple measurements of the same cohorts. Data on 55,072 individuals (797,094 person-years) extracted from 48 publications with follow-up times between 0.5 and 44 years entered the analysis. The overall estimates for the 1-year tracking correlation coefficient were strong (r = 0.78-0.86 depending on age at baseline measurement) and gradually decreasing over time (0.67-0.78 after 10 years, and 0.27-0.47 after 30 years). Study origin classified by continent was another significant predictor of BMI tracking whereas gender was not. In conclusion, this meta-regression analysis showed a high degree of BMI tracking across all age groups investigated and independent of BMI. Successful prevention in weight control is likely to have long term effects at any age, thereby being beneficial with respect to the associated risks of over- and underweight.

Development and tracking of central patterns of subcutaneous fat of rural South African youth: Ellisras longitudinal study

Background

Individuals grow and accumulate central patterns of body fat into the diseases they will suffer from as older adults. The need to elicit the development and tracking of central patterns of body fat from younger age into adolescent remains to be explored.

Method

Skinfolds measurements were done according to the standard procedures in the Ellisras Longitudinal Growth and Health Study. In total, 2,225 children--550 preschool and 1,675 primary school--aged 3-10 years (birth cohorts 1993 to 1986) were enrolled at baseline in 1996 and followed through out the eight-year periodic surveys. In 2003, 1,771 children--489 preschool and 1,282 primary school--were still in the study.

Results

The development of triceps, biceps, suprailiac and suscapular skinfolds of Ellisras girls were significantly higher (p < 0.001 to 0.05) compared to boys over time. The tracking coefficient between the initial measurements and the subsequent measurements was higher for skinfolds (r about 0.63) than for skinfold ratios (r about 0.43). Longitudinal tracking coefficient measuring the association between the initial measurements and all the follow up measurements simultaneously was about 0.57.

Conclusion

The accumulation of central patterns of body fat of Ellisras children starts in childhood and adolescence spurt with Ellisras girls acquiring more than boys over time. High significant tracking of skinfold thickness while the skinfold ratios show low and insignificant tracking over time. The magnitude of central patterns of body fat accumulation over time requires further investigation to clarify their association with risk factors for cardiovascular diseases.

Percentiles of body composition from bioelectrical impedance and body measurements in U.S. adolescents 8-17 years old: Project HeartBeat!

Reference percentiles (5th, 10th, 50th, 85th, 90th, and 95th) of black and nonblack children ages 8-17 years from Project HeartBeat! (n = 678) are presented for body mass index (BMI), percent body fat (PBF), fat-free mass (FFM), and fat mass (FM) derived from bioelectrical impedance. Project HeartBeat! is a mixed longitudinal study in which three cohorts of children (seen initially at age 8, 11, or 14 years) were followed for 4 years and measured thrice-yearly from 1991 through 1995. Weight, height, and BMI of Project HeartBeat! children are similar in central tendency and variability to those of nationally representative samples for nonblack children but not black children, for whom there is an excess of children at or above the 95th percentile for weight and BMI. Values of PBF above which cardiovascular risk variables increase (as suggested in the literature) are located at the 85th percentile of the Project HeartBeat! distributions. This percentile of PBF may be tentatively considered as a cutoff point with epidemiological significance for children.

Obesity in a cohort of black Jamaican children as estimated by BMI and other indices of adiposity

OBJECTIVE

To examine the relationships of body mass index (BMI) to obesity indices derived from anthropometry and to determine tracking of overweight between late childhood and early adolescence, in a cohort of children with mixed nutritional history. We also compared identification of overweight children using The International Obesity Task Force (IOTF) BMI cut-off points with skinfolds.

DESIGN

Prospective study.

SETTING

Kingston, Jamaica.

SUBJECTS

A total of 306 children examined at 7-8 y and at 11-12 y.

MEASUREMENTS

Triceps (TSF) and subscapular skinfolds (SSF), height and weight were measured. The sum of the skinfolds (sum SF), BMI, percentage body fat (%fat) and fat mass (FM) were calculated. Pubertal stage was assessed at 11-12 y.

RESULTS

Overweight increased from 3.5 to 9.5% over the follow-up period. BMI was better correlated with the other indices of adiposity in girls and in the older age group. BMI tracking over follow up was high. In regression analysis BMI explained 52 and 61% of the variance in FM in boys and girls at 7-8 y. This increased to 69% in both sexes at 11-12 y. Using the IOTF cut-off points BMI had low sensitivity to identify children >85th percentile of the NHANES references for SSF. The sensitivity for those assessed by TSF and sum SF was higher, but between 14 and 30% of the children were misclassified. The specificity of BMI was high.

CONCLUSIONS

Adiposity increased over follow-up. Although the cohort remained relatively lean BMI rank among the fattest children was maintained. Girls were fatter than boys, reflecting adult obesity patterns. Children identified as overweight by the IOTF BMI cut-off points are likely to have high body fatness. However the BMI cut-off points may not identify many children with high body fatness.