Do cardiometabolic risk factors mediate the relationship between body composition and bone mineral content in South Indian children aged 5 to 16 years?

BACKGROUND/OBJECTIVE: The complex interplay between adiposity, bone health and cardiometabolic risk (CMR) factors is unclear in Indian children. We aimed to investigate the mediating role of number of CMR factors on the relationship between fat % and bone mineral content (BMC) % in South Indian children aged 5-16 years. SUBJECTS AND METHODS: Healthy children (n = 317), from India, underwent anthropometric, blood biochemistry, blood pressure, along with body composition and BMC assessments using Dual-energy X-ray absorptiometry. Based on the number of CMR factors, children were categorised into three groups: 0, 1 and ≥ 2. Analysis of variance was used to compare the parameters between the CMR groups and mediation analysis was performed to examine if the number of CMR factors mediated the relationship between fat % and BMC %. RESULTS: The prevalence of 0, 1 and ≥ 2 CMR factors was 42.3%, 33.9% and 23.9% respectively; mean BMC % was lowest in ≥ 2 CMR group. In the whole group, BMC % had significant negative correlation with fat % (r = -0.68, p < 0.0001) and positive correlation with lean % (r = 0.64, p < 0.0001). Adjusted for age and sex, results suggested significant mediating effect of number of CMR factors on the relationship between fat % and BMC % (Average Causal Mediation Effects =-0.002, bootstrapped 95% CI: -0.0039, -0.0001, p < 0.01), but losing significance when adjusted for co-variates. CONCLUSION: Number of CMR factors mediates the relationship between fat % and BMC % in Indian children. Further studies are needed to confirm these findings, understand mechanisms and plan appropriate strategies.

Comparison of growth patterns in the first year of life between term small for gestational age and appropriate for gestational age South Indian infants.

BACKGROUND: Early life growth trajectories of Indian small for gestational age (SGA) infants are sparse. This study aimed to compare longitudinal growth in appropriate for gestational age (AGA) and SGA infants during their first year of life. METHODS: Apparently healthy term infants (52 SGA, 154 AGA) were recruited at birth and followed up till 1 year. Parental, sociodemographic characteristics and feeding patterns were recorded. Anthropometric measurements were assessed at birth, 3, 6, 9 and 12 months of age; Z scores and growth velocity at 3-month intervals were computed. Longitudinal measurements were compared between the two groups, using the two-way Friedmans test. Median regression with mixed effects was used to adjust covariates; p value <0.05 was considered statistically significant. RESULT: AGA infants had significantly higher median weight (kg) (2.87 (2.67, 3.04) vs 2.39 (2.25, 2.54)) at birth, (7.08 (6.50, 7.54) vs 6.49 (6.13, 6.78)) at 6 months, (8.64 (7.92, 9.14) vs 7.90 (7.36, 8.54)) at 12 months, median length (cm) ((48.10 (47.20, 49.30) vs 46.75 (45.43, 47.50)) at birth, (65.50 (64.23, 66.98) vs 63.33 (62.26, 65.28)) at 6 months, (73.30 (71.58, 74.66) vs 71.55 (70.00, 73.30)) at 12 months. SGA infants had comparable weight velocity at all intervals except 9-12 months (6.62 (6.45, 6.79) vs (6.70 (6.51, 6.85)), being significantly higher than AGA infants. Differences in skinfold thicknesses between groups were observed only at birth. Exclusivity of breast feeding was significantly higher at 3 months in AGA, compared to SGA infants (80.9% vs 57.8%). Length velocity was comparable at all ages between groups. Sexual dimorphism was observed in the growth velocities of both groups. CONCLUSION: SGA infants grew in parallel to AGA infants, having significantly lower anthropometric measurements at all time points. However, growth velocities were similar; SGA infants had significantly higher weight velocity from 9 to 12 months. Longitudinal studies beyond 1 year of age, using body composition are needed to determine the quality of growth in Indian infants.

Body Composition Percentiles in Urban South Indian Children and Adolescents.

OBJECTIVE: This study aimed to generate age- and sex-specific percentiles for body composition indices in children and to assess the variability in these indices, in relation to BMI. METHODS: Anthropometry and body fat were measured with the BOD POD (Cosmed; Rome, Italy) in 9,702 children from Bangalore, India. Smoothed percentile curves using the lambda-mu-sigma method were obtained for BMI, fat-free mass index (FFMI), fat mass index (FMI), and body fat percentage (% BF). RESULTS: Percentile curves for % BF and FMI in boys increased from 6 to 12 years and declined from 13 years on, while in girls, it increased until 15 years. The FFMI percentile curves increased with age in both sexes. The mean FMI declined from 12 years on in boys, corresponding to a large increase in FFMI from that age, while in girls, both FMI and FFMI continued to increase. The 75th percentile of % BF and FMI had greater sensitivity to identify children with obesity. CONCLUSIONS: This study developed smoothed percentile curves for body composition in Indian children and suggests FMI and FFMI as good indicators of growth in children.