Associations of fat mass and fat-free mass accretion in infancy with body composition and cardiometabolic risk markers at 5 years: The Ethiopian iABC birth cohort study

Abstract

Background Accelerated growth in early childhood is an established risk factor for later obesity and cardiometabolic disease, but the relative importance of fat mass (FM) and fat-free mass (FFM) accretion is not well understood. We aimed to study how FM and FFM at birth and their accretion during infancy were associated with body composition and cardiometabolic risk markers at 5 years. Methods and findings Healthy children born at term were enrolled in the Infant Anthropometry and Body Composition (iABC) birth cohort between December 2008 and October 2012 at Jimma University Specialized Hospital in the city of Jimma, Ethiopia. FM and FFM were assessed using air displacement plethysmography a median of 6 times between birth and 6 months of age. In 507 children, we estimated individual FM and FFM at birth and their accretion over 0–3 and 3–6 months of age using linear-spline mixed-effects modelling. We analysed associations of FM and FFM at birth and their accretion in infancy with height, waist circumference, FM, FFM, and cardiometabolic risk markers at 5 years using multiple linear regression analysis. A total of 340 children were studied at the 5-year follow-up (mean age: 60.0 months; girls: 50.3%; mean wealth index: 45.5 out of 100; breastfeeding status at 4.5 to 6 months post-partum: 12.5% exclusive, 21.4% almost exclusive, 60.6% predominant, 5.5% partial/none). Higher FM accretion in infancy was associated with higher FM and waist circumference at 5 years. For instance, 100-g/month higher FM accretion in the periods 0–3 and 3–6 months was associated with 339 g (95% CI: 243–435 g, p < 0.001) and 367 g (95% CI: 250–484 g, p < 0.001) greater FM at 5 years, respectively. Higher FM at birth and FM accretion from 0 to 3 months were associated with higher FFM and cholesterol concentrations at 5 years. Associations for cholesterol were strongest for low-density lipoprotein (LDL)–cholesterol, and remained significant after adjusting for current FM. A 100-g higher FM at birth and 100-g/month higher FM accretion from 0 to 3 months were associated with 0.16 mmol/l (95% CI: 0.05–0.26 mmol/l, p = 0.005) and 0.06 mmol/l (95% CI: 0.01–0.12 mmol/l, p = 0.016) higher LDL-cholesterol at 5 years, respectively. Higher FFM at birth and FFM accretion in infancy were associated with higher FM, FFM, waist circumference, and height at 5 years. For instance, 100-g/month higher FFM accretion in the periods 0–3 and 3–6 months was associated with 1,002 g (95% CI: 815–1,189 g, p < 0.001) and 624 g (95% CI: 419–829 g, p < 0.001) greater FFM at 5 years, respectively. We found no associations of FM and FFM growth with any of the other studied cardiometabolic markers including glucose, HbA1c, insulin, C-peptide, HOMA-IR, triglycerides, and blood pressure. Non-attendance at the 5-year follow-up visit was the main limitation of this study...

WHO Child Growth Standards in context: The Baby–bod Project - Observational study in Tasmania

“…Although the exact mechanisms are yet to be elucidated, it is possible that significant metabolic changes associated with different body composition accrual patterns may potentially manifest as metabolic diseases in childhood or in adulthood. 15 Changes in body composition in early life are affected by a range of factors, including postpartum nutritional conditions, maternal characteristics including body weight, prepregnancy BMI and the intrauterine environment. 16 17 More specifically, existing evidence suggests that infant FM is particularly reflective of the intrauterine environment and energy supply in the last trimester, whereas FFM is largely determined via heredity.…”

Birth Size and Rapid Infant Weight Gain—Where Does the Obesity Risk Lie?

“…Further, although the key factor linking body size to morbidity and mortality is adipose tissue distribution and function, like body weight and BMI, percentage body fat is merely a surrogate overall measure of body fat. In addition to understanding the amount of adiposity an individual may have relative to their body size, research has implicated the composition of body fat (eg, brown vs white fat), 25,26 its distribution (eg, central vs peripheral), 26,27 the rate of its accretion, 28,29 and various biomarkers 30,31 as indices of adipose tissue function. Exploring differences in these factors may provide more information regarding adipose tissue function than investigating body size and its evolution in insolation.…”

Outcomes that explain excess of body fat mass in preschoolers: a cross-sectional exploratory study

“…The body mass index (BMI) and the FM are important determinants of metabolic health at the population level 9 . Despite the recognized use of BMI for associations with health outcomes 10 , the greatest accumulation of FM in early childhood has been associated with increased body weight, increased waisthip circumference 11 contributing to the later risk of cardiometabolic disease 12 . Studies investigating obesity in children used different methods to assess the amount of body fat mass, such as BMI 13 , waisthip circumference 14 , FM measured by bioelectrical impedance 15 or Dual Energy X-ray Absorptiometry -DEXA 16 .…”

“…The measurement of FM using the gold standard method, e.g. DEXA, is considered a reference 12,9 , since evidence indicates that FM gain in early childhood predicts increased levels of blood biomarkers related to cholesterol metabolism 11 .…”