Objectives: Muscle-thin but adipose ('thin-fat') body composition of south Asian adults contributes to their high risk of type 2 diabetes. Studies in Pune, India showed that this phenotype is present at birth. We aimed to determine if south Indian babies have a 'thin-fat' phenotype and if this persists in childhood.
Design: Prospective cohort study.
Setting: Holdsworth Memorial Hospital, Mysore, India.
Subjects: Children (n = 663) whose mothers were recruited from the antenatal clinics.
Methods: Weight, length, head, mid-upper-arm, abdominal circumferences; triceps and subscapular skinfolds were measured at birth, one and four years, and compared with white Caucasian babies born in Southampton, UK (birth), and UK and Dutch growth standards (one and four years).
Results: Mysore babies were lighter (2983 g vs 3472 g; -1.10 SD, CI -1.16, -1.02) and smaller in all body measurements than UK neonates (P < 0.001). The deficit was greatest for mid-upper-arm (-1.07 SD), head (-0.89 SD) and abdominal circumferences (-0.73 SD), and least for length (-0.25 SD) and subscapular skinfold thickness (-0.19 SD). Predictors of skinfold thickness were maternal body mass index (P < 0.001) and socio-economic status (P = 0.05). At four years, subscapular skinfold thickness was larger than UK (+0.18 SD, CI +0.11, +0.25; P < 0.001) and Dutch standards (+0.61 SD, CI +0.51, +0.71; P < 0.001), despite all other body measurements remaining smaller. Predictors of 4-year skinfold thickness were neonatal skinfold thickness (P = 0.001) and maternal insulin concentrations (P = 0.05).
Conclusions: Mysore newborns have a 'thin-fat' phenotype. This may reflect the action of genes and/or the 'maternal environment'. The phenotype persists in childhood, and may be the forerunner of a diabetogenic adult phenotype.