Bad Genes or Genes Behaving Badly

Study Summary

A key factor in the determination of body composition over the lifecourse is fat accumulation during childhood. Periods of life associated with the greatest changes in organ development and growth, i.e. early childhood, have the most significant effect on body composition, energy balance, and metabolism. Early childhood (age 3 to 7 years) represents a critical transition for the basis of adaptability in body composition, due to the rapid growth and development that occurs. Plausibly the phenotype underlying obesity and related health risk may be determined by body composition during this critical period. Our previous research in children has consistently indicated that HA children accumulate greater amounts of fat, particularly in the intra-abdominal compartment, even at similar a BMI, and lower bone mineral content relative to EA children. The reason for these differences in body composition over the lifecourse is not clear. Racial/ethnic differences in risk factors for health, including 'thriftiness' in body fat accumulation are often evident before the age of 7, suggesting that the racial/ethnic differences in energy utilization and subsequent fat storage may be accounted for by genetic make-up, the environment (e.g. diet), or an interaction of the two. The physiologic or behavioral process(es) that cause(s) certain children to take a trajectory towards obesity while others accrue less fat is not known. However, the economic decision of fuel utilization is a physiologic trait enabling the body to choose between shuttling 'energy' towards accrual of a particular tissue (e.g. bone vs. fat) and this trait likely has a genetic component. This genetic component may be embedded in fat storage capacity evolved from gene by environment interactions that promote thrift, particularly conserved in some populations. Although genetic background plays a role, it not known whether there is a relationship between genetic background, known candidate genes or candidate pathways