Early childhood growth and weight gain are vital indicators of a healthy development and growth and can have a significant impact on body weight later in life. In particular, the difference between the highest (peak) and lowest (nadir) body weight during infancy can provide valuable insights into long-term health outcomes and help understand how the body regulates weight over time. A key period in this process is known as the adiposity rebound (AR), which is when a child’s body fat reaches its lowest point before starting to increase again. During AR, adiposity increases signifacntly during the first year and then decreases again. Then, a renewed rise (termed AR), occurs at around 5-6 years of age. The speed and intensity of such a rebound in BMI/weight can be an important predictor of future obesity risk, but it remains unclear why some children experience this rebound earlier or quicker than others, affecting observed weight gain velocities/patterns in later stages of life. We think that humans are exposed to two different genetically programmed adiposities: The first is their adiposity at age one, and the second is the adiposity trajectory that they follow for the rest of their life.

In this study, we aim to understand the genetic factors influencing such rebounding changes in body weight during early childhood. By using data from the ALSPAC cohort, which includes detailed measurements of body weight from birth through early childhood, we will apply advanced genetic analyses, such as genome wide association studies (GWAS) and polygenic risk scores (PRS) as well as mendelian randomization studies. Using genetic markers across the genome and associating these markers with the adiposity rebound can help predict an individual’s likelihood of developing certain traits or conditions, such as a predisposition to being overweight in both childhood or adulthood.

Our goal is to conduct a GWAS with this adiposity rebound to identify genetic factors that might explain the variations in body weight changes during infancy. By understanding the genetic basis of these differences, we hope to identify links between early childhood growth patterns and future health outcomes, such as obesity.

Ultimately, this research could help identify key biological pathways involved in weight gain and loss, improving our understanding of how weight changes in early childhood can influence long-term health and weight.