News Excerpt:

Researchers from the Centre for Cellular and Molecular Biology (CSIR-CCMB) and affiliated institutions have discovered that, in low- and middle-income countries (LMICs), environmental influences are far more important than heredity which regulates childhood height in European nations.

Key observations from the study:

• Human height is strongly influenced by fixed genetic and variable environmental factors.
• Authors of the study noted that the contribution of modifiable epigenetic factors is under-explored.
• Environmental factors:
  • These factors including socio-economic status, nutrition, and infection load are believed to influence childhood growth which plays a critical role in determining one’s height.
  • According to the World Health Organization, 2021 estimates - a significant fraction of stunted children live in low- and middle-income countries (LMICs), especially in South Asia and sub-Saharan Africa.
    • In these regions, undernutrition and related co-morbidities are more common than in high-income countries (HICs).
• Epigenetic processes such as DNA methylation and histone modifications can influence gene expression.
  • Methylation is a chemical modification of DNA molecules used by cells to regulate gene expression.
  • It can be influenced by environmental factors such as diet, drugs, stress, and exposure to chemicals and toxins.

• They found an association between methylation in the SOCS3 (Suppressor of cytokine signaling 3) gene and height in children from LMICs which was replicated in the HICs cohort but with a lower effect size.

Implications and Future Directions: 

• These findings have crucial implications for understanding the disparity in height variation between LMICs and HICs. 
• In HICs, where nutrition and healthcare are generally better, genetic factors play a more significant role in determining height. 
• However, in LMICs, with variable socio-economic factors and access to healthcare, environmental factors have a larger impact. 
• This study underscores the need to address environmental factors to improve the height and overall health of children in LMICs, paving the way for targeted public health interventions.