Influences of Genetics and Early Life Experiences on Intracranial Volume: Insights from a Comprehensive MRI Study

Abstract

Recent research has elucidated the significance of intracranial volume (ICV) as an indicator of maximal brain development, correlating closely with cognitive abilities in later life. This study, originating from the Study of Latinos-Investigation of Cognitive Aging with MRI (SOL-INCA-MRI), aims to quantify ICV among first- and second-generation Hispanic and Latino adults. In addition to measuring ICV, the research assesses the heritability of ICV, as well as its associations with specific genetic variants, both on an individual basis and through a collective genetic risk score (GRS). Furthermore, the investigation explores early life environmental measures, specifically focusing on nativity, age of immigration, and parental education.

In a cohort consisting of 1,781 unrelated participants from the SOL-INCA-MRI study, the estimated heritability for ICV was found to be approximately 19%, with a 95% confidence interval ranging from 0.1% to 56%. This finding suggests that genetic factors play a notable, albeit not sole, role in determining ICV within this population. Of the ten genetic variants that were examined, four exhibited significant associations with ICV, indicating a potential biological link worth exploring in future research. Notably, an increase of one standard deviation in the ICV-GRS was associated with a considerable increase in ICV, quantified at 10.37 cm.

The implications of these findings extend beyond mere statistics. Understanding the genetic underpinnings of brain structural metrics like ICV can offer insights into the cognitive health of Hispanic and Latino adults, a demographic that has been historically underrepresented in such studies. Moreover, the research highlights the influence of early life experiences and familial educational background on brain development. By incorporating nativity and immigration age, the study adds a crucial layer of context that reflects the unique life experiences of Hispanic and Latino populations in the United States.

As the field of cognitive aging continues to evolve, studies like SOL-INCA-MRI underscore the necessity of inclusive research that captures the diversity of human experience. Future inquiries should aim to delve deeper into how both genetic and environmental factors converge to shape cognitive trajectories across different populations, ultimately enriching our understanding of brain health and development.