Is the genetic code or postal code that influences the chances of a child's life?

Most children inherit both their postal code and their genetic code from their parents. However, if genetic factors influence where families live and the health and educational success of their children, neighborhood improvement may not be enough. The most recent research conducted at Columbia University's Mailman School of Public Health and the University of California, Irvine provides insight into the controversial question of whether the neighborhoods in which children live affect their health. their chances in life.

This is the first study to collect genetic and geographical data to test the links between children's neighborhoods and genetic risk. The results are published online in Nature human behavior.

The research team led by Dan Belsky, Ph.D. Assistant Professor of Epidemiology at the Columbia Mailman School and Candice Odgers of the University of California, Department of Psychology at the University of California. Irvine, have linked genomic, geographical, health and educational data of thousands of children living in Britain and Wales. They found that children growing up in disadvantaged neighborhoods also had a higher genetic risk for poor school performance and earlier pregnancy. The authors reproduced their findings in the American study Add Health, in which they found that gene-neighborhood correlations could accumulate from generation to generation as young people with high genetic risk of low education and a younger age were both born. moved into poorer neighborhoods.

"But genetic risk alone was not enough to explain why children from the poorest and wealthiest neighborhoods received less education and were more likely to be out of school, unemployed, or in education ( NEET) at the end of adolescence, "said Belsky, also with the Columbia Aging Center. "The data on education could account for only a fraction (10-15%) of the link between neighborhood risk, low educational qualifications and NEET status, suggesting that there are many opportunities for neighborhoods influence these results. "

"Surprisingly, for obesity, one of the most prevalent and costly health problems for this generation, we found no link between neighborhood risk and genetic risk ", observed Odgers. "Children who grew up in underprivileged neighborhoods were more likely to become obese by age 18, but they did not present higher genetic risk of obesity than their peers living in more affluent neighborhoods."

Similarly, with respect to mental health issues, children in the most disadvantaged neighborhoods had more symptoms of mental disorders, but there was no indication that the reason for this link was due to genetic risk. For physical and mental health problems, both the postal code and the genetic code predicted the future of the child.

The analyzes were based on data from the Twin Longitudinal Environmental Risk Study (E-Risk), which followed 2232 twins born in England and Wales in 1994-1995, and the national longitudinal study of Adolescent health to the adult, which followed 15,000 American high schoolers to adulthood. For "polygenic scoring", the researchers combined genome information based on recent genome-wide association studies (GWAS) on obesity, schizophrenia, age at first birth and the level of instruction. The neighborhood risk assessment and neighborhood mobility analysis tools are described in Supporting Details.

The use of Google Street View and high-resolution geospatial data allowed researchers to capture the key features of the neighborhoods in which children lived. Odgers developed the virtual assessments used in the study. "Advances in genomics and geospatial analysis are rapidly positioning us to make new discoveries, which have allowed us to identify outcomes, such as obesity and mental health, where neighborhoods are most likely to be affected." Have unique impacts. " But, she added, "it is only a first step in addressing the crucial question of whether changing neighborhood conditions can improve the lives of children in these areas."

"In our study, the polygenic risk scores showed a link between genetics and neighborhoods for early pregnancy and poor school performance.This conclusion suggests that we should take neighborhoods into account when interpreting the results. studies on genes related to these findings and genes when looking at the effects of neighborhoods, "said Belsky, but, he says," polygenic risk scores are an evolving and yet flawed tool. " . They can help us check if genes and neighborhoods are linked. But they can not tell us how. "

Genetic risk accounted for only a fraction of the differences between children living in different types of neighborhoods. According to Belsky and Odgers, this gives a reason to hope that "targeting neighborhoods – especially for physical and mental health – will be enough to improve outcomes in children's lives."