Fetal exposure to Great Depression economic hardship linked to accelerated aging
People who were exposed in utero to poor economic conditions during the Great Depression may experience accelerated aging in later life, according to an NIA-funded study published in Proceedings of the National Academy of Sciences. The results suggest that the fetal environment plays a critical role in longevity and healthy aging.
As people age, their cells accumulate changes that may lead to increased vulnerability to disease. Such changes are epigenetic, meaning they affect the way genes are expressed without altering the underlying DNA sequence. While epigenetic change is a normal part of biological functioning, different lifestyle, behavioral, and environmental factors can also affect how genes work. A growing body of research suggests that prenatal exposure to adverse environmental factors, such as maternal malnutrition and stress, may lead to epigenetic changes that influence biological aging later in life.
Scientists have developed methods to measure biological age by examining the epigenome, which contains a record of changes to a cell’s DNA. Biological age indicates how much aging-related damage has occurred inside your body’s cells and tissues, and is different than chronological age, the number of years lived beginning at birth. People with biological ages that are older than their chronological ages are described as having accelerated aging and appear to be more likely to have age-related diseases and shorter lifespans.
For this study, researchers from the University of Wisconsin-Madison and American University examined whether exposure to the Great Depression as a developing fetus was linked to accelerated aging. The researchers analyzed epigenetic aging measures in blood samples collected from 832 participants in the University of Michigan Health and Retirement Study. Using wage index data from the Bureau of Economic Analysis from 1929 to 1940, the scientists were able to estimate features of the economic environment (e.g., unemployment rates) in the year and state in which the participant was in the womb. They found that people who were exposed to worse economic conditions during fetal development were more likely to have a biological age older than their chronological age, suggesting accelerated aging.
The scientists also analyzed whether exposure to economic adversity during early life was linked to accelerated aging. They discovered that exposure to the same level of economic adversity experienced after birth was not linked to faster aging, suggesting that fetal development may be a uniquely important period in laying the foundation for longevity and healthy aging.
This research suggests that exposure to adverse economic conditions during fetal development is linked to accelerated aging. Future studies could explore whether differences in the level of prenatal care, such as nutrition, maternal stress, or other factors, may be responsible for this link. The authors note that the study was limited in that they were not able to determine whether specific trimesters of pregnancy were particularly important because monthly economic data during the Great Depression was not available for each state. Overall, the study supports the idea that the seeds of healthy aging are planted in utero.
This research was supported in part by NIA grants K99AG056599, R00AG056599, P30AG012846, P30AG017265, and P30AG017266.
Reference: Schmitz LL and Duque V. In utero exposure to the Great Depression is reflected in late-life epigenetic aging signatures. Proc Natl Acad Sci U S A. 2022. Epub Nov 8. doi: 10.1073/pnas.2208530119.