Epigenomic study pinpoints critical period for prenatal nutrition in development of fetus.

Researchers at Columbia University and Leiden University have found that children whose mothers were malnourished at famine levels during the first 10 weeks of pregnancy had changes in DNA methylation known to suppress genes involved in growth, development, and metabolism documented at age 59. This is the first study to look at prenatal nutrition and genome-wide DNA patterns in adults exposed to severe under-nutrition at different periods of gestation. The opensource study is published in the International Journal of Epidemiology.

The current study evaluated how famine exposure, defined as 900 calories daily or less, during the Dutch Hunger Winter of 1944-1945 affected genome-wide DNA methylation levels. The researchers also studied the impact of short-term exposure, pre-conception and post-conception. The study used blood samples of 422 individuals exposed to the famine at any time during gestation and 463 controls without prenatal famine exposure.

The team examined individuals born between February 1945 and March 1946 whose mothers were exposed to the famine during or immediately preceding pregnancy, individuals conceived between March and May 1945 at the time of extreme famine, and controls born in the same institutions whose mothers did not experience famine while pregnant as well as sibling controls who were also not exposed to famine in pregnancy.

The data findings show associations between famine exposure during weeks 1-10 of gestation and DNA changes, but not later in pregnancy. DNA methylation changes were also seen among individuals conceived at the height of the famine between March and May 1945 who were not exposed to all 10 weeks of early gestation.

The results showed that the first ten weeks of gestation is a uniquely sensitive period when the blood methylome, or whole-genome DNA methylation, is especially sensitive to the prenatal environment.  This is the period when a woman may not even be aware that she is pregnant.

Earlier studies from the researchers in other populations in the Netherlands examined the long-term impact of famine exposure and identified early gestation as the most critically sensitive period. Their work among over 45,000 military recruits revealed that famine exposure in the first pregnancy trimester was associated with a 10-percent increase in mortality at age 63 years.

The team surmise that further analysis of health outcomes among men and women with famine exposure is now needed. The researcher state that they are now looking if DNA-methylation can make a difference for obesity and diabetes risk in this population, adding that they are also interested in sex-specific effects in larger populated studies.

Source:  Mailman School of Public Health, Columbia University

Genome-wide DNA study shows lasting impact of malnutrition in early pregnancy - healthinnovations

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