Researchers found the year in which an individual was born could influence the impact of an obesity-related gene variant.
A research team revealed the impacts of a variant in the FTO gene that has been previously linked with obesity is largely determined by birth year, the Massachusetts General Hospital reported.
"Looking at participants in the Framingham Heart Study, we found that the correlation between the best known obesity-associatedgene variant and body mass index increased significantly as the year of birth of participants increased," said James Niels Rosenquist of the Massachusetts General Hospital (MGH) Department of Psychiatry, lead author of the report. "These results - to our knowledge the first of their kind - suggest that this and perhaps other correlations between gene variants and physical traits may very significantly depending on when individuals were born, even for those born into the same families."
The data was gathered between the years of 1971 and 2008 and encompassed participants ranging in age from 27 to 63. The relationship between Body Mass Index (BMI) and FTO variants inherited at birth were measured eight times during the study period; the team found a link between the two factors was only seen in individuals born in later years.
There was no correlation between FTO and BMI in those born before 1942, but in participants born after that year the correlation was twice as strong as was reported in previous studies.
The researchers were not able to determine exactly what caused this correlation, but suggested post-World War II factors such as increased reliance on technology (rather than physical labor) and consumption of high-calorie foods could be factors that contribute to obesity risk in this population.
"We know that environment plays a huge role in the expression of genes, and the fact that our effect can be seen even among siblings born during different years implies that global environmental factors such as trends in food products and workplace activity, not just those found within families, may impact genetic traits," Rosenquist said. "Our results underscore the importance of interpreting any genetic studies with a grain of salt and leave open the possibility that new genetic risk factors may be seen in the future due to different genetically driven responses to our ever-changing environment."
The findings were published in a recent edition of the journal PNAS.
