People born before 1942 are less likely to be affected by a variant to a gene linked to obesity risk than those who are born after 1942. The effect is stronger in those born in later years, finds a fascinating research.
The findings underscores the effect of broad environmental changes to increase in obesity in recent times.
"We found that the correlation between the best known obesity-associated gene variant and body mass index increased significantly as the year of birth of participants increased," said lead author James Niels Rosenquist from Massachusetts General Hospital (MGH).
The researchers used data gathered between 1971 and 2008, when participants ranged in age from 27 to 63.
Looking at the relationships between participants' body mass index (BMI), as measured eight times during the study period, and the FTO gene variants they had inherited.
The previously reported association between a specific FTO variant and BMI was seen, on average, only in participants born in later years.
While there was no correlation between the obesity-risk variant and BMI for those born before 1942, in participants born after 1942 the correlation was twice as strong as reported in previous studies.
Post-World War II factors such as increased reliance on technology rather than physical labour and the availability of high-calorie processed foods are likely contributors to the environmental effects of obesity, the authors noted.
The study appeared in the journal PNAS Early Edition.