Researchers used publicly available data from Gene Expression Omnibus and analyzed patterns in DNA methylation. Previous research revealed methylation changes could predict how people age and reveal responses to such habits as smoking and drinking alcohol. Two specific locations in genome were identified as having an association with smoking and alcohol.
This allowed researchers to estimate each person’s biological age based on methylation levels at 71 locations in the genome. They calculated the difference between biological age and chronological age to determine the relationship between smoking/alcohol and premature aging.
High levels of smoking were associated with premature aging and mild alcohol consumption – one to two drinks a day – was related to healthy (the healthiest, actually) aging. Low levels or high levels of alcohol consumption were linked with poor aging.
Meeshanthini Dogan from the study said, “These new tools allow us to monitor smoking and alcohol use in an objective way, and to understand their effects quantitatively. Furthermore, our methods could be used to analyze any set of 450 BeadChip data, which means that existing data can be used to identify new patterns and that all such results can be easily compared.”
Robert A. Philibert, Ph.D., from the University of Iowa added, “Being able to objectively identify future smokers and heavy alcohol users when they are young, before major health issues arise, can help providers and public health practitioners prevent future problems, improve quality of life, and reduce later medical costs.”
Dogan concluded on potential further study by saying, “We want to study how the intensity of current tobacco and alcohol use and cumulative levels of use throughout a lifetime affect methylation, including what happens when a person quits smoking or drinking. By clarifying at what point the epigenetic changes become tougher to stop or reverse, we can inform decisions about how best to use the limited public health resources we have.”
The study was published in American Society of Human Genetics.