In a study published in the journal PLoS Genetics, researchers at the University of Bristol searched for the effects of heavy smoking using the UK Biobank cohort; as well as recognizing several known adverse effects such as on lung health, they also found heavy smoking could influence appearance.
Heavy smoking has a damaging effect on facial aging. Image credit: Jui Magicman.
Some people carry one or two copies of a genetic variant that is associated with heavier tobacco use.
To identify the effects of heavier smoking, scientists can separate out the effects of the genetic variant via tobacco use from other possible effects associated with carrying the variant that are unrelated to tobacco use.
To simultaneously identify these two types of effects, University of Bristol’s Dr. Louise Millard and colleagues used a novel combination of two data analysis approaches: the Mendelian randomization phenome-wide association study approach and gene-by-environment interaction tests.
The researchers searched across 18,000 traits from the UK Biobank cohort.
They separated people into two groups: the first contained never-smokers, and the second included current and former smokers.
The authors reasoned that the smoking group would reveal the effects of tobacco exposure, while the never-smokers would show them any unrelated effects of the genetic variant.
They found their approach worked, as their results included several known effects of heavier smoking e.g. on lung function, risk of chronic obstructive pulmonary disease and skin cancer.
They also identified an interesting potential effect of heavier smoking on more facial aging.
“We proposed a novel approach that can be used to search for causal effects of health exposures, and demonstrated this approach to search for the effects of smoking heaviness,” Dr. Millard said.
“We searched across thousands of traits to identify those that may be affected by how heavily someone smokes.”
“As well as identifying several known adverse effects such as on lung health, we also identified an adverse effect of heavier smoking on facial aging.”
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L.A.C. Millard et al. 2019. MR-pheWAS with stratification and interaction: Searching for the causal effects of smoking heaviness identified an effect on facial aging. PLoS Genet 15 (10): e1008353; doi: 10.1371/journal.pgen.1008353
