Quitting cigarettes genes or willpower?

New research may help explain why some pregnant women find it difficult to quit smoking

Researchers from the South-West have identified a genetic difference associated with continued smoking through pregnancy.

DNA samples from 2500 pregnant regular smokers were screened for a single DNA letter difference in a group of genes that code for nicotine receptors. The variant has previously been associated with the quantity of cigarettes that regular smokers smoke.

Just 34% of those with two copies of this variant gave up by the last three months of pregnancy compared to 47% carrying other variants. Researchers looked at pregnant women because they have a strong incentive to quit but believe their findings may be relevant for other smokers.

Co-author of the paper, Professor Tim Frayling, suggested there were parallels with genes affecting obesity in that both these health issues are commonly blamed on a lack of will power but in fact are partly associated with our genetics.