Researchers who studied the DNA of thousands of smokers found that two gene variants were linked to nicotine addiction, UPI reported Jan. 30.

The two-part study looked for genetic variations that might predict heavy smoking. The researchers found that variants of the alpha 3 and alpha 5 nicotine-receptor subunit gene appeared to increase the risk of nicotine addiction.

The findings could be useful in developing new smoking-cessation medications, researchers said.

The study was published in the online edition of the journal Molecular Psychiatry.