Nichols 2017.

Study characteristics
Methods	Design: Randomized controlled trial Setting: Primark care clinics, UK Recruitment: Mailed letters to patients in GP database
Participants	109 adults who smoked. 55.6% F; mean age 49 years; mean Fagerström score 4.9, av. cpd 18
Interventions	Intervention: participants received an 8‐week smoking cessation program, where a participant is offered a fact sheet on the health risks of smoking (including lung cancer) and the option of the gene‐based test for calculation of lung cancer susceptibility Control: participants received a smoking cessation program without option of gene‐based test
Outcomes	Continuous abstinence at 6m Validation: Expired CO and salivary cotinine, cut‐offs not reported
Funding Source	JN and PG are in receipt of research grants from Lab 21, Cambridge who are marketing the Respiragene test in the UK and Synergenz Bioscience Ltd. who financed the development of the test from its origins in New Zealand
Author's declarations of interest	Authors declared that they had no conflict of interest
Notes	Strategy: Gene‐based test Level: Patient Comparison type: Single component vs. standard care
Risk of bias
Bias	Authors' judgement	Support for judgement
Sequence Generation	Unclear risk	No details reported
Allocation concealment	Unclear risk	No details reported
Blinding of outcome assessors All outcomes	Low risk	Smoking status biochemically validated
Incomplete outcome data All outcomes	Low risk	The overall loss to follow‐up was 43.1% (n = 47/109); 37.0% (n=20/54) in the intervention group and 49.0% (n = 27/55) in the control group were lost to follow‐up at 6 months