First author (year) | Country | Sample | Measurementa | Smoking indicatorsb | Gene(s) | Main findinge | ||
---|---|---|---|---|---|---|---|---|
Size | Male | Age mean | ||||||
(n) | (%) | (year) | ||||||
Zhang, (2014) [8] | Germany | 3588 | 44.4 | 61.7 | MALDI-TOF | Current/former/never smoker (PY, ND, TQ) | F2RL3 | F2RL3 methylation strongly decreased with current smoking intensity and with lifetime cumulative smoking, and reached a plateau at higher current and cumulative smoking intensity. Methylation levels increased with time since cessation, but the time for full recovery was more than 20 years. |
Shenker, (2013) [7] | UK | 81/180c | 81.5/0 | NRd | BPP | Current/former/never smoker (SD, CL) | AHRR, 2q37, 6p21 | Combining four gene loci of AHRR, 2q37, and 6p21 into a single methylation index provided high positive, predictive, and sensitivity values for predicting former smoking status in both test (n = 81, AUC = 0.82) and validation (n = 180, AUC = 0.83) sample sets. |
Breitling, (2012) [23] | Germany | 1100 | 66.6 | 58.0 | MALDI-TOF | Continuing smoker/quit after acute event/quit before acute event/never smoking | F2RL3 | F2RL3 were significantly associated with smoking history of patients with CHD (median methylation intensities at CpG_4, continuing smoker = 0.53; quit after acute event = 0.51; quit before acute event = 0.66; never smoking = 0.74) (p < 0.001). |