Skip to main content

Table 2 Smoking amounts of COPDs and controls in the included studies.

From: Nicotinic acetylcholine receptor variants associated with susceptibility to chronic obstructive pulmonary disease: a meta-analysis

Study and reference Pack-years of smoking
  Controls (N) COPDs (N)
Bergen cohort from Pillai et al [26] 19 ± 13*(810) 32 ± 19*(823)
Copenhagen City Heart Study from Kaur-Knudsen et al [25] NR NR
COPDGene study from Kim et al [24] 52 ± 29*(335) 37 ± 19*(507)
COPACETIC cohort from Lambrechts et al [23] 38.0 (28.0-46.2) (295) 38.7 (29.7-49.5)(161)
LEUVEN cohort from Lambrechts et al [25] 42.3 (30.0-50.5) (184) 40.0 (30.0-57.0) (475)
NETT/NAS cohorts from Pillai et al [26] 40 ± 28*(472) 66 ± 30*(389)
New Zealand study from Young et al [27] 40 ± 19*(488) 47 ± 20*(458)
  1. Abbreviations: Data were presented as median (25th - 75th percentiles) for COPACETIC and LEUVEN cohorts, and as mean ± SD for other studies. NR, not reported; COPD, chronic obstructive pulmonary disease, defined by spirometric results; * p < 0.05