Table 5 Arithmetic mean differences in lung function (end of trial minus baseline).

Outcome	N	Difference (95% CI)	p Value
FEV1 (l)
Placebo	98	−0.05 (−0.10 to 0.01)	0.089
Selenium	99	−0.04 (−0.11 to 0.04)	0.36
Selenium‐placebo difference	197	0.01 (−0.08 to 0.10)	0.81
FEF25–75 (l/s)
Placebo	98	−0.02 (−0.15 to 0.10)	0.73
Selenium	99	−0.03 (−0.14 to 0.08)	0.59
Selenium‐placebo difference	197	−0.01 (−0.18 to 0.16)	0.92
FEV1/FVC ratio
Placebo	98	0.01 (−0.01 to 0.02)	0.55
Selenium	99	−0.00 (−0.01 to 0.01)	0.95
Selenium‐placebo difference	197	−0.01 (−0.03 to 0.01)	0.58
FEF25–75/FVC ratio
Placebo	98	0.01 (−0.03 to 0.05)	0.67
Selenium	99	−0.00 (−0.03 to 0.03)	0.9
Selenium‐placebo difference	197	−0.01 (−0.06 to 0.04)	0.68

FEF, forced expiratory flow; FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity.