Table 2

Longitudinal data on lung function decline in smokers, exsmokers, quitters and nonsmokers without chronic respiratory symptoms

First author [ref.]	Subjects n	Sex	Age^§ yrs	Cumulative cigarette consumption pack-yrs			Follow-up yrs	Decline in FEV₁ mL·yr⁻¹
First author [ref.]	Subjects n	Sex	Age^§ yrs	Sm	Exsm	Quitter	Follow-up yrs	Sm	Exsm	Quitter	Nonsm
Burchfiel 45	4451^¶¶	M	54				6	34*	22	23^#, 30^ƒƒ	22
Sherrill 44	477^¶¶	M	46 (45–47)	49	41		7	17	27		16
		F	46 (41–52)	43	19		7	14	15		12
Bosse 46	850^¶¶	M	42 (39–44)	21		22	5	85		57^#	53
Camilli 47	1705^¶¶	M	49	32	32	32	9.4	19⁺	4	6	6
		F	49	28	17	18	9.4	7⁺	−0.7	−4	0.4
Tashkin 25	2401^¶¶	M	45	41	27	39	5	70⁺	52	62	56
		F	45	31	16	27	5	54⁺	38	38	42
Sherman 16	3948^¶¶	M	48	32	24		12	44⁺	35		33
		F	49	22	12		12	34⁺	27		28
Xu 49	4554^¶¶	M	15–54				24	19, 26, 33*^,++	20	6^#	6
		F	15–54				24	15, 20, 30*^,++	19	3^#	15
Xu 39	5572^¶¶	M	25–78				6	53⁺	34	41^#	38
		F	25–78				6	38⁺	30	29^#	29
Lange 8	7764^¶¶	M	<55				5	22, 42^§§	27	17, 36^§§	21
			>55				5	52, 56^§§	36	11, 43^§§	34
		F	<55				5	17, 30^§§	18	15, 9^§§	13
			>55				5	39, 48^§§	32	28, ^§§	32
Townsend 55	4926	M	47				6–7	59⁺	44	50	51
Pelkonen 51^ƒ	411^¶¶	M	47				30	52⁺	36	40	35
	1007^¶¶	M	49	27	18	25	15	66⁺	49	56	46
Krzyzanowski 52	1824^¶¶	M	40 (19–70)				13	60*^,¶	50	68	47
		F	40 (19–70)				13	42	38	37	38
Krzyzanowski 56^##	640^¶¶	M	45				12	11.7		6.8	6.3
		F	48				12	10.5		1.6	7.6
	1738^¶¶	M	40				12	14		16.5	8.7
		F	40				12	6.6		1.4	6.1
Taylor 53	227^¶¶	M	51–61				7.5	11⁺	8		6.6

FEV₁: forced expiratory volume in one second
Sm: smokers without chronic respiratory symptoms
Exsm: exsmokers who quitted smoking before the start of the study
Quitter: healthy smoker at start of study, exsmoker at end of study
Nonsm: nonsmoker
M: male
F: female
^§: mean, range or mean (range)
^ƒ: part of population followed for 30 yrs (n=411), duration of smoking rather than cumulative cigarette consumption described and FEV_0.75 rather than FEV₁ measured
^##: two populations studied: Tucson, AZ, USA (n=640), and Cracow, Poland (n=1,738)
^¶¶: general population study
⁺⁺: light (<15 cigarettes·day⁻¹), moderate (15–24 cigarettes·day⁻¹), heavy (>24 cigarettes·day⁻¹) smokers
^§§: light (<15 cigarettes·day⁻¹), heavy (>15 cigarettes·day⁻¹) smokers
^ƒƒ: >2 ys, <2 yrs
*: p<0.05 versus nonsmokers
^#: p<0.05 versus smokers
^¶: p<0.05 versus exsmokers
⁺: p<0.05 versus all other groups