Table 2. Positive predictive value of a positive test calculated on the 1991 cohort and 2006 cohort

Table 2A	1991 cohort, all	2006 cohort, all
	Composite outcome 1991–2017, n (95% CI)	Composite outcome 2006–2017, n (95% CI)
	Event	No event	Total	Event	No event	Total
FEV₁/FVC <70	27	25	52	56	82	138
FEV₁/FVC 70–75	33	62	95	46	158	204
FEV₁/FVC >75	131	627	758	115	820	935
Total	191	714	905	217	1060	1277
PPV <70		0.52 (0.38 to 0.66)		0.41 (0.32 to 0.49)
PPV 70–75		0.35 (0.25 to 0.44)		0.23 (0.17 to 0.28)
PPV >75		0.17 (0.15 to 0.20)		0.12 (0.10 to 0.14)

Table 2B	1991 cohort, respiratory symptoms			2006 cohort, respiratory symptoms
	Composite outcome 1991 – 2017 , n (95% CI)			Composite outcome 2006 – 20 17 , n (95% CI)
	Event	No event	Total	Event	No event	Total
FEV₁/FVC <70	14	9	23	30	14	44
FEV₁/FVC 70–75	19	12	31	18	32	50
FEV₁/FVC >75	37	93	130	42	133	175
Total	70	114	184	90	179	269
PPV <70		0.61 (0.41 to 0.81)		0.68 (0.54 to 0.82)
PPV 70–75		0.61 (0.44 to 0.78)		0.36 (0.23 to 0.49)
PPV >75		0.28 (0.21 to 0.36)		0.24 (0.18 to 0.30)
Table 2C	1991 cohort, smoking history			2006 cohort, smoking history
	Composite outcome 1991 – 2017 , n (95% CI)			Composite outcome 2006 – 20 17, n (95% CI)
	Event	No event	Total	Event	No event	Total
FEV₁/FVC <70	23	21	44	37	49	86
FEV₁/FVC 70–75	27	44	71	29	89	118
FEV₁/FVC >75	88	371	459	61	331	392
Total	138	436	574	127	469	596
PPV <70		0.52 (0.38 to 0.67)		0.43 (0.34 to 0.52)
PPV 70–75		0.38 (0.27 to 0.49)		0.25 (0.17 to 0.32)
PPV >75		0.19 (0.16 to 0.23)		0.16 (0.12 to 0.19)
Table 2D	1991 cohort, smoking history and respiratory symptoms			2006 cohort, smoking history and respiratory symptoms
	Composite outcome 1991 – 2017, n (95% CI)			Composite outcome 2006 – 20 17, n (95% CI)
	Event	No event	Total	Event	No event	Total
FEV₁/FVC <70	12	8	20	24	9	33
FEV₁/FVC 70–75	15	11	26	12	21	33
FEV₁/FVC >75	31	60	91	24	61	85
Total	58	79	137	60	91	151
PPV <70		0.60 (0.39 to 0.81)		0.73 (0.58 to 0.88)
PPV 70–75		0.58 (0.39 to 0.77)		0.36 (0.20 to 0.53)
PPV >75		0.34 (0.24 to 0.44)		0.28 (0.19 to 0.38)

FEV₁/FVC = forced expiratory volume in 1 second/forced vital capacity. PPV = positive predictive value.