Table 3.

Risk ratios for development of rapid decline in FEV₁ according to quartile of mean CAL.

	Mean CAL				P for Trend
	Q1 (Low) n = 414	Q2 n = 410	Q3 n = 410	Q4 (High) n = 416
Rapid decline in FEV1, n	79	111	111	121
Crude RR (95% CI)	1.00 (reference)	1.42 (1.10–1.83)	1.42 (1.10–1.83)	1.52 (1.19–1.95)	0.001
Adjusted RR (95% CI)*	1.00 (reference)	1.32 (1.03–1.70)	1.33 (1.03–1.72)	1.35 (1.04–1.76)	0.039

Quartiles for mean clinical attachment loss were <1.46, 1.47–1.80, 1.81–2.23, ≥2.24 mm.

CAL = clinical attachment loss; FEV₁ = forced expiratory volume in one second; RR = risk ratio; CI = confidence interval.

*Adjusted for sex, age, occupation, diabetes mellitus, body mass index, physical activity, Brinkman index, alcohol intake.