TABLE 4 Cox proportional hazards models for all-cause mortality among the 310 subjects with airflow limitation (AL) at baseline^#

	Model 1^¶	Model 2⁺
Sex
Male	1	1
Female	0.66 (0.50–0.87)*	0.72 (0.55–0.95)*
Age at baseline years	1.10 (1.08–1.12)***	1.10 (1.09–1.12)***
BMI
Normal 18.5–25 kg·m⁻²	1	1
Underweight <18.5 kg·m⁻²	2.29 (1.29–4.06)*	2.27 (1.27–4.07)*
Overweight 25–30 kg·m⁻²	0.71 (0.54–0.93)*	0.79 (0.61–1.03)
Obese ⩾30 kg·m⁻²	1.09 (0.61–1.96)	1.04 (0.56–1.93)
Education for >12 years	0.76 (0.59–0.98)*	0.80 (0.62–1.03)
Smoking status
Never-smoker	1	1
Former smoker	0.99 (0.66–1.48)	1.01 (0.67–1.52)
Current smoker	1.27 (0.83–1.92)	1.29 (0.86–1.94)
Pack-years	1.01 (1.00–1.02)***	1.01 (1.00–1.01)*
AL/asthma groups
AL+/asthma-	1	1
AL+/asthma+	1.58 (1.17–2.12)***	1.27 (0.94–1.73)
FEV₁ % predicted at baseline		0.98 (0.98–0.99)***

Data are presented as hazard ratio (95% confidence interval). BMI: body mass index; FEV₁: forced expiratory volume in 1 s. ^#: defined as FEV₁/forced vital capacity <70%; ^¶: included sex, age, BMI, education, smoking status, pack-years and asthma; ⁺: further adjusted for FEV₁% predicted. *: p<0.05; ***: p<0.001.