Smoking, season, and detection of chlamydia pneumoniaeDNA in clinically stable COPD patients

BMC Infectious Diseases

Table 3 Clinical predictors of forced expiratory volume in one second among 93 patients with chronic obstructive pulmonary disease.

	Beta Coefficient (95% Confidence Interval)^a
Risk Factor	Entire Study Group	Age ≤ 65 years (n = 34)	Age > 65 years (n = 59)
Age (L/year)	-0.03 (-0.04, -0.01)^b	-0.05 (-0.08, -0.02)^b	-0.01 (-0.04, 0.02)
Male	0.43 (0.21, 0.66)^b	0.35 (-0.03, 0.74)^d	0.41 (0.12, 0.70)^c
Current Smoker	-0.17 (-0.41, 0.08)	-0.40 (-0.80, 0.00)^d	-0.05 (-0.36, 0.27)
Chlamydia pneumoniae DNA^e	-0.16 (-0.41, 0.10)	-0.40 (-0.86, 0.06)^d	-0.10 (-0.43, 0.23)
November to April	0.19 (-0.04, 0.41)	0.19 (-0.20, 0.57)	0.17 (-0.12, 0.47)

^a Multiple linear regression beta coefficient (litres) associated with the presence of clinical variables for prediction of FEV₁ (SPSS). Age in years, all other variables coded as present (1) or absent (0). ^b P < 0.001 ^c P < 0.05 ^d P < 0.10 ^e C. pneumoniae DNA detected in peripheral blood mononuclear cells or induced sputum by nested polymerase chain reaction [14]

ISSN: 1471-2334