Interaction between smoking and functional polymorphism in the TGFB1 gene is associated with ischaemic heart disease and myocardial infarction in patients with rheumatoid arthritis: a cross-sectional study

Table 6 Multivariate stepwise logistic regression analysis of variables associated with ischaemic heart disease and myocardial infarction

Ischemic heart disease (model 1^a)				Myocardial infarction (model 2^b)
Variable	Regression coefficient	OR (95% CI)	Pvalue	Variable	Regression coefficient	OR (95% CI)	Pvalue
^cSmoking+TGFB1+868TC	1.012	2.75 (1.59-4.75)	0.0003	^cSmoking+TGFB1+868TC	0.948	2.58 (1.33-4.99)	0.0049
Age, per year	0.032	1.03 (1.01-1.06)	0.023	RF-positive	0.655	1.93 (0.93-3.99)	0.078
Male	0.744	2.10 (1.21-3.65)	0.0080	Male	0.972	2.64 (1.37-5.10)	0.0038
CRP ≥ 10 mg/L	1.030	2.80 (1.57-5.01)	0.0005	CRP ≥ 10 mg/L	0.810	2.25 (1.11-4.56)	0.025
Hypercholesterolemia	1.162	3.20 (1.69-6.04)	0.0003	Hypercholesterolemia	1.196	3.31 (1.58-6.91)	0.0014
^dDiabetes	1.198	3.31 (1.36-8.06)	0.0083	Hypertension	1.009	2.74 (1.36-5.53)	0.0048

^aPatients with ischemic heart disease (IHD) versus those without IHD; ^bpatients with myocardial infarction (MI) versus all non-MI patients; ^cpatients who have ever smoked and carry the TGFB1+868 TC genotype in comparison with all remaining patients; ^dtype I or type II diabetes. Forward stepwise selection was used to determine the variables most strongly associated with IHD and MI. Variables excluded by the stepwise procedure for IHD were disease duration, hypertension, erythrocyte sedimentation rate (ESR), rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), body mass index (BMI), methotrexate treatment, steroid treatment, erosive disease, and nodular disease. Variables excluded by the stepwise procedure for MI were age, disease duration, ESR, anti-CCP, BMI, diabetes, methotrexate treatment, steroid treatment, erosive disease, and nodular disease. CI, confidence interval; CRP, C-reactive protein; OR, odds ratio; RF, rheumatoid factor; TGFB1, transforming growth factor-beta-1.

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