The Influence of Cigarette Smoking on Gingival Bleeding and Serum Concentrations of Haptoglobin and Alpha 1-Antitrypsin

Table 5

Regression analysis for plaque index and factors.

Model	Beta	𝑃 value	95% CI	S/NS
Constant	—	0.001	48.703, 63.633
Duration of smoking in years	0.438	0.001	0.333, 0.792	S
Cotinine (ng/dL)	−0.353	0.001	−0.195, −0.064	S

All of the variables are significant and protective.