Table 4.

Logistic regression showing attempts to quit smoking.

Attempts to quit	Case (n)	Control (n)	Odds ratio	P-value
0	6293	14,803	–	–
1	1008	377	5.59 (4.86–6.44)	<0.001
2	282	93	6.43 (4.90–8.43)	<0.001
3	104	20	10.00 (2.87–11.06)	<0.001
4	47	14	5.63 (2.87–11.06)	<0.001