Table 2 Ordinary least‐squares regression on the annual number of days of sickness among Swedish adults during 1988–91.

	Full sample	Males	Females
Current smoker	10.69 (8.17 to 13.20)	10.70 (7.24 to 14.15)	10.63 (6.99 to 14.27)
Former smoker	3.09 (0.69 to 5.49)	3.48 (0.34 to 6.63)	2.93 (−0.68 to 6.54)
Never smoker (reference category)	na	na	na
Observations	14 272	7020	7252

na, not applicable.