Table 1.

Study population characteristics

	Carbon monoxyde (CO) level		P value
	0-9 ppm (n=64)	> 9ppm (n=21)
Age (years)1	43±8	43±7	0.92
Job duration (years)1	13±7	11±4	0.09
BMI (Kg.m-2)1	28±9	32±6	0.57
years of education1	7±4	5±3	0.06
incomes per day (XOF)2	3680±910	3980±785	0.16
Any co-morbidity (%)	24	14	0.54
Exposure to tobacco smoke (%)	36	24	0.43

¹Expressed as mean±standard deviation

²XOF=local currency in Benin