Exclusive cigar smoking in the United States and smoking-related diseases: A systematic review

Table 2 Studies in meta-analysis of chronic obstructive pulmonary disease and exclusive cigar smoking¹

Study name2	Data source	Study type	Years of follow-up	Sex	Age group	Study size3
CPS I	Shanks et al[23], 1998	P	13	M	35+	442455
DORN (US veterans study)	Kahn[27], 1966	P	8	M	35-84	2480464
KAISER	Iribarren et al[13], 1999	P	25	M	30-85	17774
NLMS	Christensen et al[17], 2018	P	26	C	35-80	146529

¹Compared with never smoking any tobacco product.

²Study name is an identifier assigned by the authors based on the published study name or the name of the first author of the source paper. This identifier is used in the meta-analysis output. Note that study KAISER was included in sensitivity analysis only.

³Study size: Total number of participants in the study, irrespective of smoking habits but taking account of sex.

⁴See Table 1 for study size. P: Prospective; M: Male; C: Combined male and female.