Table 1: Characteristics of the study population undergoing screening colonoscopy in the New Hampshire Colonoscopy Registry from 2004–2006.

   TotalN (%) 5,395
Smoking
 No pack-years2,865 (53)
 15 pack-years or fewer1,243 (23)
 More than 15 pack-years1,287 (24)
Family H i s t o r y a
 Negative4,649 (86)
 Positive746 (14)
Gender
 Male2,284 (42)
 Female3,111 (58)
Adenoma
 None4,689 (87)
 One or more706 (13)
Adenoma Size
 No Adenoma4,672 (87)
5 mm318 (6)
 5–9 mm268 (5)
1 cm120 (2)
Mean (SO)
Mean Age (yrs.)56 ( ± 11)

a F a m i l y history was defined as a reported diagnosis of colon or rectal cancer in a mother, father, sibling, or child of the patient.