Table 1. Studies of serrated polyps and age.

Author, year	Study description	n with SPs	Age OR/RR* (95% CI)
All SPs
Erhardt, 2002 [42]	German population Screening/diagnostic colonoscopy	71	≤55 y: 1.00 [ref] >55 y: 1.72 (1.00-2.96)
Morimoto, 2002 [45]	US population (MN) Screening/diagnostic colonoscopy	219	<40 y: 1.0 [ref] 40-49 y: 0.9 (0.4-2.3) 50-59 y: 1.6 (0.7-3.7) 60-69 y: 1.4 (0.6-3.2) ≥70 y: 1.6 (0.5-5.0)
Lieberman, 2003 [33]	US population (veterans) Screening colonoscopy	391	50-54 y: 1.00 [ref] 55-59 y: 1.10 (0.76-1.60) 60-64 y: 1.05 (0.76-1.46) 65-69 y: 1.01 (0.72-1.41) ≥70 y: 0.70 (0.48-1.02)
Omata, 2009 [46]	Japanese population, Diagnostic colonoscopy	132
Burnett-Hartman, 2013 [48]	US population (Group Health, WA) Screening colonoscopy	594
Proximal/large SPs
Wallace, 2009 [52]	US population (multicenter/PPSG) Proximal SPs	261	<61 y: 1.00 [ref] ≥61 y: 0.86 (0.68-1.10)
Min, 2012 [56]	Korean population Proximal SPs	60	≥70: 1.00 [ref] 60-69: 2.13 (0.62-7.29) 50-59: 1.53 (0.45-5.20)
Bouwens, 2013 [51]	Dutch population Proximal, large (>6mm) or dysplastic SPs	141
Burnett-Hartman, 2013 [48]	US population (Group Health, WA) Proximal SPs	199	<50 y: 1.00 [ref] 50-59 y: 1.49 (0.70-3.14) 60-69 y: 1.72 (0.77-3.85) ≥70 y: 1.51 (0.60-3.81)
SSAs
Anderson, 2011 [49]	US population (CT) Pancolonic SSAs	90	Per year increase: 1.05 (1.02-1.08)
Burnett-Hartman, 2013 [48]	US population (Group Health, WA) Pancolonic SSAs	149	<50 y: 1.00 [ref] 50-59 y: 1.63 (0.72-3.67) 60-69 y: 2.09 (0.87-5.00) ≥70 y: 2.19 (0.83-5.76)
Hetzel, 2010 [5]	US population (Boston) Pancolonic SSAs	46	Per year increase†: 1.00 (0.96-1.03)

^*multivariate adjusted OR reported when provided

^†Incidence rate ratio

SP: serrated polyp; SSA: sessile serrated adenoma; OR: odds ratio; RR: risk ratio; CI: confidence interval; PPSG: Polyp Prevention study Group

Red text: statistically significant result