Table 3

Calcium and vitamin D treatment and the risk of serrated polyps during treatment and observational phase

OutcomeTreatment phase: n=2058* Observational: n=1108
N with event/
N followed (%)
Crude
RR (95% CI)
P valueAdjusted
aRR (95% CI)
P valueN with event/
N followed (%)
Crude
RR (95% CI)
P valueAdjusted
aRR (95% CI)
P value
Any serrated polyp
No vitamin D278/1031 (27.0)ReferenceReference 159/550 (28.9)ReferenceReference
Vitamin D287/1027 (28.0)1.04
(0.90 to 1.19)
0.621.01
(0.87 to 1.17)
0.90170/558 (30.5)1.05
(0.88 to 1.26)
0.571.04
(0.86 to 1.25)
0.71
No calcium203/763 (26.6)ReferenceReference114/418 (27.3)ReferenceReference
Calcium231/764 (30.2)1.14
(0.97 to 1.33)
0.121.15
(0.98 to 1.36)
0.10136/428 (31.8)1.17
(0.95 to 1.44)
0.151.21
(0.97 to 1.50)
0.09
Placebo99/378 (26.2)ReferenceReference56/205 (27.3)ReferenceReference
Vitamin D+calcium117/384 (30.5)1.16
(0.93 to 1.46)
0.191.15
(0.92 to 1.46)
0.2372/218 (33.0)1.21
(0.90 to 1.62)
0.201.24
(0.92 to 1.67)
0.16
Any HP
No vitamin D249/1029 (24.2)ReferenceReference132/548 (24.1)ReferenceReference
Vitamin D245/1027 (23.9)0.99
(0.85 to 1.15)
0.860.96
(0.82 to 1.13)
0.65139/555 (25.1)1.04
(0.85 to 1.28)
0.711.03
(0.83 to 1.27)
0.80
No calcium176/763 (23.1)ReferenceReference101/418 (24.2)ReferenceReference
Calcium204/763 (26.7)1.16
(0.97 to 1.38)
0.101.18
(0.99 to 1.42)
0.07103/423 (24.4)1.01
(0.79 to 1.28)
0.951.05
(0.82 to 1.35)
0.71
Placebo87/378 (23.0)ReferenceReference50/205 (24.4)ReferenceReference
Vitamin D+calcium102/384 (26.6)1.15
(0.90 to 1.48)
0.261.16
(0.90 to 1.49)
0.2653/215 (24.7)1.01
(0.72 to 1.42)
0.951.03
(0.73 to 1.45)
0.87
Any SSA/P
No vitamin D42/1008 (4.2)ReferenceReference26/536 (4.9)ReferenceReference
Vitamin D58/1006 (5.8)1.38
(0.94 to 2.04)
0.101.27
(0.86 to 1.88)
0.2236/550 (6.6)1.35
(0.83 to 2.20)
0.231.31
(0.82 to 2.10)
0.26
No calcium36/745 (4.8)ReferenceReference13/409 (3.2)ReferenceReference
Calcium39/740 (5.3)1.09
(0.70 to 1.70)
0.701.03
(0.66 to 1.60)
0.9136/417 (8.6)2.72
(1.47 to 5.03)
0.0012.66
(1.44 to 4.89)
0.002
Placebo14/369 (3.8)ReferenceReference5/201 (2.5)ReferenceReference
Vitamin D+calcium21/372 (5.7)1.49
(0.77 to 2.88)
0.241.26
(0.67 to 2.39)
0.4722/216 (10.2)4.09
(1.60 to 10.50)
0.0033.82
(1.26 to 11.57)
0.02
  • Analyses of no vitamin D versus vitamin D include all randomised participants; analyses of no calcium versus calcium and of neither agent versus both agents are restricted to full factorial participants.

  • *Subjects who had an examination at least 1 year after randomisation and had sufficient pathology to determine at least one of the serrated outcomes.

  • †Subjects followed after treatment period who had sufficient pathology to determine at least one of the serrated outcomes

  • ‡Adjusted for age, sex, clinical centre, race (white, black, other/missing), BMI, smoking status (never, former, current), anticipated surveillance interval (3 or 5 years; treatment phase only), randomisation arm of randomisation (two group or full factorial), number of baseline serrated polyps (0, 1, 2+). Where necessary due to sparse data, clinical centre was grouped by prevalence of serrated lesions at baseline into low (Georgia, Iowa, Minnesota and California), medium (New Hampshire, Colorado, South Carolina and Puerto Rico), high (Texas, Ohio and North Carolina).

  • aRR, adjusted risk ratio; BMI, body mass index; HP, hyperplastic polyp; SSA, sessile serrated adenoma.