Psychological effects of colorectal cancer screening: Participants vs individuals not invited

Table 1 Demographic characteristics of the three randomized groups measured at baseline

	FS (Std residual)	FIT (Std residual)	Control (Std residual)	P comparing 3 groups
Norwegian nationality, %	95.9% (0.4)	94.6% (-0.2)	94.5% (-0.2)	0.08
Not married/cohabitant, %	18.0% (-2.0)1	20.0% (0.0)	22.0% (2.0)1	< 0.01
Higher education, %	45.3% (-0.8)	43.6% (-2.1)1	51.7% (3.2)1	< 0.01
Employed, %	48.9% (-0.9)	49.6% (-0.6)	52.9% (1.6)1	0.03
Women, %	50.1% (-1.0)	52.4% (0.6)	52.2% (0.4)	0.25
Mean age, yr	63.5	62.5	62.7	< 0.012

¹Standardized residuals outside ± 1.96 are considered statistically significant;

²ANOVA. FS: Flexible sigmoidoscopy; FIT: Faecal immunochemical test.

Table 2 Mean anxiety, depression and health-related quality of life change scores from baseline to 1-year follow-up for participants with positive and negative screening results, the two screening groups and the control group

	Control group	Positive	Negative	FS	FIT	Screening group
		(Cohen’s d)	(Cohen’s d)	(Cohen’s d)	(Cohen’s d)	(Cohen’s d)
Anxiety	0.05	0.12	0.13	0.17	0.09	0.13
		(-0.03)	(-0.04)	(-0.05)	(-0.02)	(-0.04)
Depression	0.15	-0.06	0.20	0.20	0.16	0.19
		(0.10)	(-0.02)	(-0.02)	(-0.01)	(-0.02)
SF-12
PF	-1.16	-3.831	-1.50	-1.13	-2.12	-1.71
		(0.14)	(0.02)	(-0.01)	(0.05)	(0.03)
RP	-1.86	-0.97	-3.54	-4.051	-2.77	-3.39
		(-0.03)	(0.05)	(0.06)	(0.03)	(0.04)
RE	-2.03	-3.37	-2.89	-2.04	-3.67	-2.99
		(0.04)	(0.03)	(0.01)	(0.05)	(0.03)
MH	-0.41	-0.58	-1.28	-1.23	-1.20	-1.23
		(0.01)	(0.06)	(0.05)	(0.05)	(0.05)
GH	-1.81	-2.09	-0.451	0.061	-1.08	-0.571
		(0.02)	(-0.09)	(-0.12)	(-0.05)	(-0.08)
BP	-1.57	0.57	-1.11	-0.73	-1.18	-1.01
		(-0.11)	(-0.02)	(-0.04)	(-0.02)	(-0.03)
VT	-1.44	-0.19	-1.93	-1.24	-2.20	-1.8
		(-0.06)	(0.02)	(-0.01)	(0.04)	(0.02)
SF	-1.10	-1.35	-1.47	-1.50	-1.38	-1.46
		(0.01)	(0.02)	(-0.02)	(0.02)	(0.02)

ANOVA

¹The change from baseline to one year follow up is significantly different from the change observed in the control group. A Cohen’s d effect size above 0.5 is defined as a clinically relevant change. HRQOL dimensions: PF: Physical functioning; RP: Role-physical, limitation associated with physical problems; RE: Role-emotional, limitations associated with emotional problems; MH: Mental Health; GH: General health; BP: Bodily pain; VT: Vitality, energy and happiness; SF: Social Functioning; FS: Flexible sigmoidoscopy; FIT: Faecal immunochemical test; HRQOL: Health-related quality of life.

Table 3 Number of participants scoring above the cut-off for a case of anxiety (≥ 8) at baseline and at 1-year follow-up in the different groups n (%)

Group			Anxiety at 1 yr follow up		P value1	P value2
			Non anxiety	Anxiety case
Control group	Before screening	Non anxiety	1574 (82.5)	91 (4.8)
		Anxiety case	87 (4.5)	57 (8.2)	0.82	Ref.
Screening	Before screening	Non anxiety	3660 (82.9)	250 (5.7)
		Anxiety case	164 (3.6)	343 (7.8)	< 0.01	0.11
FS screening	Before screening	Non anxiety	1683 (84.0)	112 (5.6)
		Anxiety case	61 (3.0)	149 (7.4)	< 0.01	0.06
FIT screening	Before screening	Non anxiety	1977 (82.0)	138 (5.7)
		Anxiety case	103 (4.3)	194 (8.0)	0.08	0.32
Positive screening result	Before screening	Non anxiety	292 (84.0)	16 (4.6)
		Anxiety case	11 (3.2)	28 (8.2)	0.49	0.58
Negative screening result	Before screening	Non anxiety	3368 (82.8)	234 (5.7)
		Anxiety case	153 (3.8)	315 (7.7)	< 0.01	0.11

¹The change observed within the group is statistically significant;

²The change observed within the group is significantly different compared to the observed change within the control group. FS: Flexible sigmoidoscopy; FIT: Faecal immunochemical test.