We detected a huge overlap with the issue of SOC 14 and SOC6. We decided to subsume SOC 6 and  SOC14 into one only result card (SOC 14). Five (5) of our included primary studies provided information on this topic.

In the Australian study by Cole et al, 2003, a pool of 4000 potential invitees aged 50–69 years was randomly selected using postcodes that represented a broad range of socio-economic index. Exposure of this population to screening was low: prior participation in screening had been less than 20%. The study compares gFOBT and two types of FIT: FlexSure OBT and InSure. Both did not require drug or diet restrictions, but InSure had a simplified procedure to sampling stools. It needed two rather than three stools and invitee were asked to sample the stool by brushing the surface of the stool while immersed in toilet bowl water. The content of the brush is transferred by touching one of the two windows of the sample card, and the second stool is separately sampled onto the other window. FelxSure OBT provided to sample three stools (one card per stool) using a spatula similar to that for Hemoccult, keeping the stool clear of toilet bowl water.  Three randomized cohorts of 606 invitees were offered a screening test by mail in 2001. The first 606 were allocated to the gFOBT (Hemoccult SENSA), the second 606 to the FIT (FlexSure OBT) and the third 606 to the FIT (InSure).

For gender, univariate analysis indicated a trend to better participation to screening in women, but this was not statistically significant or confirmed in the multivariate analysis (see fig. 1). Authors conclude that interaction between gender and participation needs more detailed exploration. Univariate analysis also indicated a trend to better participation in those aged 60–69 years than in those in the previous decade but again, this was not statistically significant. Socioeconomic status showed not to be a confounding factor in the study by Cole et al. although authors highlight that other studies showed an influence of this variable. The reasons why these associations were not seen in the Australian study remain might be related to complex cultural factors that vary between populations.

Fig. 1 Table from Cole et al. 2003, p. 121

The Hughes et al study (2005) involved a rural Queensland community in Unites States, with a population of 15,000 of which 4,200 were aged 50 or over.  Overall, 1,219 kits were completed and returned for analysis, with  a participation rate of 36.3%. Participation was significantly higher with the immunochemical kit (χ2=20.7, p<0.001), and women were significantly more likely to comply with testing than men (χ2=24.8, p<0.001).  For those receiving the gFOBT, participation progressively increased with increasing age (27% among those 50-59; 32% among those 60- 69; and 35% among those 70-74 years). In contrast, among recipients of FIT  participation by the youngest (47%) and oldest (49%) age groups were similar (OR=0.98; 95% CI 0.74-1.28 comparing 50-59 year-olds and 70- 74 year-olds), whereas persons aged 60-69 (40%) were less likely to participate (OR=0.73; 95% CI 0.56-0.96 relative to 70-74 year olds).  (see Fig.1).

Fig.1 Table from Hughes et al study (2005), p-361

The association between participation and age was significant at the multivariate level with younger age groups, particularly the 60-69 year olds, less likely to comply compared with the 70-74- year age group. However, there was evidence of interaction between age and kit type (p=0.01; see Figure 2).  For those receiving the guaiac test, participation progressively increased with increasing age (27% among those 50-59; 32% among those 60- 69; and 35% among those 70-74 years). In contrast, among recipients of the immunochemical test, participation by the youngest (47%) and oldest (49%) age groups were similar (OR=0.98; 95% CI 0.74-1.28 comparing 50-59 year-olds and 70-74 year-olds), whereas persons aged 60-69 (40%) were less likely to participate (OR=0.73; 95% CI 0.56-0.96 relative to 70-74 year olds).

Fig 2. Table form Hughes et al study (2005), p-361

In the Hawley et al (2008) a purposive sampling from waiting areas of 3 community health centers was done and patients aged 50-80 recruited. This study is about the declared intention to participate in hypothetical secnarios and its not a community based trial directly comparing screening with different test. Respondents were asked to rate 8 hypothetical CRC screening tests scenarios. Patients demographics included race/ethnicity (White, Hispanic, African Americans) educational attainment, gender and age.

The study found an importance of the variable race/ethnicity. Hispanic patients were significantly more likely to prefer the FOBT and the BE scenarios compared with Withes. African Americans were significantly more likely to prefer the SIG and the Virtual–Colonoscoy  scenarios and less likely to prefer FIT compared with whites. Those with less education were more likely to prefer FOBT than Colonoscopy. Compared to white persons, Hispanics preferred FOBT to endoscopic tests and less likely FIT; African Americans preferred the endoscopic tests to FOBT and FIT.

Fig 3. Table form Hawley et al (2008) , p. 14

In their 2010 paper, Hol, van Leerdam M.E. et al compared three days of gFOBT without dietary restrictions with one day of FIT (OC-Micro) and flexible sigmoidoscopy (FS) in a representative sample of Dutch population (n=15011) randomized by age, gender and SES (using postal code).  High SES and living in a rural area were associated with increased attendance in all screening arms. The age specific participation rate to gFOBT screening was significantly higher in women than in men aged 50-59 years (OR, 1.6; CI, 1.4 to 2.0 while no difference was seen in the other age groups (60-64 years and 65-74 years). Independent predictors for higher participation to Fit screening were female sex and age 60-64 years, while a low participation rate was especially found among men ages 50-55 years (gFOBT, 37% and FIT, 51%).

Birkenfeld et al. (2011) aimed at better understanding if demographic and socioeconomic factors might affect patients compliance with tests uptake. Subject from Israeli population related to Calalit health service and their primary area clinics were clustered according to socioeconomic status (SES), using clinic quarter as a proxy of socio-economical status. Clinics from each SES were then randomly allocated into either the FIT or gFOBT arm. Results showed that age above 60 years and female gender were independent predictors of increased attendance/compliance in both arms.