Understanding Bowel Cancer Screening Intention across different populations: Identifying Predictors of Bowel Screening Interventions

Bowel cancer is the third leading cause of cancer-related mortality globally.
Screening enables early detection and significantly reduces mortality; however,
uptake remains low, particularly among individuals from diverse backgrounds.
Understanding psychosocial determinants of screening and evaluating intervention
strategies is therefore essential to inform effective screening policies.
This mixed-methods PhD thesis aimed to: (1) explore barriers and facilitators of
bowel cancer screening; (2) identify psychological predictors of screening intention
and behaviour; and (3) evaluate the effectiveness of existing screening interventions
to inform effective public health strategies.
The thesis comprised two systematic reviews and two empirical studies. Study 1
used qualitative interviews across India and the UK (N = 30) to explore screening
beliefs, analysed using reflexive thematic analysis. Chapter 4 presented a systematic
review of 84 studies investigating psychosocial predictors of intention and
behaviour. Study 2 was a large cross-sectional survey (N = 2,000) conducted across
India and the UK using Protection Motivation Theory (PMT) constructs. Chapter 6
synthesised 119 studies to evaluate strategies to increase screening uptake.
Study 1 identified key barriers including lack of awareness, negative attitudes
towards healthcare, and socioeconomic constraints, while social support and health
literacy facilitated participation. Chapter 4 found self-efficacy (r = .16), response
efficacy (r = .15), and perceived benefits (r = .18) were the strongest predictors of
intention, while perceived barriers negatively predicted uptake (r = –.12). Study 2
confirmed self-efficacy (β = .31), knowledge (β = .22), and response efficacy (β =
.19) significantly predicted intention. Chapter 6 showed interventions increased
uptake (OR = 1.46, 95% CI [1.32, 1.61]); mailed FIT kits (OR = 2.10) and patient
navigation (OR = 1.84) were most effective, with no significant differences between
White and Non-White groups.
Psychological determinants and structural barriers jointly influence screening
intention. Theoretically grounded interventions improve uptake effectively.