The low uptake of breast screening in cities is a major public health issue and may be due to organisational factors: a Census-based record linkage study.

BACKGROUND: Cancer screening uptake is generally lower in UK cities but quantifying city-level effects from causes due to population composition that comprise cities is hampered by data limitations.
METHODS: A unique data linkage project combining a 2001 Census-based longitudinal study in Northern Ireland with the NHS Breast Screening Program. Validated uptake in the three years following the Census for Belfast Metropolitan Urban Area was compared against the rest of the country with adjustment for cohort attributes defined at Census.
RESULTS: Belfast Metropolitan Urban Area contained 34.8% of invited women but a greater proportion who rented their accommodation (40.3%) or who did not have a car (47.1%). After full adjustment for demographic and socio-economic factors, Belfast Metropolitan Urban Area uptake was lower for first and subsequent screen (Odds ratio (OR) 0.72; 95% CIs 0.66, 0.78 and OR 0.58; 95% CIs 0.55, 0.62 respectively). There were no significant interactions between patient characteristics and area of residence indicating that all residents in Belfast Metropolitan Urban Area are equally affected.
CONCLUSION: The reduced uptake of screening in cities is a major public health issue; the effects are large and a large proportion of the population are affected, organisational factors appear to be the primary cause. Strategies to correct this imbalance might help reduce inequalities in health.