5.4 Small geographic area characteristics and cancer risk

Figure 5.3 Adjusted relative risks (with 95% confidence intervals) of colorectal cancer by socio-economic characteristics of geographic area of residence: males

Males

Among men there was no significant difference in risk of colorectal cancer between RoI and NI when adjusted for age alone. However, after adjustment for age and socio-economic factors colorectal cancer risk was lower in NI than in RoI (RR=0.92, 95%CI=0.89-0.96) (Figure 5.3).

Male colorectal cancer was positively associated with population density, with men resident in the most densely populated areas 14% more likely to develop colorectal cancer than those in the least densely populated areas.

Similarly, unemployment was associated with male colorectal cancer, with a steady increase in risk as unemployment in an area increased.

Colorectal cancer risk was not related to area-based educational attainment.

Persons resident in areas with the highest proportion of persons aged 75 and over living alone had a 10% greater risk of colorectal cancer than those resident in areas with the lowest proportion.

Figure 5.4 Adjusted relative risks (with 95% confidence intervals) of colorectal cancer by socio-economic characteristics of geographic area of residence: females

Females

There was no significant difference between RoI and NI in the risk of colorectal cancer for women when adjusted for age, or when adjusted for age and socio-economic factors (Figure 5.4).

While female colorectal cancer risk was associated with population density, the association was weaker than for men, with the relative risk 4% greater in the most, compared to the least, densely populated areas.

Neither unemployment nor educational attainment was associated with female colorectal cancer risk.

Areas with higher proportions of persons aged 75 and over living alone had a greater risk of female colorectal cancer. This relationship was slightly stronger for women than men.