Table 3.
Association between neighborhood deprivation, education, and incidence of colorectal cancer explained by behavioral factors and body mass index, NIH-AARP Study, 1995–2006
| Percentage of the association between SES and colorectal cancer risk explained (95% CI) | ||||
| Mediators according to SES measure | Any colorectal cancer | Rectal cancers | Left colon cancers | Right colon cancers |
| Educational level | ||||
| Referent Model* | 1.00 (referent) | 1.00 (referent) | 1.00 (referent) | 1.00 (referent) |
| Separate effects of each factor† | ||||
| Effect of smoking history | 12.9 (9.6 to 41.2) | 8.8 (5.3 to 13.2) | 7.7 (3.9 to 13.2) | 28.0 (14.0 to 100) |
| Effect of Mediterranean diet score | 21.6 (16.4 to 28.9) | 13.8 (9.1 to 20.6) | 17.9 (11.3 to 27.3) | 45.6 (23.4 to 100) |
| Effect of physical activity | 11.9 (8.3 to 17.2) | 4.9 (1.0 to 9.2) | 11.2 (6.1 to 19.2) | 26.7 (11.6 to 95.0) |
| Effect of body mass index (BMI) | 11.3 (8.2 to 14.9) | 3.2 (0.6 to 6.3) | 12.0 (8.0 to 18.7) | 28.0 (13.2 to 95.5) |
| Combined effect of all health behaviors | 37.3 (29.9 to 49.8) | 22.7 (13.9 to 31.4) | 30.3 (21.1 to 48.9) | 78.9 (40.1 to 100) |
| Combined effect of all health behaviors and BMI | 43.9 (35.1 to 57.9) | 24.2 (16.4 to 34.1) | 37.8 (26.3 to 54.6) | 95.0 (50.1 to 100) |
| Neighborhood SES | ||||
| Referent Model* | 1.00 (referent) | 1.00 (referent) | 1.00 (referent) | 1.00 (referent) |
| Separate effects of each factor† | ||||
| Effect of smoking history | 8.6 (6.0 to 12.7) | 5.3 (2.6 to 8.8) | 5.3 (1.6 to 11.7) | 18.3 (8.3 to 100) |
| Effect of Mediterranean diet score | 15.3 (11.1 to 21.9) | 9.9 (6.7 to 16.3) | 14.9 (8.9 to 27.5) | 28.6 (13.2 to 100) |
| Effect of physical activity | 10.7 (7.8 to 15.4) | 4.8 (1.7 to 8.7) | 11.7 (6.3 to 22.7) | 21.2 (8.1 to 96.8) |
| Effect of BMI | 14.7 (10.7 to 22.1) | 4.4 (1.4 to 8.6) | 16.9 (10.4 to 30.4) | 34.6 (16.7 to 100) |
| Combined effect of all health behaviors | 26.4 (20.2 to 37.5) | 15.3 (10.0 to 23.7) | 24.6 (16.1 to 50.3) | 51.3 (23.8 to 100) |
| Combined effect of all health behaviors and BMI | 36.2 (28.0 to 51.2) | 17.6 (11.5 to 27.5) | 36.2 (23.3 to 67.6) | 75.4 (36.5 to 100) |
* Referent models (separately for self-reported education and neighborhood SES) were adjusted for age, sex, race and ethnicity, family history of colorectal cancer, and state of residence, which were entered as categorical variables in the models except age (continuous, measured from the baseline date). Models on the effects of each behavioral factor or BMI (kg/m2) added the respective variable to the referent model.
† Health behaviors refer to Mediterranean diet score, physical activity, and smoking.