Background: A growing body of research has demonstrated that individuals who live in neighborhoods with more severe socioeconomic deprivation may have higher risks for colorectal cancer (CRC). However, previous studies have examined neighborhood socioeconomic status (SES) at only 1 point in time, and it is unclear whether changes in neighborhood SES also can influence the risks of CRC.
Methods: Cox regression analysis was used to examine different trajectories of change in neighborhood SES over 10 years in relation to the incidence of CRC among 266,804 participants (ages 51-70 years) in the National Institutes of Health-AARP Diet and Health Study. Eligible participants reported living in the same neighborhood at baseline (1995-1996) and from 2004 to 2006 according to a follow-up questionnaire. Changes in neighborhood SES were measured between 1990 and 2000 by SES indices derived from Census data. Neighborhoods were grouped into 4 categories based on median SES indices in 1990 and 2000 (low-low, low-high, high-low, and high-high).
Results: Compared with residents whose neighborhoods were in the higher SES group at both time points (reference category), those whose neighborhoods were consistently in the low SES group had a 7% higher risk of developing CRC (hazard ratio, 1.07; 95% confidence interval, 1.00-1.14). Moreover, the risk of CRC was 15% higher (hazard ratio, 1.15; 95% confidence interval, 1.02-1.28) for those living in neighborhoods with decreasing SES (high-low) over time.
Conclusions: The current findings suggest that exposure to consistently low SES neighborhoods and/or a decrease in neighborhood SES over a period of time may be associated with higher risks of CRC.
Keywords: cancer risk; colon cancer; long-term trajectory; neighborhood socioeconomic status; rectal cancer.
© 2018 American Cancer Society.