The association between neighborhood socioeconomic status and the risk of incidence and mortality of colorectal cancer: A systematic review and meta-analysis of 1,678,582 participants

Objectives: We conducted a systematic review and meta-analysis to evaluate the association between neighborhood socioeconomic status (n-SES) and the risk of incidence and mortality in colorectal cancer (CRC). Setting: A comprehensive literature search was performed using PubMed/MEDLINE, ISI Web of Science and Scopus without any limitation until October 11, 2023. Inclusion criteria consisted of observational studies in adult subjects (>= 18 years) which provided data on the association between n-SES and CRC-related incidence and mortality. Relative risk (RR) and 95 % confidence interval (CI) were pooled by employing a random-effects model. We employed validated methods to assess study quality and publication bias, utilizing the NewcastleOttawa Scale for quality evaluation, subgroup analysis to find possible sources of heterogeneity, Egger's regression asymmetry and Begg's rank correlation tests for bias detection and sensitivity analysis. Results: Finally, 24 studies (21 cohorts and 3 cross-sectional studies) from seven different countries with 1678,582 participants were included. The analysis suggested that a significant association between lower n-SES and an increased incidence of CRC (RR=1.11; 95 % CI: 1.08, 1.14; I-2=64.4 %; p<0.001; n=46). The analysis also indicated a significant association between lower n-SES and an increased risk of mortality of CRC (RR=1.21; 95 % CI: 1.16, 1.26; I-2=76.4 %; p<0.001; n=23). Furthermore, subgroup analysis revealed that there was a significant association between lower n-SES and an increased risk of incidence of CRC in colon location (RR=1.06; 95 % CI: 1.02, 1.10; I2=0.0 %; p=0.001; n=8), but not rectal location. In addition, subgroup analysis for covariates adjustment suggested that body mass index, smoking, physical activity, alcohol intake, or sex adjustment may influence the relationship between n-SES and the risk of incidence and mortality in CRC. Conclusion: Lower n-SES was found to be a contributing factor to increased incidence and mortality rates associated with CRC, highlighting the substantial negative impacts of lower n-SES on cancer susceptibility and health outcomes.