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 Newcastle-Ottawa 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; I2=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; I2=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.