Childhood socioeconomic status, healthy lifestyle, and colon cancer risk in a cohort of U.S. women.

Colon cancer is the third most common cancer in the US. While the socioeconomic status -health gradient has been established, findings linking adult socioeconomic status to colon cancer incidence specifically are mixed. Considering childhood socioeconomic status (CSES) and relevant risk factors, including related lifestyle behaviors, may provide more insight. At baseline in 1976, women from the Nurses' Health Study reported CSES as defined by parents' occupation when participants were age 16. Lifestyle-related factors (i.e., physical activity, body mass index, diet, alcohol, and tobacco consumption) were self-reported in 1988 or 1990, and every 4 years thereafter until 2016. Cox regression models estimated hazards ratio (HR) and 95% confidence intervals (CIs) of adopting an unhealthy lifestyle (N = 22,507) and developing colon cancer (N = 100,921) between 1976 and 2016, separately, across parents' occupation levels. During follow-up, 2342 cases of colon cancer occurred. Compared to women whose parents were white collar workers, women whose parents were farmers had lower colon cancer risk (HR = 0.84; 95%CI: 0.72, 0.98), but no differences were evident for women whose parents were blue collar workers in models adjusting for age and familial history of colon cancer. Using the same comparison group, risk of adopting an unhealthy lifestyle over follow-up was not significantly different in women with farmer parents (HR = 0.96, 95% CI: 0.91, 1.02), while children of blue collar workers had slightly greater risk (HR = 1.07; 95%CI: 1.03, 1.12) in age-adjusted models. These findings suggest the impact of CSES on colon cancer risk is modest and varies across outcomes and occupational status.