Multivariable adjusted ORs and 95% confidence intervals of colorectal and colon cancer by median levels of IGF-1, C-peptide, IGF-1/IGFBP3 ratio and vitamin D, HPFS and NHS combined.

*Low: below median level; high: equal or above median level.$Multivariable adjusted for matching factors (age, year and month of blood donation), body mass index (kg/m2, continuous), pack-years of smoking (continuous), physical activity (MET-hr week, continuous), intake of alcohol, methionine, folate, retinol, red and processed meat, calcium (all intake covariates as continuous variables), family history of colorectal cancer (yes vs. no), sex, fasting status (0–2, 3–4, 5–8, ≥9 hours since last meal), aspirin use (†Models for C-Peptide only included participants without self-reported diabetes mellitus.‡‡Abbreviations: IA = interaction, AP = attributable proportion due to interaction, RERI = relative excess risk due to interaction, RR11 = relative risk among those exposed to both risk factor #1 and risk factor #2, RR10 = relative risk among those exposed to risk factor #1 but not risk factor #2, RR01 = relative risk among those exposed to risk factor #2 but not risk factor #1AP = RERI / RR11 ( = 0 if no interaction) with RERI = RR11 - RR10 - RR01 + 1 ( = 0 if no interaction)