Night-Shift Work Duration and Risk of Colorectal Cancer According to IRS1 and IRS2 Expression.

ABSTRACT:

Background

We hypothesized that the risk of colorectal cancer in night-shift workers might be different according to insulin receptor substrate status.

Methods

Among 77,470 eligible women having night work assessed in the Nurses' Health Study, we documented a total of 1,397 colorectal cancer cases, of which 304 or 308 had available data on IRS1 and IRS2, respectively. We used duplication-method Cox proportional hazards regression analysis for competing risks to calculate HRs and 95% confidence intervals (CI) for each colorectal cancer subtype. We measured tumor IRS1 or IRS2 expression by immunohistochemistry (IHC).

Results

Compared with women who never worked night shifts, those working ?15 years night shifts had a marginal trend of increased overall risk of colorectal cancer (P _trend = 0.06; multivariable HR = 1.20; 95% CI, 0.99-1.45). Longer duration of night-shift work was associated with a higher risk of IRS2-positive tumors (multivariable HR = 2.69; 95% CI, 1.48-4.89; P _trend = 0.001, ?15 years night shifts vs. never) but not with IRS2-negative tumors (multivariable HR = 0.90; 95% CI, 0.54-1.51; P _trend = 0.72; P _{heterogeneity} for IRS2 = 0.008). Similarly, the corresponding multivariable HRs were 1.81 for IRS1-positive tumors (95% CI, 0.94-3.48; P _trend = 0.06) and 1.13 for IRS1-negative tumors (95% CI, 0.71-1.80; P _trend = 0.56; P _{heterogeneity} for IRS1 = 0.02).

Conclusions

Our molecular pathologic epidemiology data suggest a potential role of IRS in mediating carcinogenesis induced by night-shift work.

Impact

Although these findings need validation, rotating night shift might increase colorectal cancer risk in women with abnormal insulin receptor pathways.

SUBMITTER: Shi Y 

PROVIDER: S-EPMC6954315 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature