Consumption of sugar-sweetened and artificially sweetened beverages and breast cancer survival.

BACKGROUND: The activation of insulin pathways is hypothesized to promote tumor growth and worsen breast cancer survival. Sugar-sweetened beverages (SSBs) can lead to a higher risk of insulin resistance and may affect survival. The authors prospectively evaluated the relation of postdiagnostic SSB and artificially sweetened beverage (ASB) consumption with mortality among women with breast cancer. METHODS: In total, 8863 women with stage I through III breast cancer were identified during follow-up of the Nurses' Health Study (NHS; 1980-2010) and Nurses' Health Study II (NHSII; 1991-2011). Women completed a validated food frequency questionnaire every 4 years after diagnosis and were followed until death or the end of follow-up (2014 for the NHS and 2015 for the NHSII). Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of breast cancer-specific and all-cause mortality after adjusting for measures of adiposity and other potential predictors of cancer survival. RESULTS: With a median follow-up of 11.5 years, 2482 deaths were prospectively documented, including 1050 deaths from breast cancer. Compared with women who had no consumption, women who had SSB consumption after diagnosis had higher breast cancer-specific mortality (>1 to 3 servings per week: HR, 1.31 [95% CI, 1.09-1.58]; >3 servings per week: HR, 1.35 [95% CI, 1.12-1.62]; Ptrend = .001) and all-cause mortality (>1 to 3 servings per week: HR, 1.21 [95% CI, 1.07-1.37]; >3 servings per week: HR, 1.28 [95% CI, 1.13-1.45]; Ptrend = .0001). In contrast, ASB consumption was not associated with higher breast cancer-specific or all-cause mortality. Furthermore, replacing 1 serving per day of SSB consumption with 1 serving per day of ASB consumption was not associated with a lower risk of mortality. CONCLUSIONS: Higher postdiagnostic SSB consumption among breast cancer survivors was associated with higher breast cancer-specific mortality and death from all causes.