“SWEET DREAMS ARE MADE OF THIS*” CONSUMPTION OF SUGAR-SWEETENED DRINKS IMPACTS BREAST CANCER SURVIVAL
*Recorded and written by the Eurythmics (Annie Lennox and Dave Stewart)
The American diet is rich in sugar-sweetened beverages (SSB) such as soft drinks, fruit-flavored drinks, punches, sports drinks, and energy drinks. The authors of this study (Farvid et al.) theorized that SSBs might impact the prognosis of women diagnosed with breast cancer. A recent study by these authors strengthened their hypothesis. The study, utilizing subjects from the Nurses Health Study (NHS) and the Nurses Health Study II (NHSII), found that fruit juice and high glycemic diet were associated with breast-cancer specific and all-cause mortality. Consequently, the researchers studied the association between SSB and artificially sweetened beverages (ASB) after the diagnosis of breast cancer with breast cancer-specific and all-cause mortality.
The NHS and NHSII is an ongoing prospective cohort study beginning in 1976 and enrolling over 200,000 female nurses in the United States. This study mainly focused on those nurses thoroughly completing the food frequency questionnaire (FFQ) and who had developed breast cancer. The questionnaire also included information on the post-diagnostic body mass index, physical activity, smoking status, and aspirin use.
All FFQs were updated every 2 to 4 years. During a median follow-up of 11.5 years, 8863 eligible women were diagnosed with breast cancer. Post diagnostic SSB consumption was associated with a higher breast cancer-specific mortality. The HR for breast cancer-specific mortality was 1.31 for 1 to 3 servings per week and 1.35 for greater than three servings per week. Among women who drank greater than three servings per week of SSBs after being diagnosed with breast cancer, there were 56.3 additional deaths per 10,000 person-years of follow-up compared with women who did not drink SSBs. The proportional reduction expected in breast cancer-specific mortality was 10.5% if all women did not drink SSBs after diagnosis and was 8.6% if all women consumed less than two servings per month SSBs after diagnosis.
Mortality did not differ substantially by consumption of post-diagnostic carbonated and noncarbonated SSBs. Both caffeinated and non-caffeinated soft drinks were associated with all-cause mortality risk. However, replacing one serving per day of SSB consumption within an iso-volumetric serving of coffee or tea was associated with an 18% and 15% lower risk of breast cancer-specific mortality, respectively. The findings were similar for all-cause mortality.
In conclusion, this very large prospective study demonstrated that higher SSB consumption after breast cancer diagnosis was associated with breast cancer-specific and overall mortality risk among breast cancer survivors. Higher ASB consumption, in contrast, was not associated with higher breast cancer-specific or all-cause mortality among women who had previously been diagnosed with breast cancer.