Abstract 1874: Prolonged nightly fasting and breast cancer risk: findings from NHANES (2009-2010)
Authors: Marinac Catherine R. , Natarajan Loki , Sears Dorothy D. , Gallo Linda C. , Hartman Sheri J. , Arredondo Elva , Patterson Ruth E. 
Published: August 2015

Abstract
A novel line of research has emerged suggesting that daily feeding-fasting schedules have metabolic implications that are highly relevant to breast cancer. In rodents, a habitual daily fasting schedule that is aligned with sleep-wake cycles appears to have favorable effects on a variety of cancer risk factors and may reduce cell proliferation. While data from rodent models are compelling, no human studies have explored the potential impact of this type of fasting schedule on cancer risk factors such as hyperglycemia (a possible facilitator of neoplastic proliferation). We examined cross-sectional associations of nighttime fasting duration with glycemic control biomarkers associated with increased breast cancer risk in a population-based sample of women in the 2009-2010 U.S. National Health and Nutrition Examination Survey.
Dietary, anthropometric and glycosylated hemoglobin (HbA1c) data were available for 2,212 women, and 2-hour postprandial glucose concentrations were available for 1,066 women. Nighttime fasting duration was calculated using time-stamped 24-hour food records. Separate linear regression models examined associations of nighttime fasting with HbA1c and 2-hour glucose concentrations. Logistic regression modeled associations of nighttime fasting duration with elevated HbA1c (HbA1c ≥ 39 mmol/mol or 5.7%) and elevated 2-hour glucose (glucose ≥ 140 mg/dL). All models adjusted for age, education, race/ethnicity, BMI, total kcal intake, evening kcal intake, and the number of eating episodes per day. All analyses used sample weights to account for differential probabilities of selection into the sample, nonresponse, and noncoverage. Standard errors were estimated using Taylor Series Linearization.
Women in this sample were an average of 46.8 years of age (SE = 0.66) and fasted approximately 12.4 (SE = 0.08) hours per night. Each 3-hour increase in nighttime fasting (roughly one standard deviation) was associated with a 4% lower 2-hour postprandial glucose measurement (β 0.96, 95% CI 0.93 - 1.00; p&lt;0.05), and a non-statistically significant 0.4 unit decrease in HbA1c (β -0.39, 95% CI -0.84 - -0.05; p = 0.08). Logistic regression models indicate that each 3-hour increase in nighttime fasting duration was associated with roughly a 20% reduced odds of elevated HbA1c (OR 0.81, 95% CI 0.68, 0.97; p&lt;0.05) and non-significantly reduced odds of elevated 2-hour glucose (OR 0.78, 95%CI 0.53-1.54).
Randomized trials are needed to confirm whether a prolonged nighttime fasting schedule could improve biomarkers of glycemic control, thereby reducing breast cancer risk among women.
Citation Format: Catherine R. Marinac, Loki Natarajan, Dorothy D. Sears, Linda C. Gallo, Sheri J. Hartman, Elva Arredondo, Ruth E. Patterson. Prolonged nightly fasting and breast cancer risk: findings from NHANES (2009-2010). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1874. doi:10.1158/1538-7445.AM2015-1874