Prolonged Nightly Fasting and Breast Cancer Risk: Findings from NHANES (2009-2010)

Cancer Epidemiol Biomarkers Prev. 2015 May;24(5):783-9. doi: 10.1158/1055-9965.EPI-14-1292. Epub 2015 Apr 20.


Background: A novel line of research has emerged, suggesting that daily feeding-fasting schedules that are synchronized with sleep-wake cycles have metabolic implications that are highly relevant to breast cancer. We examined associations of nighttime fasting duration with biomarkers of breast cancer risk among women in the 2009-2010 U.S. National Health and Nutrition Examination Survey.

Methods: Dietary, anthropometric, and 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 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 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, body mass index, total kcal intake, evening kcal intake, and the number of eating episodes per day.

Results: Each 3-hour increase in nighttime fasting (roughly 1 SD) was associated with a 4% lower 2-hour glucose measurement [β, 0.96; 95% confidence interval (CI), 0.93-1.00; P < 0.05], and a nonstatistically significant decrease in HbA1c. 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 < 0.05) and nonsignificantly reduced odds of elevated 2-hour glucose.

Conclusions: A longer nighttime duration was significantly associated with improved glycemic regulation.

Impact: Randomized trials are needed to confirm whether prolonged nighttime fasting could improve biomarkers of glucose control, thereby reducing breast cancer risk.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers / blood*
  • Blood Glucose / metabolism
  • Breast Neoplasms / blood
  • Breast Neoplasms / epidemiology*
  • Circadian Rhythm / physiology
  • Fasting / blood*
  • Female
  • Glycated Hemoglobin / metabolism
  • Health Surveys
  • Humans
  • Middle Aged
  • Nutrition Surveys
  • Risk Factors
  • United States / epidemiology


  • Biomarkers
  • Blood Glucose
  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human