Abstract A29: Frequency and circadian timing of eating may influence metabolic risk of breast cancer
Authors: Marinac Catherine R. , Sears Dorothy D. , Gallo Linda C. , Natarajan Loki , Breen Caitlin , Patterson Ruth E. 
Published: May 2016

Abstract
Emerging evidence suggests that there is interplay between the frequency and circadian timing of eating and metabolic health. We examined the associations of eating frequency and timing with metabolic and inflammatory biomarkers putatively associated with breast cancer risk. We used data from a nationally representative sample of adult women participating in the National Health and Nutrition Examination 2009-2010 Survey.
Eating frequency and timing variables were calculated from 24-hour food records and included (1) proportion of calories consumed in the evening (between 17.00-00.00h), (2) nighttime fasting duration, and (3) number of eating episodes per day. Multivariable linear regression models examined each eating frequency and timing exposure variable with hsCRP concentrations and the homeostatic model assessment of insulin resistance (HOMA-IR). Logistic regression modeled associations of these same exposure variables with odds of elevated hsCRP (defined as≥ 1.0 mg/L). Models were adjusted for age, education, race/ethnicity, BMI, sleep duration, and caloric intake. Sample weights were used to account for differential probabilities of selection into the sample, nonresponse, and noncoverage. Standard errors were estimated using Taylor Series Linearization.
Dietary, anthropometric and high-sensitivity C-reactive protein (hsCRP) data were available for 2,212 women, and fasting glucose and insulin concentrations (i.e., HOMA-IR) were available for 1,066 women. The mean age of women in this sample was 46.8 (SEM=0.66) years. They consumed an average of 43.1% (SEM=0.62) of daily energy intake between 17.00-0.00h, fasted 12.4 (SEM=0.08) hours per night, and ate 4.7 (SEM=0.05) times per day. Evening caloric intake and eating frequency were significantly associated with hsCRP. Specifically, a 10% increase in the proportion of calories consumed in the evening was associated with a 1.02-unit increase in hsCRP (β 1.02; p&lt;.05) and a 7% higher odds of elevated hsCRP (OR 1.07; 95% CI: 1.01-1.14). Conversely, eating one additional meal or snack per day was associated with a reduction in hsCRP (β 0.94; p&lt;.05); however the associations of eating frequency and odds of elevated hsCRP were not statistically significant (OR 0.91; 95% CI: 0.81-1.03). No associations were found between nighttime fasting duration and hsCRP. The direction, magnitude, and significance of these associations were maintained when all three exposures were modeled together. None of the eating frequency and timing variables were significantly associated with HOMA-IR values.
These findings suggest that eating more frequently and reducing evening energy intake may lower generalized inflammation in the body and subsequently reduce breast cancer risk. Randomized trials are needed to validate these associations.
Citation Format: Catherine R. Marinac, Dorothy D. Sears, Linda C. Gallo, Loki Natarajan, Caitlin Breen, Ruth E. Patterson. Frequency and circadian timing of eating may influence metabolic risk of breast cancer. [abstract]. In: Proceedings of the AACR Special Conference: Metabolism and Cancer; Jun 7-10, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(1_Suppl):Abstract nr A29.