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Early dinner associated with reduced risk for prostate, breast cancer

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July 17, 2018

People who ate their evening meal before 9 p.m. or left a 2-hour window between eating dinner and going to bed had a 20% lower risk for breast or prostate cancer than those who ate after 10 p.m. or went to bed fewer than 2 hours after eating, according to findings published in International Journal of Cancer.

“We assessed in a large population-based study in Spain whether timing of eating and sleep patterns are associated with breast and prostate cancer risk, the two most common night shift-related cancers in humans,” Manolis Kogevinas, MD, PhD, research professor at Barcelona Institute for Global Health in Spain, and colleagues wrote. “We also evaluated whether circadian timing of meals modies the effect of factors associated with cancer risk, such as adherence to cancer prevention recommendations.”

The findings were part of the MCC-Spain project, a population-based case-control study of patients with five types of tumors and controls from 12 regions in Spain performed between 2008 and 2013. Kogevinas and colleagues compared 1,205 patients with breast cancer and 621 patients with prostate cancer with 1,321 women and 872 men recruited as healthy controls matched by age and sex, with an age range of 20 to 85 years. No participants had ever worked night shifts.

Participants filled out a Food Frequency Questionnaire and provided information on timing of their meals, as well as sleep schedules and chronotypes. Kogevinas and colleagues also evaluated participants’ adherence to World Cancer Research Fund/American Institute of Cancer Research recommendations for cancer prevention.

Participants who went to bed 2 hours or more after eating their evening meal had a 20% lower risk for breast and prostate cancer combined than those who went to sleep immediately after eating (OR = 0.8; 95% CI, 0.67-0.96). These participants also had a lower risk for each cancer individually (prostate cancer, OR = 0.74; 95% CI, 0.55-0.99; breast cancer, OR = 0.84; 95% CI, 0.67-1.06).

This effect also occurred among patients who ate dinner before 9 p.m., compared with those who ate dinner after 10 p.m., for both cancers (OR = 0.82; 95%, 0.67-1), an effect that appeared slightly more pronounced for prostate cancer (OR = 0.75; 95% CI, 0.53-1.07) than breast cancer (OR = 0.85; 95% CI, 0.66-1.09).

The protection offered by a longer interval between supper and sleep appeared more pronounced among participants who adhered to cancer prevention recommendations (OR for both cancers = 0.65; 95% CI, 0.44-0.97), as well as in those who were described as “morning types” (OR both for cancers = 0.66, 95% CI, 0.49-0.9).

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“Our study concludes that adherence to diurnal eating patterns is associated with a lower risk of cancer,” Kogevinas said in a press release.

High adherence to cancer prevention policies also had a protective effect for breast cancer (OR = 0.84; 95% CI, 0.67-1.04) compared with low adherence, but less so for prostate cancer (OR = 0.9; 95% CI, 0.66-1.25). The association between time elapsed between eating and sleep for both cancers appeared more pronounced among individuals who adhered to cancer prevention recommendations (OR = 0.65; 95% CI, 0.44-0.97).

The researchers wrote that “adherence to a more diurnal eating pattern, and specifically an early supper and a long interval between last meal and sleep, were associated with a lower breast and prostate cancer risk, stressing the importance of evaluating circadian rhythms in diet and cancer studies and revisiting recommendations for prevention.” – by Andy Polhamus

Disclosures: The authors report no relevant financial disclosures.

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This report by Kogevinas and colleagues is an interesting contribution to the literature about circadian rhythms and cancer. Previous data have linked nighttime light exposure and shift work to increased risk for breast cancer, among other adverse health consequences. Li and colleagues have shown shift work in young physicians correlates with changes in the diurnal cortisol pattern and higher waking cortisol values. The Nurses’ Health Study demonstrates a relationship for rectal cancer but not colon cancer, whereas a large French population-based study links shift work to aggressive prostate cancer only when shift work continues for several decades.

More recently, the variations in duration of fasting and timing of meals have been linked to cancer risk. Prolonged nighttime fasting has been linked to decreased glucose, decreased hemoglobin A1c, decreased inflammation and decreased breast cancer risk in NHANES data for 2009-2010.

In the current analysis, Kogevinas and colleagues performed a case-control study with 1,205 breast cancer cases and 621 prostate cancer cases among Spanish individuals who had never done night work. Comparing these patients with healthy controls, cancer risk decreased with an increasing interval from the evening meal to sleep, with the effect more pronounced for prostate cancer than for breast cancer. There was a nonsignificant association between short interval between the evening meal and nulliparity for women, in a cohort with fewer than 20% nulliparous participants. Appropriately controlling the data for indoor light exposure, blue spectrum light and duration of sleep did not significantly alter the findings; however, a key variable of interest — in light of the NHANES data — that was not reported was the overall duration of nighttime fasting.

This study provides further evidence for the diversity of diurnal differences to be considered when studying circadian health effects.

References:

Li J, et al. J Occup Med Toxicol. 2018;doi:10.1186/s12995-018-0204-y.

Marinac CR, et al. Cancer Epidemiol Biomarkers Prev. 2015;doi:10.1158/1055-9965.EPI-14-1292.

Marinac CR, et al. PLoS One. 2015;doi:10.1371/journal.pone.0136240.

Barbara A. Burtness, MD

HemOnc Today Editorial Board Member

Yale Cancer Center

Disclosure: Burtness reports no relevant financial disclosures.