When You Eat Is As Important As What You Eat

Male health professionals who said they regularly skipped breakfast were 27% more likely to die during 16 years of follow-up, according to Leah Cahill, PhD, of the Harvard School of Public Health in Boston, and colleagues, who adjusted for diet, demographics, physical activity, television watching, and amount of sleep.

And those who said they ate late at night were 55% more likely to die.

Both relationships, however, fell shy of statistical significance after further adjustment for body mass index, hypertension, hypercholesterolemia, and diabetes, "suggesting that eating habits may affect risk of coronary heart disease through pathways associated with these traditional risk factors," they reported online in Circulation: Journal of the American Heart Association.

The results should be validated in other studies, the researchers said.

"If replicated in women and other ethno-cultural groups, the findings from the present study provide evidence to support a recommendation of daily breakfast eating by clinicians and health authorities to prevent coronary heart disease and to improve health at both the individual and population levels," they wrote.

"There's lots of things we know that we can do to reduce our coronary heart disease risk," said co-author Eric Rimm, ScD, in an interview. "This is a cheap one, it's a simple message, [and] it can be part of any primary care provider's message to a patient."

In a scientific statement from the American Heart Association in 2012, researchers outlined effective population approaches to improve dietary habits. In 2013, the heart organization updated its guide for improving cardiovascular health at the community level.

Previous studies have demonstrated associations between skipping meals and excess weight, dyslipidemia, hypertension, insulin resistance, and diabetes, but a possible association with coronary heart disease had not been explored.

Cahill and colleagues examined the relationship between coronary heart disease risk and skipping breakfast and other eating habits using data from the Health Professionals Follow-Up Study (HPFS), an ongoing investigation of male health professionals.

The current analysis included 26,902 men ages 45 to 82 who were free from cardiovascular disease and cancer in 1992, which served as baseline. At that point, 13% reported not eating breakfast and 0.2% said they ate late at night.

Through follow-up, there were 1,527 incident cases of coronary heart disease, defined as nonfatal MI or fatal coronary heart disease.

The relationships between coronary heart disease and both skipping breakfast and eating late at night became nonsignificant after adjustment for potential mediators -- RR 1.18 (95% CI 0.98-1.43) for skipping breakfast and RR 1.41 (95% CI 0.95-2.08) for late-night eating.

"However," the authors noted, "we were underpowered with cases for a detailed mediation analysis, especially for late-night eating."

"The late-night eaters in our study represented only a small percentage of the HPFS population, and too few other population studies have reported the frequency of late-night eating for an accurate assessment of whether late-night eating is a common habit," they wrote. "Therefore, it remains unknown whether the association that we observed between late-night eating and risk of coronary heart disease is relevant as a public health concern."

The number of times the men ate per day was not associated with the risk of coronary heart disease, even though previous analyses of this cohort have shown relationships between eating frequency and weight gain and type 2 diabetes.

Cahill and colleagues acknowledged several limitations of the study, including the lack of information on circadian rhythms and exposure to light and dark; the low rate of working night shifts, which precluded an assessment of the influence of shift work; the inclusion of data on regular eating habits only; and the study's nearly all-white population. In addition, eating habits were assessed at one point only and that information was not accompanied by the specific nutrient composition of meals and snacks.

"Future studies to confirm our findings are necessary, as are studies of other cardiovascular outcomes such as hypertension and stroke that may have modestly different etiologic pathways," the researchers wrote.

For information on secondary prevention and risk reduction for cardiac and vascular diseasesee these guidelines from the American Heart Association.