Concerns are being raised about research done at the University of Western Ontario that concluded egg yolks are almost as bad as smoking when it comes to coronary artery disease.

The paper was released Monday and has attracted international attention, with some scientists saying the results need to be interpreted with caution.

Dr. David Spence tracked the smoking habits and egg consumption of about 1,200 adults and concluded that egg yolks accelerate plaque build-up in arteries, making them almost as bad as smoking for heart disease. Spence said the culprit is high levels of cholesterol found in the yolk.

His paper was published in the medical journal Atherosclerosis.

But Dr. Antonis Zampelos, a professor of human nutrition and the journal's expert on dietary matters, said Spence should have also tracked the intake of saturated fat, which is a proven cause of coronary disease.

"The results are not as strong as the statement that came out," said Zampelos.

"The results lack the greatest validity I would say. I'm not saying that this is not an interesting study," he said. "I'm saying that you can't really make such a strong statement about smoking."

Spence said his only funding came from data collected with the support of the Heart and Stroke Foundation of Canada.

"There is need for more research to fully understand what's going on here," said Christine LeGrand, a science policy analyst for the foundation.

Spence said he's heard the criticism of his research and agrees more information about his patients would have added weight to his research, but he doesn't think the results would have been any different.