Video: Why does Washington have the highest breast cancer rate?

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Washington State is in the middle of a medical mystery. Why does our state have the highest rate of breast cancer in the country? While the evidence isn't conclusive yet, there are clues.

First: wine, the beverage that may help prevent heart disease can cause breast cancer.

"We know that women who drink alcohol at moderate levels are more at an increased level of getting breast cancer. That's really been consistently shown," said Dr. Anne McTiernan, Fred Hutchinson Cancer Research Center.

Alcohol consumption in our state is slightly higher than the national average. It's something to consider when investigating why we have the nation's highest incidence of breast cancer, but there are other culprits on the short list.

"One that comes to mind that has been well studied here is hormone replacement therapy," said Kathi Malone, epidemiologist at Fred Hutchinson Cancer Research Center.

Before hormone replacement therapy was deemed dangerous, it was widely used by urban women in Washington.Experts speculate we are still seeing the effects. Also due to affluence and education in our state, women opt to have children later in life.

"So woman here tend to have their first live births at a later age," said Malone, "so this whole reproductive profile in a region can be different than other regions, say, in the Midwest."

Having children late, or not at all, and not breastfeeding are known to increase a woman's risk of breast cancer. But the good news is that fewer women here are dying from breast cancer. Washington has one of the highest survival rates in the country.