Nearly 16 years ago, a co-worker of mine at the San Jose Mercury News was found dead in the back of her car. She had been shot in the head by her estranged husband. I remember being confused upon hearing the news and not quite believing what had happened. Luci Houston, who was 43 at the time, was a name I always associated with joy. She was a gifted photographer, and some of her best work involved capturing emotions, some obvious and some not, at weddings in Silicon Valley.

It was unthinkable to most of us who knew her that she could be killed by someone she loved. But sadly, each year, many American women are killed by intimate partners in similar incidents.

A report out Thursday by the Centers for Disease Control and Prevention about homicides and women provides some disturbing numbers about just how common this is. Homicide is the fifth leading cause of death for women ages 18 to 44. In 2015 alone, 3,519 women and girls were killed. More than half of these killings were perpetrated by current or former boyfriends, husbands or other intimate partners.

Women who are racial and ethnic minorities were disproportionately affected. According to the study, black women had the highest rate of dying by homicide, 4.4 per 100,000, followed by American Indian women at 4.3 per 100,000, Hispanic women at 1.8 per 100,000, white women at 1.5 per 100,000 and Asian women at 1.2 per 100,000.

The data also includes important information about what led to the attacks: In 29.7 percent of homicides related to intimate partners, there was some sort of argument before the victim's death and about 12 percent were associated with jealousy. About 10 percent of the women had experienced violence in the month preceding their death.

Then there is the question of pregnancy. Among women who were killed by intimate partners and were of reproductive age, about 15 percent were pregnant. The report notes that this might or might not be higher than the general U.S. female population and that it requires “further examination.” Previous studies have shown that murder is one of the top causes of death for pregnant women.

The CDC earlier this year launched an effort to stop these deaths by trying to focus on when these relationships begin to go wrong. It starts with the recognition of what public health officials and researchers call intimate-partner violence and police might refer to as domestic violence.

Calling it a “serious, preventable public-health problem that affects millions of Americans,” the CDC emphasizes that it can happen across a life span from when people start dating in their teens to old age. According to data from the National Intimate Partner and Sexual Violence Survey, nearly 1 in 4 adult women and about 1 in 7 men in the United States report having experienced some kind of severe physical violence at the hands of an intimate partner, such as being kicked, beaten or choked.

The CDC has outlined steps that can be taken by local governments, businesses and communities to prevent such assaults. Strategies range from preventing childhood violence, which can lead to adults being violent, to educating potential bystanders on how to intervene and creating “protective environments” in schools and workplaces so that women who are victims can feel safe to seek help.

One of the main takeaways of the new CDC report is the idea that violence should be thought of as a health issue and that homicide is “the most severe health outcome of violence against women.”

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