Recent reports have shown that coronary heart disease (CHD) continues to be a leading cause of death among Americans despite a remarkable decline in cardiovascular deaths related to the disease over the past several decades. CHD mortality rates fell by as much as 52% in men and 49% in women between 1980 and 2002, according to some research. However, other data suggests that these beneficial trends may not have been experienced by all demographic groups. “A 2007 study showed that there was a dramatic slowing in the average annual rate of decline of CHD mortality among adults aged 35 to 54,” explains Viola Vaccarino, MD, PhD. “Younger women appeared to be a particularly vulnerable patient group in this analysis.”


Examining Long-Term Trends

For a study published in Circulation, Dr. Vaccarino and colleagues examined CHD mortality rates in the United States by age and sex from 1979 to 2011. “It’s important to assess long-term trends in CHD mortality to monitor our progress and see if more work is needed,” says Dr. Vaccarino.  The study group calculated age-specific CHD mortality rates and compared estimated annual percentage changes (EAPC) during three approximate decades of data: 1979–1989, 1990–1999, and 2000–2011. The authors then used regression modeling to assess EAPC trends over time.

According to the results, the EAPC from 1979 to 2011 was lower in people younger than 55 years of age than in older groups in the two most recent decades. In contrast, CHD mortality rates declined steeply after 2000 for both women and men who were aged 65 and older.


Younger Women at Particular Risk

The study also revealed that the EAPC was lower in women younger than 65 than men in the same age group. Women younger than age 55 had the lowest rate of decline in CHD mortality, with an EAPC of −1.9%. “Women and men aged 55 and younger initially had clear declines in CHD mortality from 1979 until 1989,” Dr. Vaccarino says (Table). “However, we saw these declines flatten over the next two decades.” Younger women had no improvements between 1990 and 1999 with regard to EAPC, and only minimal improvements were observed since 2000.

Findings of the study suggest that previous disparities in CHD mortality declines between young women and men are narrowing due to the fact that young women and men had a similar declining trend in CHD mortality in the most recent decade. However, Dr. Vaccarino says it is important to understand the significance of the recent EAPC being low. In contrast, men and women aged 65 and older have continued to experience large and steady CHD mortality reductions since 2002. This may be an important driver in recent data showing that CHD mortality is dropping overall in the U.S.


Assessing Potential Reasons

Causes of the sluggish improvements in CHD mortality seen among young adults in recent decades are unclear, but worsening risk factors may play a role, according to Dr. Vaccarino. “We need a better understanding of the mechanisms that contribute to the worse risk factor profiles in women in order to improve their future morbidity and mortality,” she says. “This includes preventing and managing conditions like obesity, diabetes, and other risk factors earlier in life. Our data reflect a lack of effective CHD prevention rather than a lack of treatment efficacy for the disease.”

Historically, studies have indicated that there is lower awareness and recognition of CHD in women, although data have indicated that there has been some improvement in recent years. A factor that may be contributing to the slow decline in CHD mortality among young people is that CHD prevention guidelines may disproportionately underestimate risks in younger people, which in turn can undermine prevention efforts.

“Non-traditional social and psychological risk factors for CHD may also play a role in our findings because they are not routinely evaluated or managed,” says Dr. Vaccarino. “For example, psychosocial stress is more common in younger adults, especially women. This can increase the risk of CHD hospitalizations and mortality. It may also delay recovery after cardiac events.”


Looking Forward

According to Dr. Vaccarino, more studies are needed to determine why different trends were seen in CHD mortality among younger patients, especially women. “It will be challenging to further improve mortality rates in this patient population until we pay more attention to prevention strategies for cardiovascular risk factors,” she says. “Clinicians need to be vigilant when caring for younger patients at risk for CHD before the disease manifests. These individuals need to be directed to prevention therapies without delay.”