Study: Blacks, Women Face Greater Burden From CVD Risk Factors
Diabetes and hypertension play key roles
The impact of major cardiovascular risk factors combined is greater in women than in men and in blacks than in whites. While the gender gap may be narrowing, differences by race may be increasing, according to new research in the American Heart Association journal Circulation.
“We’ve been targeting traditional risk factors in public health campaigns for many years,” said lead author Susan Cheng, MD, MPH. “We wanted to take a look at how well we’ve been doing over time at keeping these risk factors from causing heart and vascular disease — both by preventing the risks from occurring and by minimizing their effects when they do occur.”
Cheng and her colleagues studied population-attributable risk (PAR) changes for the five major modifiable cardiovascular risk factors: high cholesterol, hypertension, smoking, obesity, and diabetes. The PAR measures how common a risk factor is and the degree by which the factor raises the chance of future cardiovascular disease (CVD).
The researchers examined data from 13,541 subjects (56% women and 26% black) in the Atherosclerosis Risk in Communities study. The participants attended examinations during one of four periods (1987–89, 1990–92, 1993–95, or 1996–98) when they were 52 to 66 years old and were free of CVD. The investigators assessed risk factors at these examinations and then calculated the contribution of each factor to the risk of developing CVD over the next 10 years.
Their key findings included the following:
- The combined PAR for the five major risk factors stayed the same in blacks (at 0.67) while falling in whites (from 0.56 to 0.48).
- The contribution of diabetes to CVD was higher in women than in men (most recently, 0.21 vs. 0.14, respectively), and was more than twice as high in blacks than in whites (most recently, 0.28 vs. 0.13, respectively).
- The contribution of hypertension to CVD was higher in women than in men (most recently, 0.32 vs. 0.19, respectively), and higher in blacks than in whites (most recently, 0.36 vs. 0.21, respectively).
- The contribution of obesity to cardiovascular disease stayed at the same level (0.06) over time. The researchers emphasize that, despite comparably lower PAR values, the importance of obesity as a risk factor may be seen in later years and could be through its mediating effect on diabetes.
- The contribution of smoking and high cholesterol appeared to lessen in recent years (dropping from 0.15 to 0.13 for smoking, and from 0.18 to 0.09 for high cholesterol).
“Our results don’t suggest that a risk factor like smoking has become any less dangerous, but that fewer people are smoking,” Cheng said. “In fact, for current smokers the risk of heart and vascular disease has actually gone up, possibly because remaining smokers tend to smoke more heavily or carry additional risk factors.”
Improvements in awareness and treatments for high cholesterol, such as dietary changes and statin therapy, likely account for the lessened effect of that risk factor, the researchers said.
“As we know, statins not only treat cholesterol abnormalities but reduce inflammation and have other protective effects,” Cheng remarked.
The study results highlight the ongoing need for targeted as well as population-based approaches to risk-factor modification, despite progressive improvements in public health efforts to reduce the overall burden of the risk for heart and vascular disease, the researchers said.
Source: AHA; August 11, 2014.