C-Reactive Protein Level is Linked to Heart Disease Risk Factors in Older Women

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Greenfield JR, Samaras K, Jenkins AB, et al.: Obesity is an important determinant of baseline serum c-reactive protein concentration in monozygotic twins, independent of genetic influences. Circulation109:3022-3028, 2004.

What is the problem and what is known about it so far?

C-reactive protein (CRP) is a protein in the blood. CRP levels rise with inflammation of the blood vessels. Such inflammation is linked to heart disease. High CRP levels have been liked to type 2 diabetes.

Heart disease risk factors include obesity, large waist size, high blood pressure, and high levels of fat in the blood. These are also risk factors for type 2 diabetes.

In this study, researchers asked if high CRP levels are linked to these risk factors. If so, high CRP levels may predict future heart attacks and other heart problems.

Who was studied?

A total of 194 healthy female identical twins. Most had already gone through menopause. The average age was 57.2 years. All women were white.

How was the study done?

Participants were measured for total body fat, waist size, and blood pressure. Levels of CRP and fat in the blood were measured.

Participants were asked if they used hormone replacement therapy (HRT, a common therapy for menopause). They were also asked if they smoked or drank alcohol.

Researchers compared results between identical twins.

What did the researchers find?

Women with higher CRP levels were more likely to have heart problems.

CRP levels were lower in social drinkers (people who drink occasionally but not every day) than in those who didn’t drink and heavy drinkers.

CRP levels were similar in smokers and nonsmokers. They were also similar in heavy and light smokers.

Women on HRT had higher levels of CRP than women not on HRT.

Women with higher diastolic blood pressure (a measure of pressure when the heart is relaxed and filling) had higher CRP levels.

Twins with larger waist size and total body fat had higher CRP levels. Twins with worse levels of fat in the blood had higher CRP levels.

What were the limitations of the study?

The results may not apply to younger women, men, or patients who already have type 2 diabetes or heart disease.

What are the implications of the study?

Keeping track of CRP levels may be important in predicting and preventing future heart problems and type 2 diabetes.