A study on the trends and prevalence of coronary heart disease (CHD) in Americans 40 years and older has found that rates of CHD have decreased from 10.3 percent in 2001-2002 to 8 percent in 2011-2012.

With many of causes of CHD being preventable, such as smoking and obesity, the researchers studied these trends alongside the prevalence of CHD.

The research was based data from the National Health and Nutrition Examination Survey (NHANES), through a six two-year NHANES survey cycles beginning in 2001 and concluding with 2012, and included results from 21,472 adults 40 years of age or older.

Results of the study included:

• Prevalence of CHD for all adults 40 years of age or older decreased from 10.3 percent to 8.0 percent, but no signs of a significant change in adults ages 40-59.
• Individuals 60 or older also had lower prevalence of CHD, dropping from 19.5 percent in 2001-2002 to 14.9 percent in 2011-2012.
• Women experienced the most significant decrease from 8.5 percent in 2001-2002 to 6.2 percent in 2011-2012.
• CHD also decreased in more racial spaces, including non-Hispanic white and non-Hispanic black adults but showed no change for Mexican American adults.

In the study of the trends of risk factors, there were also some ups and downs:

• Smoking decreased from 2001 to 2012.
• The rate of high blood pressure and abnormal cholesterol has not changed in the last 12 years.
• The control rates of patients with hypertension and hypercholesterolemia increased.
• Obesity and diabetes rates have increased but the control of glucose levels in the general population has improved.

"The decreasing prevalence of CHD (including angina and myocardial infarction) might result from a combination of prevention efforts and improvements in the management of risk factors," wrote lead investigator Sung Sug (Sarah) Yoon, PhD, RN, who was affiliated with the Centers for Disease Control's National Center for Health Statistics, when the study was conducted. "Reasons for a reduction in the prevalence of CHD, angina, and MI in the lower CHD-risk groups could relate to general trends in lifestyle changes, such as improved diet, increased level of physical activity, or other factors such as prophylactic aspirin use among U.S. adults. Furthermore, anti-smoking prevention efforts have resulted in a decreased prevalence of cigarette smoking, which may have contributed to the decrease in CHD prevalence."