Attention to Cardiovascular Health Metrics Reduces CVD

An analysis of data from the National Health and Nutrition Examination Survey (NHANES) has concluded that smoking, blood pressure, blood glucose level, diet, and physical activity are all closely linked with all-cause, cardiovascular disease (CVD) and ischemic heart disease (IHD) mortality risk. The findings were reported online in the Journal of the American Medical Association [doi:10.1001/jama.2012.339].

The research focused on 7 cardiovascular health metrics recently recommended by the American Heart Association with the aim of improving cardiovascular health and reducing CVD mortality risk. These include not smoking; being physically active; having normal blood pressure, blood glucose, total cholesterol levels, and weight; and eating a healthy diet.

The nationally representative sample population included 44,959 US adults ≥20 years of age. The analysis included data from NHANES 1988-1994, 1999-2004, and 2005-1010, and the NHANES III Linked Mortality File through 2006.

Notable changes in cardiovascular health metrics from NHANES III 1988-1994 to NHANES 1999-2010 included declines in smoking, individuals eating a healthy diet, individuals having a body mass index of <25, and individuals with a fasting glucose level of <100 mg/dL. The prevalence of participants meeting metrics for total cholesterol level (< 200 mg/dL) and blood pressure (<120 mm Hg/<80 mm Hg) was unchanged between the 2 analysis periods.

Fewer than 2% of individuals included in the analysis met all 7 cardiovascular health metrics. Between NHANES 1988-1994 and NHANES 2005-2010, the prevalence of meeting ≥6 metrics declined from 10.3% to 8.8%. Meanwhile, the prevalence of meeting ≤1 metrics increased from 7.2% to 8.8%. Participants who were younger, women, non-Hispanic whites, and those with a higher level of education were more likely to meet a greater number of metrics.

The cardiovascular health metrics most closely linked with a significantly lower risk of CVD and all-cause mortality included not smoking, being physically active, having normal blood pressure, and having a glycated hemoglobin (HbA1c) level of <5.7%.

Similar results were found for IHD mortality risk, as not smoking, eating a healthy diet, and having a HbA1c level of <5.7% were independently associated with a significantly lower risk of IHD mortality.

Elevated blood pressure was the cardiovascular health metric associated with the largest adjusted population-attributable fractions (PAFs) for all-cause and CVD mortality. Smoking represented the second-largest PAF for all-cause mortality, and significantly contributed to CVD mortality.

Overall, meeting a greater number of cardiovascular health metrics was associated with a significantly lower risk of all-cause, CVD, and IHD mortality. Meeting a greater number of cardiovascular health metrics was also associated with a lower risk of mortality due to any cancer.

Comparing participants meeting ≥6 metrics with those meeting ≤1 metrics, there was a 51% decline in all-cause mortality risk, a 76% decline in CVD mortality risk, and a 70% decline in IHD mortality risk.

The authors discussed several study limitations. These included the fact that the NHANES III Linked Mortality File only included baseline measurements of cardiovascular health metrics. In addition, the NHANES data sets were sometimes inconsistent in their definitions of physical activity and healthy eating. Finally, modifiable risk factors such as obesity, smoking, and healthy diet may have confounding effects on other metrics and mortality risks, which resulted in an underestimation of their impact, according to the authors.