By Martina M. McGrath, MD
August 22, 2017
Metabolic changes leading to the development of atherosclerosis can start early in life, and are frequently unrecognized in their early stages. For example, obesity in childhood and young adulthood has repeatedly been shown to increase the risk of cardiovascular disease (CVD) later in life.1,2 Given the current epidemic of obesity, inactivity, and poor diet, this is an issue of great public health importance. Tools aimed at young people that encourage early recognition of modifiable risk factors could have major clinical impact in the long term. However, estimating a young person’s risk of CVD, in the absence of typical CV risk factors such as diabetes or hypertension has proven challenging. The Framingham risk score and similar cardiac risk estimating equations are useful tools in middle-aged and older adults but are poorly validated in younger people due to their low absolute risk and the frequent lack of traditional CV risk factors.
The Healthy Heart Score (HHS) is a lifestyle-based score,3 developed to estimate the risk of CVD in adults aged 40-75 years. It comprises a very detailed online questionnaire of lifestyle, diet and exercise habits, along with age, BMI and smoking status. Initial studies showed good discrimination in predicting CV events at >20-year follow-up, particularly in patients whose baseline risk was low.
The CARDIA study, recently published in JAMA Internal Medicine, aimed to test the predictive value of the HHS risk score in assessing the 25-year risk of CV events (MI, coronary artery disease and stroke) in a group of young adults.4 This prospective cohort study followed 4,893 US-based young adults who enrolled at a mean age of 25 years, and were followed for 27 years for cardiovascular events. Only 9% of enrollees had a definable risk factor at enrollment (hypertension, diabetes, dyslipidemia).
During the follow-up period, 69 CV events occurred in 64 women and 104 CV events occurred in 99 men. The incidence of CV events was 0.9 per 1000 patient years for women and 1.75 per 1000 patient year for men, occurring at a mean age of 45.9 years. Seventy-five percent of these individuals did not have defined CV risk factors at baseline. However, patients that had an event tended to have higher BMI and poorer lifestyle habits at baseline.
On analysis, HHS performed moderately well at predicting CV events in young people, with a C statistic of 0.71 (95% CI 0.66-0.76). It showed greater predictive value in men than women, and in those without traditional CV risk factors at baseline. Its predictive value was lower for those with hypertension or diabetes at baseline. Limitations in this analysis include self-reporting of all data, with the risks of recall bias. Data regarding family history, illicit drug use and pregnancy outcomes were not included and could have improved the discriminatory value of the score.
Despite its moderate predictive value, the HHS is likely to be useful in clinical practice. As a self-administered questionnaire, it allows patients to see which areas of their lifestyle or diet are contributing to increased CV risk, allows them to track the effect of changes, and could support efforts to promote healthy lifestyle choices.
- Asheley C. Skinner, Ph.D., Eliana M. Perrin, M.D., M.P.H., Leslie A. Moss, M.H.A., C.H.E.S., and Joseph A. Skelton, M.D. Cardiometabolic Risks and Severity of Obesity in Children and Young Adults. N Engl J Med 2015; 373:1307-1317
- Paul W. Franks, Ph.D., Robert L. Hanson, M.D., M.P.H., William C. Knowler, M.D., Dr.P.H., Maurice L. Sievers, M.D., Peter H. Bennett, M.B., F.R.C.P., and Helen C. Looker, M.B., B.S. Childhood Obesity, Other Cardiovascular Risk Factors, and Premature Death. N Engl J Med 2010; 362:485-493
- Gooding HC, Ning H, Gillman MW, Shay C, Allen N, Goff DC, Lloyd-Jones D, Chiuve S. Application of a Lifestyle-Based Tool to Estimate Premature Cardiovascular Disease Events in Young Adults. The Coronary Artery Risk Development in Young Adults (CARDIA) Study. JAMA Intern Med. Published online July 17, 2017. doi:10.1001/jamainternmed.2017.2922
Dr. Martina McGrath is an Instructor in Medicine at Harvard Medical School, and a member of the Renal Division, Department of Medicine, at Brigham and Women’s Hospital, both in Boston. Dr. McGrath is the Medical Editor for the Trends in Medicine blog.