Understanding the Coronary Artery Calcium (CAC) Score
A Coronary Artery Calcium (CAC) score is a diagnostic tool used to measure the amount of calcified plaque in your coronary arteries. This plaque is a sign of atherosclerosis, a disease where plaque builds up inside the arteries. The score, derived from a non-invasive CT scan, is a powerful predictor of future cardiovascular events, such as heart attacks and strokes. The higher the score, the more plaque is present and the greater the risk. While the score is often considered in isolation, its true value lies in assessing an individual's risk in comparison to others of the same age and sex.
The Relationship Between Age and Calcium Score
It is a natural part of the aging process for some degree of plaque buildup to occur in the arteries. Consequently, calcium scores generally increase with age. For a 70-year-old, some level of coronary artery calcium is expected and does not necessarily indicate an impending health crisis. The key is to contextualize the score by looking at population data and comparing it to what's considered typical for that age bracket. This shift in perspective is critical, especially when considering medical interventions, as a score that might be alarming for a 50-year-old is often considered expected for someone 20 years older.
What Population Data Reveals About the Average 70-Year-Old
While providing a single "average" number can be misleading due to significant variability, studies provide valuable insights into typical ranges. According to research, the median coronary artery calcium score for individuals in the 65-75 age group was around 110 Agatston units. Other studies focusing on older adults, with a mean age of 80, showed an even higher median score of 330. It is important to note the difference between a mean (arithmetic average) and a median (middle value), as a median often provides a better representation when dealing with a wide range of scores. In older populations, the median is more informative as high scores in a few individuals can skew the mean. For many people in their 70s, a score over 100 is not uncommon.
Understanding Percentiles and Risk
Rather than fixating on a single average, medical professionals often use percentiles to interpret a CAC score. This approach compares your score to those of others in your specific age, sex, and race group. Being in the 75th percentile, for example, means your score is higher than 75% of your peers. This method is particularly useful for older adults, as a score that is simply average for a 70-year-old could still place a younger person in a much higher risk category. Percentile rankings help guide the intensity of medical intervention and lifestyle changes, tailoring the response to the individual's specific risk profile. For example, a 70-year-old with a score of 150 might be considered below average and at lower risk than a 40-year-old with the same score.
Risk Stratification Based on CAC Scores
Here is a general guide to interpreting CAC scores, though a doctor’s consultation is essential:
- Score of 0: Low risk. Indicates no plaque is visible. For a 70-year-old, this is a very favorable result, though it is less common. Studies show about 5% of men aged 70 or older have a zero score.
- Score 1–100: Mild plaque present. This is a common finding in aging adults and suggests a low-to-mild risk. Lifestyle modifications may be recommended.
- Score 101–400: Moderate plaque present. This signifies an increased risk of a cardiac event. Doctors will likely recommend medication, such as statins, and more aggressive lifestyle changes.
- Score >400: Significant plaque present. This indicates extensive atherosclerosis and a high risk of future cardiovascular events. Aggressive risk-reducing therapies are typically necessary.
A Comparison of CAC Scores Across Age Groups
| Age Group (Years) | Typical Median CAC Score | Interpretation | Common Medical Action |
|---|---|---|---|
| 40-54 | ~0 | Minimal to no plaque, low risk. | Observation, lifestyle awareness. |
| 55-64 | 75–150 (varies) | Mild to moderate plaque likely, risk increasing. | Lifestyle modifications, potential for statin therapy. |
| 65-75 | ~110 | Moderate plaque expected, risk elevated. | Statin therapy often recommended, lifestyle focus. |
| 75+ | High (e.g., median 330 at age 80) | Significant plaque common, risk management is key. | Aggressive risk reduction, focusing on overall health. |
Lifestyle Adjustments and Medical Guidance
Regardless of your calcium score, lifestyle interventions are crucial for maintaining heart health, especially as you age. These practices can help slow the progression of plaque buildup and mitigate cardiovascular risk. Consistent consultation with a healthcare provider is the best way to interpret your score and develop an effective management plan. The American College of Cardiology provides up-to-date guidance on risk assessment and management for older adults, which can be an excellent resource. Find out more from the ACC here.
Conclusion
For a 70-year-old, there is no single "average" calcium score that perfectly captures cardiovascular risk. The more informative figure is often the median, which suggests that a moderate score around 110 Agatston units is common for the 65-75 age group. Scores must be evaluated within the context of an individual's specific health profile, including sex, lifestyle, and other risk factors. A physician's interpretation, often referencing percentile data, is essential for translating a CAC score into a meaningful cardiovascular risk assessment and guiding appropriate preventative or management strategies. Understanding this dynamic helps individuals in their 70s and beyond take proactive steps to protect their heart health.
