Assessment of Coronary Artery Calcium in Active Duty Enlisted Military Members With 10 or More Years of Service

Hypothesis: Enlisted military members with 10 or more years of service and at least one cardiovascular risk factor will demonstrate a higher risk of future cardiac events as assessed by coronary artery calcium (CAC) scoring than the risk calculated by the Framingham Risk Score.

Study Overview

• Status: Terminated
• Conditions: Atherosclerosis; Plaque, Atherosclerotic

Detailed Description

While the military is making strides towards improving the health and habits of service members, there are many aspects of the military culture that negatively affect the cardiovascular health of military members. Smoking/tobacco use, poor eating habits with Meals Ready-to-eat (MRE) and ready access to fast food establishments on base, inconsistent exercise, the socioeconomic status of enlisted members and the stress of deployment are all factors that contribute to increased risk of cardiovascular disease during military service. Currently the calculation of a patient's Framingham risk score is the most commonly used method of calculating a patient's cardiovascular risk, and this calculation is based on age, smoking history, blood pressure, and lab values and compares it to a general population's risk. By the use of a cardiac computerized topography (CT) scan, a Coronary Artery Calcium (CAC) score can be calculated and used to estimate the degree of atherosclerosis already present in each patient's coronary arteries, and thus establishing their risk of future cardiovascular events. CAC scoring is a more patient-specific way of identifying cardiovascular risk. The purpose of this study is to assess the prevalence of atherosclerosis in enlisted military members with at least 10 years of service and one or more cardiovascular risk factor and to determine if their risk of a cardiovascular event is higher than predicted by the Framingham score. If CAC scoring is demonstrated to be more accurate, particularly if it is more likely to detect risk, it may be used in the future to better risk stratify this population of the military. The CAC results in patients could also be a motivating factor to create changes in the military culture to attempt to mitigate these risks and create a healthier fighting force.

• Study Type: Observational
• Enrollment (Actual): 112

Contacts and Locations

Study Locations

• United States
  • California
    • Travis Air Force Base, California, United States, 94535
      • David Grant USAF Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 35 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Active duty military enlisted members with 10 or more years of service

Description

INCLUSION Criteria:

Active Duty Military Members with at least 10 years of service

Enlisted Rank

Males 35 years and older OR Females 45 years and older (please note the age difference is due to the fact that female plaque formation with calcification has been shown to lag that of males by about 10 years)

One or More of the Following Risk Factors:

Smoker - at least 5 pack years in the past 5 years (pack year = number of packs per day number of years of smoking)

Diabetic (Fasting glucose of >125 mg/dL on two or more blood draws, or Random Blood Glucose of >200 mg/dL on a single blood draw, or Hemoglobin A1C >6.5%, or previous diagnosis of diabetes listed in the subject's medical record) or Pre-diabetic (Fasting glucose >100 on two or more blood draws or Hgb A1C 5.7-6.4)

Hypertension (Systolic BP > 140 or Diastolic BP >90 or on blood pressure medications or diagnosis of hypertension in medical record)

Waist Circumference > 40 inches for males or >35 inches for females

Hyperlipidemia (LDL>130, HDL<40 for males, HDL <50 for females, Triglycerides >200, on lipid lowering medications and/or diagnosis of hyperlipidemia in medical record)

EXCLUSION Criteria:

Males <35 years old

Women <45 years old (please note the age difference is due to the fact that female plaque formation with calcification has been shown to lag that of males by about 10 years)

Officer Rank - officers are excluded as we are looking at the enlisted culture in the military.

History of any of the following:

Coronary Artery Disease (CAD)

Coronary Artery Bypass Grafting (CABG)

Myocardial Infarction (MI)

Percutaneous Intervention/Stent Placement (PCI)

Angina

Radiotherapy (external beam, brachytherapy, radiopharmaceutical)

Under the care of any of the following types of providers in the past 12 months (As these subjects are at greater risk of having had significant radiation exposure to the chest over the past 12 months):

Radiation/Medical Oncologist

Interventional Radiologist

Cardiologist

Cardiothoracic Surgeon

Vascular Surgeon

Females who think they may be pregnant

Pregnant females

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prevalence of Atherosclerosis	Percent of active duty enlisted military members with 10 or more years of military service determined to have a prevalence of atherosclerosis based on CAC risk category. The CAC risk category (scale), is derived from the CAC score (i.e., an estimate of the degree of atherosclerosis present in each participant's coronary arteries, reported as a number), and percentage by age to establish risk of future CV events. There are 5 risk categories: Low risk = CAC of 0 and no cardiovascular (CV) risk factors, Low - Moderate risk = CAC of 0 with CV risk factors, Moderate - High risk: CAC 1-100 and percentile for age <75%, High risk = CAC 100-399 or percentile for age >75%, Very high risk = CAC >100 and percentile for age >90% or CAC >400". Low risk is the best outcome, and very high risk is the worst.	within 10 days of CT scan
Rate of Reclassification	Percent/Number of subject that were reclassified from FRS to CAC risk category using CAC scores. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, very high. The Framingham risk category (scale) = FRS to estimate the risk of a CV event over the next 10 years. The FRS uses age, systolic blood pressure, high-density lipoprotein (HDL) cholesterol level, total cholesterol level, and smoking status to create a score that is converted into a 10-year CV disease risk % that correlates into a risk category: low, moderate, moderate - high risk, very high. For both scales, low is the best and very high is the worst outcome	within 10 days of CT scan
Compare FRS to the CAC - At Least One Additional Risk Factor	Compare FRS risk category to CAC risk category for enlisted subjects with at least 10 years of service and at least one additional CV risk factor to determine how well the results correlate with one another using the Spearman's Rank Correlation Coefficient. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, very high. The Framingham risk category (scale) = FRS to estimate the risk of a CV event over the next 10 years. The FRS uses age, systolic blood pressure, high-density lipoprotein (HDL) cholesterol level, total cholesterol level, and smoking status to create a score that is converted into a 10-year CV disease risk % that correlates into a risk category: low, moderate, moderate - high risk, very high. For both scales, low is the best and very high is the worst outcome	within 10 days of CT scan

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Metabolic Syndrome - Compare FRS to CAC	Compare FRS category and CAC risk category for those meeting and not meeting criteria for metabolic syndrome. Calculate Fisher's Exact test statistic and associated p values to look at the relationship between the presence/absence of metabolic syndrome and the FRS and CAC risk category. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, very high. The Framingham risk category (scale) = FRS to estimate the risk of a CV event over the next 10 years. The FRS uses age, systolic blood pressure, high-density lipoprotein (HDL) cholesterol level, total cholesterol level, and smoking status to create a score that is converted into a 10-year CV disease risk % that correlates into a risk category: low, moderate, moderate - high risk, very high. For both scales, low is the best and very high is the worst outcome	within 10 days of CT scan
Living in the Dorms - Compare FRS to CAC	Compare FRS category to CAC risk category for those who lived in the dorms > 5 years and < 5 years. Calculate Fisher's Exact test statistic and associated p values to look at the relationship between those who lived in the dorms > 5 years and < 5 years and the FRS and CAC risk category. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, very high. The Framingham risk category (scale) = FRS to estimate the risk of a CV event over the next 10 years. The FRS uses age, systolic blood pressure, high-density lipoprotein (HDL) cholesterol level, total cholesterol level, and smoking status to create a score that is converted into a 10-year CV disease risk % that correlates into a risk category: low, moderate, moderate - high risk, very high. For both scales, low is the best and very high is the worst outcome	within 10 days of CT scan
Physical Fitness (PT) Failures - Compare FRS to CAC	Compare FRS category to CAC risk category for those with and without PT failures. Calculate Fischer's Exact test statistic and associated p values to look at the relationship between those with and without PT failures and the FRS and CAC risk category. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, very high. The Framingham risk category (scale) = FRS to estimate the risk of a CV event over the next 10 years. The FRS uses age, systolic blood pressure, high-density lipoprotein (HDL) cholesterol level, total cholesterol level, and smoking status to create a score that is converted into a 10-year CV disease risk % that correlates into a risk category: low, moderate, moderate - high risk, very high. For both scales, low is the best and very high is the worst outcome	within 10 days of CT scan
Years of Military Service - Compare FRS to CAC	Compare FRS category to CAC risk category for those with 10-14, 15-19, 20-24 and 25+ years of military service. Calculate Fisher's Exact test statistic and associated p values to look at the relationship between those with 10-14, 15-19, 20-24 and 25+ years of military service and FRS & CAC risk category. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, very high. The Framingham risk category (scale) = FRS to estimate the risk of a CV event over the next 10 years. The FRS uses age, systolic blood pressure, high-density lipoprotein and total cholesterol levels, and smoking status to create a score that is converted into a 10-year CV disease risk % that correlates into a risk category: low, moderate, moderate - high risk, very high. For both scales, low is the best and very high is the worst outcome	within 10 days of CT scan
Additional Cardiovascular Risk Factors - Compare FRS to CAC	Compare FRS category to CAC risk category for those with 1 risk factor (RF), vs 2 RF, vs 3 RF, vs 4 RF, vs 5 CV risk factors. Calculate Fisher's Exact test statistic and associated p values to look at the relationship between those with 1 RF, vs 2 RF, vs 3 RF, vs 4 RF, vs 5 CV RF and the FRS & CAC risk category. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, very high. The Framingham risk category (scale) = FRS to estimate the risk of a CV event over the next 10 years. The FRS uses age, systolic blood pressure, high-density lipoprotein and total cholesterol levels, and smoking status to create a score that is converted into a 10-year CV disease risk % that correlates into a risk category: low, moderate, moderate - high risk, very high. For both scales, low is the best and very high is the worst outcome	within 10 days of CT scan
Metabolic Syndrome - CAC	Compare CAC risk category between two groups, those that meet criteria for metabolic syndrome and those that do not, to see if there is an association between the groups and CAC risk category. The number of participants in each risk category will be added. Then the total number for each group will be used to calculate the correlation using Fisher's Exact test and reported as a p value. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, high, very high. Low risk is the best outcome, and very high risk is the worst	within 10 days of CT scan
Living in the Doors - CAC	Compare CAC risk category between two groups, those who lived in the dorm for > 5 years and < 5 years, to see if there is an association between the groups and CAC risk category. The number of participants in each risk category will be added. Then the total number for each group will be used to calculate the correlation using Fisher's Exact test and reported as a p value. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, high, very high. Low risk is the best outcome, and very high risk is the worst outcome	within 10 days of CT scan
PT Failures - CAC	Compare CAC risk category between two groups, those with and without a PT failures, to see if there is an association between the groups and CAC risk category. The number of participants in each risk category will be added. Then the total number for each group will be used to calculate the correlation using Fisher's Exact test and reported as a p value. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, very high. Low risk is the best outcome, and very high risk is the worst outcome	within 10 days of CT scan
Years of Military Service - CAC	Compare CAC risk category among groups, those with 10-14, 15-19, 20-24, and 25+ years of military service, to see if there is an association between overall years of military service and CAC risk category. The number of participants in each risk category will be added. Then the total number for each group will be used to calculate the correlation using Fisher's Exact test and reported as a p value. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, very high. Low risk is the best outcome, and very high risk is the worst outcome	within 10 days of CT scan
Additional Risk Factors - CAC	Compare CAC risk category among groups, those with 1 risk factor (RF) vs. 2 RF, vs 3 RF, vs 4 RF, vs 5 RF (as listed in the inclusion criteria), to see if there is an association between the groups and CAC risk category. The number of participants in each risk category will be added. Then the total number for each group will be used to calculate the correlation using Fisher's Exact test and reported as a p value. The CAC risk category (scale) = CAC score (estimated degree of calcium in coronary arteries, a number) + percentage by age to establish risks of future CV events. There are 5 risk categories: low, low - moderate, moderate - high, very high. Low risk is the best outcome, and very high risk is the worst outcome	within 10 days of CT scan

Collaborators and Investigators

• Sponsor: David Grant U.S. Air Force Medical Center
• Investigators: Principal Investigator: Elijah Burton, MD, David Grant USAF Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): November 5, 2013
• Primary Completion (Actual): July 18, 2018
• Study Completion (Actual): July 18, 2018

Study Registration Dates

• First Submitted: December 9, 2013
• First Submitted That Met QC Criteria: December 9, 2013
• First Posted (Estimate): December 12, 2013

Study Record Updates

• Last Update Posted (Actual): June 9, 2020
• Last Update Submitted That Met QC Criteria: May 27, 2020
• Last Verified: May 1, 2020

More Information

Terms related to this study

• Keywords: Atherosclerosis; Cardiovascular; CT Scan; Military Active Duty Enlisted; Coronary Artery Calcium (CAC); CAC Score; Framingham Score
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Pathological Conditions, Anatomical; Atherosclerosis; Plaque, Atherosclerotic
• Other Study ID Numbers: FDG20130024H

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No