For young adults, the benefits of lipid testing and treatment are less clear because the immediate risks of heart attacks and strokes in this age group are typically very low. Current testing guidelines for young adults vary across the major health-related organizations and, in general, recommend less-frequent monitoring than older adults. (For more on this, see the screening article for High Cholesterol in Young Adults.) However, there is mounting evidence that abnormal lipid levels in young adulthood can lead to health problems later in life. Though harmful levels may not directly increase the risk of heart attacks and strokes in this age group, an increasing number of studies are pointing to delayed adverse effects.
The study, termed the Coronary Artery Risk Development in Young Adults (CARDIA), adds to the accumulating data that lipids play a role in the future heart health of young adults. The study involved over 3,000 people from 4 different cities in the United States. Researchers repeatedly measured participants’ lipid levels during young adulthood, from age 20 through 34, using tests for low-density lipoprotein cholesterol (LDL-C or "bad cholesterol"), high-density lipoprotein cholesterol (HDL-C or "good cholesterol"), and triglycerides. The results of the lipid tests were averaged over the time of the study.
When excess lipids and other substances in the blood are deposited in artery walls, they harden to form structures called plaques. This occurs because of the inclusion of calcium in these deposits. This condition is called atherosclerosis and the presence of these plaques restricts blood flow through arteries and can lead to the development of CVD. The presence of calcium in arteries, because it reflects the presence of plaques, is therefore a predictor of CVD.
At fifteen years and twenty years after the start of the study, the researchers used cardiac computed tomography (CT) to measure the amount of calcium that was present in the arteries of the heart in each participant. They noted the presence of calcium in the arteries of some participants, which therefore strongly predicts the development of CVD in those affected.
The researchers found relationships between lipid measurements in the young adults and the amount of coronary calcium detected when they reached an older age. For example, participants who maintained an optimal LDL-C level (averaged over the course of the study) were much less likely to have coronary calcium compared to those who had high averaged levels of LDL-C: 18% compared to 44%. An optimal level of LDL-C is less than 100 mg/dL (2.59 mmol/L) while a level greater than 160 mg/dL (4.15 mmol/L) is considered high. In addition, the amount of coronary calcium was found to be higher in participants with low levels of HDL than those with high HDL, the lipoprotein that protects against development of CVD.
Results of this study suggest that maintaining healthy lipid levels as a young adult could be beneficial as one ages. It remains to be seen, however, if major health-related organizations will decide that a change to current testing guidelines is necessary to identify young adults who are at a greater risk of future CVD, based on this study and others like it. In addition, questions remain as to which type of interventions might be successful in treating unhealthy levels in this population. Would testing young adults and treating them on an individual basis, perhaps with lipid-lowering medications, be effective? Would stronger public health messages that address other risk factors such as weight, diet and lack of exercise be more helpful? Further research in these areas is necessary before these questions can be answered.
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Conditions: Cardiovascular Disease
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
(August 3, 2010) Berenson G, Srinivasan S. Editorial - Cardiovascular Risk in Young Persons: Secondary or Primordial Prevention? Annals of Internal Medicine, Vol. 153 no. 3, Pp 202-203.
(March 15, 2010) Cardiac CT for Calcium Scoring. Radiology.org. Available online at http://www.radiologyinfo.org/en/info.cfm?pg=ct_calscoring through http://www.radiologyinfo.org. Accessed September 2010.