Researchers here suggest that the processes of atherosclerosis, leading to the buildup of fatty deposits that narrow and weaken blood vessels, are cumulative over time. One of the risk factors is high blood cholesterol, and high cholesterol in youth is found to correlate with increased risk in later life, even if blood cholesterol has been restored to normal levels at that time. This is interesting, as the cause of atherosclerosis is less blood cholesterol per se and more the oxidized cholesterol that disrupts the function of macrophage cells responsible for cleaning up cholesterol in blood vessel walls. Those macrophages should be working just fine in genetically normal young people with high cholesterol, as oxidized cholesterol is a feature of aging, and should be only minimally present in the young. This suggests that perhaps the researchers are seeing the ongoing, lifetime effects of the sort of neglect of health that is required to obtain high blood cholesterol when young, rather than a specific disease process.
An ongoing study, funded by the National Heart, Lung, and Blood Institute, began 35 years ago, recruiting 5,000 young adults aged 18 to 30. Researchers have tracked this cohort ever since to understand how individual characteristics, lifestyle, and environmental factors contribute to the development of cardiovascular disease later in life. "We found having an elevated LDL cholesterol level at a young age raises the risk of developing heart disease, and the elevated risk persists even in those who were able to later lower their LDL cholesterol levels. Damage to the arteries done early in life may be irreversible and appears to be cumulative. For this reason, doctors may want to consider prescribing lifestyle changes and also medications to lower high LDL cholesterol levels in young adults in order to prevent problems further down the road."
To conduct the study, the researchers used complex mathematical modeling to understand how cardiovascular risk (heart attack, stroke, blood vessel blockages, and death from cardiovascular disease) rises with increasing cumulative "exposure" to LDL cholesterol over an average of 22 years. They found that the greater the area under the "LDL curve" - which measured time of exposure and level of LDL cholesterol over time - the more likely participants were to experience a major cardiovascular event. While the medical establishment understands the importance of managing high LDL cholesterol levels to lower heart risks, there is little consensus on how aggressively to intervene in young adults who may not experience a heart attack or stroke for decades.