Moreover, given the predictable fluc- tuations of health dynamics, such shared decisions should be reconsidered regularly. 3. Multiple studies indicate the utility of CAC mea- surement in identifying the absence of atheroscle- rotic pathophysiology in older adultsS4.4.4.1-10,S4.4.4.1-11 Moreover, with reduced costs, the long-term con- sequences of using low-dose computed tomogra- phy for CAC screening are much less concerning for older patients. If CAC score is zero, the patient may be reclassified to a lower-risk status to avoid The BioImage study also indicated that scanning for carotid plaque did not down-classify as many individuals as did a CAC score of zero but still improved specificity of Limiting statin therapy to those with CAC scores greater than zero, com- bined with clinical judgment and patient prefer- ence, could provide a valuable awareness with which to inform shared decision-making. 4.4.4.2. Young Adults (20 to 39 Years of Age) Much of atherosclerosis begins in young adulthood.S4.4.4.2-1 Progression of atherosclerosis thereafter becomes clini- cally manifest as ASCVD in middle age or later years. Thus, prevention of clinical ASCVD optimally begins early in life. In children or adolescents, atherosclerosis may begin to appear in those with hypercholesterol- emia; in this age range, more aggressive cholesterol- lowering may be indicated. Development of atheroscle- rosis in young adults most commonly is multifactorial and occurs most rapidly in individuals with multiple risk factors (eg, hypercholesterolemia, hypertension, ciga- rette smoking, diabetes mellitus, and obesity).S4.4.4.2-2 As discussed in these guidelines (Section 4.2.) FH of- ten goes undiagnosed. Young adults with primary el- evations of LDL-C 190 mg/dl have a long-term ASCVD and statin therapy is recommended. In adults with hypercholesterolemia, cascade screening often identifies other family members with elevated LDL-C (Section 4.2.). 