A 27-year-old otherwise healthy non-smoking man presents to his GP with a 3-week history of exertional central chest tightness relieved by rest. ECG at rest is normal and his cardiovascular examination is unremarkable. His 5-year absolute cardiovascular risk is <5% and fasting lipids show total cholesterol 5.2 mmol/L, LDL-C 3.1 mmol/L, HDL-C 1.4 mmol/L and triglycerides 1.2 mmol/L. What is the most appropriate initial management strategy?