High cholesterol: introduction
Cholesterol is a fatty substance produced primarily in the liver that has an essential role in communication between cells and the production of hormones and vitamin D (Craig et al, 2018). However, lifestyle and genetic factors can cause chronic elevation of blood cholesterol levels, which in turn is associated with increased risk of heart disease, peripheral artery disease and stroke (British Heart Foundation [BHF], 2025). More information on the causes of high cholesterol can be found in the section on Risk Factors.
Cholesterol is packaged into lipoproteins for distribution through the bloodstream. Depending on their composition, lipoproteins can have either positive or negative impacts on health. High-density lipoprotein (HDL), also known as “good” cholesterol, helps remove excess cholesterol from the blood and has an anti-inflammatory effect (Heart UK, 2025). Conversely, low-density lipoprotein (LDL), also known as “bad” cholesterol, when in excess contributes to blocking or narrowing of the arteries that increases risk of heart and arterial disease (Heart UK, 2025) (see ScotPHO sections on Heart Disease and Stroke for more information). Whilst the distinction between HDL and LDL is important, LDL makes up 60-70% of total blood cholesterol, and it is total cholesterol which is considered in these pages.
Non-familial high cholesterol does not typically present with symptoms and is therefore screened for and diagnosed through a blood test. Testing is suggested by the NHS for those aged over 40, those who are overweight, and those for whom high cholesterol or heart problems run in the family (National Health Service [NHS], 2022). In contrast, familial high cholesterol may present with symptoms including:
- corneal arcus (a pale ring around the iris of the eye)
- tendon xanthomata (swelling of the knuckles, knees or Achilles tendon)
- xanthelasmas (small yellow lumps of cholesterol that build up around the eye) (BHF, 2025)
Management of high cholesterol is primarily concerned with reducing the ratio of LDL to HDL through lifestyle changes, for example by eating a balanced diet, becoming more active and quitting smoking (NHS, 2022). High cholesterol can also be managed pharmaceutically with drugs such as statins, which reduce LDL by up to 50% (Heart UK, 2025). However, patient care is increasingly focused on assessing global cardiovascular risk rather than considering blood cholesterol levels in isolation.
In 2021, the Global Burden of Disease study reported that heart disease and stroke were the first and fourth greatest contributors respectively to morbidity and mortality in Scotland. Therefore, as the World Health Organisation attributes one third of ischaemic heart disease globally to high cholesterol, high cholesterol represents a significant but actionable public health concern (World Health Organisation [WHO], 2025).
