Some drugs increase blood cholesterol levels.
Diseases such as thyroid , kidney and liver disorders, diabetes , as well as several other less common disorders may increase blood cholesterol. Therefore, if you have a high level of HDL-C, you are not at risk, and usually have little, if any personal or family history of heart or vascular disease. However, in those with high triglyceride levels, this ratio may not be valid. As a general rule, however, a TC to HDL-C ratio greater than 5 indicates an increased risk, while a ratio below four is associated with reduced risk. In fact, it may decrease somewhat with age.