1 Age-related factors Serum total cholesterol levels tend to increase with age, but generally decrease after 70 and 80 years old. Before and after menopause, women have more chances to suffer from hyperlipidemia than other periods.

2 Pregnancy factors During pregnancy, due to the physiological needs of mothers and babies, the level of total cholesterol in pregnant women's serum will be higher than that before pregnancy.

3 Dietary factors Long-term intake of high saturated fatty acids and high calorie diet can lead to an increase in serum total cholesterol levels. People who like to eat animal fat or cholesterol-rich foods on weekdays are also prone to increase serum total cholesterol levels.

4 genetic factors the level of cholesterol in blood can be regulated by genetic genes. For example, people with family hereditary diseases such as hypercholesterolemia and familial mixed hyperlipidemia have elevated serum total cholesterol.