Good cholesterol, wasn't it good? ... Does it increase the risk of 'this disease' in the eyes?

A 55-year-old adult with good HDL cholesterol levels is said to have a high risk of glaucoma.

Research has shown that HDL cholesterol, known as good cholesterol, may be associated with an increased risk of glaucoma. [Photo=Getty Images Bank]

Research has shown that HDL (high-density lipoprotein) cholesterol, known as good cholesterol, may be associated with an increased risk of glaucoma. Conversely, LDL (low-density lipoprotein) cholesterol, known as bad cholesterol, was found to be related to a decreased risk of glaucoma. However, these results were only observed in adults aged 55 and older.

Cholesterol is a component of cell membranes surrounding cells, used to produce bile, a digestive fluid, and serves as a raw material for various steroid hormones and vitamin D, which strengthens bones. Cholesterol is classified into neutral fats, HDL cholesterol, and LDL cholesterol depending on the degree of binding with proteins in the blood.

Among them, LDL cholesterol accumulates on the arterial walls when present in excess of the body's needs, leading to arteriosclerosis. On the other hand, HDL cholesterol transports cholesterol from cells to the liver, where it is metabolized, acting as a cleaner and helping to prevent heart disease and stroke. Due to these properties, HDL cholesterol is commonly called "good" cholesterol, while LDL cholesterol is called "bad" cholesterol.

The research team at Zhongshan University Zhongshan Eye Center in China conducted a study involving 402,029 adults aged 40 to 69 who are participating in the UK Biobank research in the United Kingdom. They investigated the relationship between serum lipid levels and glaucoma. Glaucoma is a disease characterized by increased intraocular pressure that damages the optic nerve.

During an average follow-up period of 14 years, glaucoma developed in 6,868 people (1.72%), and the analysis showed that higher HDL cholesterol levels tended to increase the risk of glaucoma.

Upon closer inspection, participants with the highest HDL cholesterol levels had a 10% higher likelihood of developing glaucoma compared to those with the lowest levels, and the risk of glaucoma increased by 5% for each standard deviation increase.

Meanwhile, participants with the highest LDL cholesterol and triglyceride levels had an 8% and 14% lower risk of developing glaucoma, respectively, compared to those with the lowest levels, and the risk decreased by 4% for each standard deviation increase.

However, this correlation was only observed in individuals aged 55 and older, and no significant association was found in other age groups.

The researchers stated that it is still unclear why various types of cholesterol influence the risk of glaucoma. Additionally, the study is observational, so it cannot establish causality. The fact that blood samples were only collected at a single point in time and that most participants were Europeans were also pointed out as limitations of the study.

However, the research team stated, "These findings challenge the existing paradigm of 'good' and 'bad' cholesterol related to eye health," and added, "If these results are validated through follow-up studies, it may be necessary to reevaluate the use of cholesterol-lowering medications in patients at risk of glaucoma."

Furthermore, it has been considered the "good cholesterol" for 70 years, but this study shows that high HDL cholesterol levels are not always associated with a good prognosis, and concluded that further research is needed to investigate the mechanisms behind this association.

This research result was published in the British Journal of Ophthalmology under the title 'Associations between serum lipids and glaucoma: a cohort study of 400,229 UK Biobank participants.'

jihami pcraemi@kormedi.com