Intraocular Pressure Associated Positively with Higher Serum Lipid Measures

Kian M. Madjedi, MD, MPhil

Higher concentrations of serum lipid measures, including total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) had positive associations with intraocular pressure (IOP), according to new findings.

Meanwhile, data from the 2 large study cohorts based in the United Kingdom suggest triglyceride levels may be associated negatively with IOP.

“Our study found a consistent positive association between HDL-C and IOP, clarifying inconsistent associations reported previously,” wrote study author Kian M. Madjedi, MD, MPhil, Department of Ophthalmology, University of Calgary.

As modifiable risk factors for cardiovascular disease (CVD), serum lipid measures are collected routinely and widely available. However, the association between serum lipid fractions and cholesterol components have been varied in previous examinations.

The cross-sectional study included 94,323 participants from the UK Biobank with a mean age of 57 years and 6230 participants from the EPIC-Norfolk with a mean age of 68 years. Serum measures, including total cholesterol, HDL-C, LDL-C, and triglycerides, were collected between 2006 and 2009, according to investigators.

Investigators used multivariate linear regression analysis to examine the association of serum lipids and corneal-compensated IOP (IOPcc), after adjusting for demographics, lifestyle, anthropometric, medical, and ophthalmic covariables.

Data show the mean IOPcc was 16.1 ± 3.3 mmHg and 17.1 ± 3.9 mmHg in the UK Biobank and EPIC-Norfolk cohorts, respectively.

Through multivariate analysis, investigators observed higher levels of total cholesterol, HDL-C, and LDL-C were associated independently with higher IOPcc in both cohorts after adjustments. Meanwhile, higher triglyceride levels were associated with lower IOPcc only in the UK Biobank.

In the UK Biobank cohort, each 1-standard deviation increase in total cholesterol led to higher IOPcc by 0.09 mmHg (95% confidence interval [CI], 0.06 - 0.11 mmHg; P <.001).For each 1-standard deviation increase in HDL-C and LDL-C,  the IOPcc was 0.11 mmHg (95% CI, 0.08 - 0.13 mmHg; P <.001) and 0.07 mmHg (95% CI, 0.05 - 0.09 mmHg; P <.001) higher, respectively.

Moreover, in the EPIC-Norfolk cohort, each 1-standard deviation increase in total cholesterol, HDL-C, and LDL-C was associated with a higher IOPcc by 0.19 mmHg (95% CI, 0.07 - 0.31 mmHg; P = .001), 0.14 mmHg (95% CI, 0.03 - 0.25 mmHg; P = .016), and 0.17 mmHg (95% CI, 0.06 - 0.29 mmHg; P = .003).

In the UK Biobank, IOP was 0.05 mmHg lower (95% CI, 0.08 - 0.03 mmHg; P <.001) for each additional 1-standard deviation in triglyceride levels. However, there was no significant association identified with triglyceride levels in the EPIC-Norfolk cohort (β = -0.05 mmHg; 95% CI, -0.15 to 0.05 mmHg; P = .30).

Madjedi determined that future research is required to assess whether the association may be causal in nature.

“The identification of an underlying causal association between lipids or cholesterol components and IOP would be clinically significant because lipid levels can be modified through diet, lifestyle, and medication,” Madjedi concluded.

The study, “The Association between Serum Lipids and Intraocular Pressure in Large United Kingdom Cohorts,” was published in Ophthalmology.