The association between serum lipids and intraocular pressure in two large UK cohorts

PURPOSE: Serum lipids are modifiable, routinely collected blood tests associated with cardiovascular health. We examined the association of commonly collected serum lipid measures (total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein (LDL-C) and triglycerides (TG)) with intraocular pressure (IOP). DESIGN: Cross-sectional study in the UK Biobank and EPIC-Norfolk cohorts. PARTICIPANTS: We included 94 323 participants of UK Biobank (mean age 57 years) and 6 230 participants of EPIC-Norfolk (mean age 68 years) with data on TC, HDL-C, LDL-C, TG collected between 2006-2009. METHODS: Multivariable linear regression adjusting for demographic, lifestyle, anthropometric, medical and ophthalmic covariables was used to examine the associations of serum lipids with IOPcc. MAIN OUTCOME MEASURES: IOPcc. RESULTS: Higher levels of TC, HDL-C and LDL-C were independently associated with higher IOPcc in both cohorts after adjustment for key demographic, medical and lifestyle factors. For each standard deviation increase in TC, HDL-C, and LDL-C, IOPcc (mmHg) was higher by 0.09 (95% CI: 0.06-0.11; P<0.001), 0.11 (95% CI 0.08-0.13; P<0.001), 0.07 (95% CI: 0.05-0.09, P<0.001), respectively in the UK Biobank cohort. In the EPIC-Norfolk cohort, each additional standard deviation in TC, HDL-C, and LDL-C was associated with a higher IOPcc (mmHg) by 0.19 (95% CI 0.07-0.31, P=0.001), 0.14 (95% CI 0.03-0.25, P=0.016), and 0.17 (95% CI 0.06-0.29, P=0.003). An inverse association between TGs and IOP in the UK Biobank (-0.05, 95% CI -0.08 to -0.03, P<0.001) was not replicated in the EPIC cohort (P=0.30). CONCLUSION: Our findings suggest that serum TC, HDL-C and LDL-C are positively associated with IOP in two UK cohorts and TGs may be negatively associated. Future research is required to assess whether these associations are causal in nature

The Association of Physical Activity with Glaucoma and Related Traits in the UK Biobank

PURPOSE: To examine the association of physical activity (PA) with glaucoma and related traits, to assess whether genetic predisposition to glaucoma modified these associations, and to probe causal relationships using Mendelian randomization (MR). DESIGN: Cross-sectional observational and gene-environment interaction analyses in the UK Biobank. Two-sample MR experiments using summary statistics from large genetic consortia. PARTICIPANTS: UK Biobank participants with data on self-reported or accelerometer-derived PA and intraocular pressure (IOP; n = 94 206 and n = 27 777, respectively), macular inner retinal OCT measurements (n = 36 274 and n = 9991, respectively), and glaucoma status (n = 86 803 and n = 23 556, respectively). METHODS: We evaluated multivariable-adjusted associations of self-reported (International Physical Activity Questionnaire) and accelerometer-derived PA with IOP and macular inner retinal OCT parameters using linear regression and with glaucoma status using logistic regression. For all outcomes, we examined gene-PA interactions using a polygenic risk score (PRS) that combined the effects of 2673 genetic variants associated with glaucoma. MAIN OUTCOME MEASURES: Intraocular pressure, macular retinal nerve fiber layer (mRNFL) thickness, macular ganglion cell-inner plexiform layer (mGCIPL) thickness, and glaucoma status. RESULTS: In multivariable-adjusted regression models, we found no association of PA level or time spent in PA with glaucoma status. Higher overall levels and greater time spent in higher levels of both self-reported and accelerometer-derived PA were associated positively with thicker mGCIPL (P < 0.001 for trend for each). Compared with the lowest quartile of PA, participants in the highest quartiles of accelerometer-derived moderate- and vigorous-intensity PA showed a thicker mGCIPL by +0.57 μm (P < 0.001) and +0.42 μm (P = 0.005). No association was found with mRNFL thickness. High overall level of self-reported PA was associated with a modestly higher IOP of +0.08 mmHg (P = 0.01), but this was not replicated in the accelerometry data. No associations were modified by a glaucoma PRS, and MR analyses did not support a causal relationship between PA and any glaucoma-related outcome. CONCLUSIONS: Higher overall PA level and greater time spent in moderate and vigorous PA were not associated with glaucoma status but were associated with thicker mGCIPL. Associations with IOP were modest and inconsistent. Despite the well-documented acute reduction in IOP after PA, we found no evidence that high levels of habitual PA are associated with glaucoma status or IOP in the general population. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references