Evaluation Of Risk Factors And Retinal Blood Vessel Calibre In Lifestyle-Protected Individuals In The Irish Nuns Eye Study Compared To The European Eye Study

Abstract

 

Purpose:

 

The Irish Nun Eye Study (INES) was designed primarily to assess the prevalence of Age-related Macular Degeneration (AMD) in a community with a protected lifestyle. Nuns from the island of Ireland were enrolled (n=1242). Information collected included demographic, medical, ophthalmic, medical, dietary and UVR exposure data. The aim of this part of the study was to compare the prevalence of cardiovascular risk factors and vascular calibre in the 2 groups.

 

Methods:

 

All participants had a full ophthalmic examination, including fundus photographs. All data were entered into SPSS and the prevalence of the cardiovascular risk factors were assessed for both complete groups. One hundred eyes from 100 participants from each study were then selected for measurement of vascular calibre using custom-written vessel segmentation and analysis software (QUB). For the purpose of this analysis we chose the major superior and inferior artery and vein pair for every image. All values were corrected for refractive error using the Spherical Equivalent Refraction (SER) for each eye.

 

Results:

 

Data for 1242 and 313 female participants from the INES and EurEye Study were available. The mean age of participants for INES was 77.7 years, while those for EurEye were slightly younger, with a mean age of 74.5 years (p<0.0001). History of hypertension (p=0.005), systolic/diastolic blood pressure (p<0.0001) use of statin medication (p=0.02), smoking, alcohol consumption, history of ischaemic heart disease (p<0.0001) and stroke (p=0.005) were all statistically significantly different in the groups with the INES participants having the healthier lifestyle. BMI was not different between the groups (p=0.603). Analysis of vascular calibre in the subset of age-matched individuals indicated that the diameter of the superior and inferior retinal veins and arteries were all significantly smaller in the INES participants (p<0.0001).

 

Conclusions:

 

The results show that as predicted the INES population are healthier despite being older. A healthier lifestyle with a reduced prevalence of cardiovascular risk factors was associated with smaller retinal vessel diameters when compared with the general population.

 

Keywords: clinical (human) or epidemiologic studies: risk factor assessment • clinical research methodology • imaging/image analysis: clinical