Table 1

Clinical characteristics at baseline eye assessment in UK Biobank (2009–2013) and from the third health check phase for EPIC-Norfolk (2004–2011)

Baseline characteristicMean (SD) or (%)
UK Biobank N=66 326EPIC N=5955
Median duration of follow-up (years)7.79.1
Age (years)56.8 (8.2)67.6 (7.6)
Female (%)55.0%57.1%
Ethnicity (%)
 White92.0%99.5%
 Black2.5%0.1%
 Asian2.5%0.0%
 Other2.5%0.2%
 Unknown/did not answer0.6%0.0%
Smoking (%)
 Never smoker56.7%49.7%
 Occasionally2.6%N/A
 Ex-smoker34.0%44.2%
 Current smoker6.1%4.5%
 Prefer not to say/missing0.5%1.6%
BMI (kg/m²)27.2 (4.7)26.8 (4.3)
Systolic BP (mm Hg)136.8 (18.3)135.7 (16.6)
Diastolic BP (mm Hg)81.5 (10.0)78.5 (9.3)
Total cholesterol (mmol/L)5.7 (1.1)5.4 (1.1)
LDL cholesterol (mmol/L)3.5 (0.9)3.2 (1.0)
HDL cholesterol (mmol/L)1.5 (0.4)1.5 (0.4)
Triglycerides (mmol/L)1.7 (1.0)1.7 (0.9)
UK BiobankEPIC
Image quality*0.9 (0.1)0.9 (0.1)
Arteriolar width (µm)86.9 (7.9)75.1 (6.4)
Venular width (µm)103.1 (13.0)91.4 (10.8)
Arteriolar tortuosity†4.4 (1.6)4.3 (1.6)
Venular tortuosity†3.1 (1.4)3.2 (1.3)
Arteriolar vessel area (mm²)1.8 (0.8)2.0 (0.7)
Venular vessel area (mm²)2.5 (0.9)2.6 (0.7)
Arteriolar segment SD−1 (µm−1)0.08 (0.03)0.13 (0.03)
Venular segment SD−1 (µm−1)0.10 (0.03)0.14 (0.04)
Use of medications
 Blood pressure lowering19.6%35.1%
 Cholesterol lowering17.9%22.3%
 Prefer not to report/missing1.2%N/A
Self-reported history
 Heart attack (%)1.9%3.1%
 Stroke (%)1.4%2.0%
 Prefer not to report/missing1.2%N/A
 Diabetes (%)4.9%4.0%
  • Values are mean (SD) or (%).

  • Missing data were BMI n=287, blood pressure n=207 in UK Biobank only. Framingham risk score-based models for incident MI that used lipids missing data were as follows after excluding those with prevalent events (MI or diabetes) or using lipid lowering therapy, n= 6805 for total cholesterol or HDL cholesterol for UK Biobank. Other missing variables for UK Biobank were LDL cholesterol n=4628; triglycerides n=4576; and for EPIC-Norfolk—total cholesterol n=428, LDL cholesterol n=510, HDL cholesterol n=427, triglycerides n=428)

  • *Image quality score generated by QUARTZ, values range from 0.6 to 1.0, higher values indicate higher image quality.

  • Geometric mean exponentiated SD of the log-transformed values; the 95% range for the geometric mean is from (geometric mean÷GSD2) to (geometric mean×GSD2).

  • BMI, body mass index; BP, blood pressure; EPIC, European Prospective Investigation into Cancer; HDL, high-density lipoprotein; LDL, low-density lipoprotein; QUARTZ, QUantitative Analysis of Retinal vessels Topology and siZe.