Are Features Of The Metabolic Syndrome Associated With Macular Thickness In Individuals Without Diabetes Mellitus?

1. Roland Ling¹
2. Angela Shore²
3. Hirut von Lany¹
4. John Tooke²
5. Kim Gooding²

¹West of England Eye Unit, Royal Devon and Exeter NHS Foundation Trust, Exeter, EX2 5DW
²Institute of Biomedical and Clinical Science, Peninsula Medical School and Peninsula National Institute of Health Research Clinical Research Facility, Exeter, EX2 5AX

Retinal vascular morphological abnormalities have been described in individuals with the metabolic syndrome. However, the impact of the metabolic syndrome on macular thickness is not known.

Purpose: Examine whether features of the metabolic syndrome (waist, mean arterial pressure (MAP), fasting levels of glucose, triglycerides and HDL-cholesterol) are associated with macular thickness in non-diabetic individuals.

Methods: 50 individuals were recruited (age range:26-78years, 25 men). Thickness was assessed in the 9 subdivisions of the macular by optical coherence tomography.

Results: Fovea thickness was within the normal range for all participants. Waist was 94.4(15.8)cm (mean(SD)), MAP: 91.4(11.1) mmHg; glucose: 4.9(0.5)mmol/l; triglycerides: 1.19(0.46)mmol/l; HDL-cholesterol: 1.54(0.42)mmol/l. Initial correlation analysis (Pearson's) demonstrated that MAP was associated with mean thickness of the inner macular quadrants (r=0.287,p=0.046) but not with fovea. No such associations were observed with the other metabolic parameters. Further analysis revealed that MAP, adjusted for waist, glucose, triglycerides and HDL, was positively associated with each inner and outer quadrant of the macular (inner quadrants: standardised beta range: 0.433-0.512, p value range: 0.008-0.028; outer quadrants: r=0.346-0.434, p=0.021-0.071, forced regression analysis). Capillary pressure may account for this observed relationship as MAP was no longer significantly associated with macular thickness when both MAP and capillary pressure were entered into forced regression analysis.

Conclusions: This study has shown that MAP is positively associated with macular thickness with the exception of the fovea, however, none of the other features of the metabolic syndrome were associated with macular thickness in these non-diabetic individuals.