4 Systemic and Ocular Factors Influencing Diabetic Retinopathy |
91 |
|
|
has not been reported and is fraught with concerns for adverse side effects for the fetus.
4.2.10 Other Systemic Factors
There are many other systemic factors that have been hypothesized to influence diabetic retinopathy. These factors are generally considered to have lesser impact, and in a number of cases the scant evidence available suggests that they have no impact. The waist-to-hip
ratio has been associated with a higher incidence of DR and DME.19,108 Use of diuretics, lower serum
albumin, higher serum von Willebrand factor, and
lower plasminogen activator inhibitor level have all been associated with worse DR.58,38 Less alcohol con-
sumption and hypomagnesemia have been associated with worse DR.58,109 Lower serum growth hormone
has been associated with relative protection from DR.110 Factors that have not been found to have an
association with aspects of diabetic retinopathy include elevated total cholesterol7,36,58–60,12, HDLcholesterol19,58,60,12, LDL cholesterol61, non-HDL
cholesterol19, lipoprotein (a)58, serum creatinine12, frequency of exercise5, smoking11,5,7,13,19,49,58,60, use
of aspirin13, hematocrit58, white blood cell count58,
platelet count58, use of beta blockers58, serum fibrinogen38,60, and diabetic neuropathy49.
In several cases, the evidence for associations is
inconsistent as for example in the case of hyperhomocysteinemia111,112,113. Table 4.3 shows selected
characteristics inconsistently associated with DR across studies.
4.2.11 Influence on Visual Loss
The influence of systemic factors on visual loss, summarized by the index doubling of the visual angle, is shown in Table 4.4. All of these data derive from
Table 4.3 Inconsistent relationships of various systemic factors to prevalence, incidence, or severity of diabetic retinopathy
Factor |
Positive association reported |
No association detected |
Body mass index |
11 |
12;5;13;19;19;24;50;58;60 |
Serum triglycerides |
38 |
7;19;59;60 |
Systolic BP |
38;36;58 |
12 |
Diastolic BP |
12 |
38;58 |
Proteinuria (higher prevalence) |
11;59 |
5;7;59 |
Presence of macrovascular disease |
58 (stroke) 38 (amputation) |
5, 49;58 (CAD) 11;38 (stroke, CABG) 59 |
Hyperhomocysteinemia |
111 |
112;113 |
|
|
|
Factors in the left-hand column have been tested for an association with presence of or severity of diabetic retinopathy. Columns 2 and 3 list studies that report a positive association or lack of an association, respectively. Results of multivariate testing were taken if the univariate and multivariate results were discordant. BP ¼ blood pressure; CAD ¼ coronary artery disease; CABG ¼ coronary artery bypass grafting.
Table 4.4 Influence of Systematic Factors on Doubling of the Visual Angle in Three Types of Diabetes Mellitus
|
Younger onset |
Older onset, taking insulin |
Older onset, not taking insulin |
Increasing baseline HbA1C |
X |
X |
(X) |
Higher SBP |
X |
X |
|
Higher DBP |
X |
|
X |
Proteinuria |
X |
X |
|
Smoking history |
|
|
X |
Smoking pack years |
X |
|
X (but in a paradoxical direction) |
DME |
X |
X |
X |
Retinopathy severity |
X |
X |
X |
|
|
|
|
Data for visual impairment are similar to data for doubling of visual angle for each group. Empty cells mean no association was found on univariate analysis. A black X means that an association was found on univariate analysis. A red X means that the association persisted in a multivariate analysis. The analyses at 10 and 14 years were similar in results, but in the few cases where they differed, the 14-year results are shown. The parenthesis means that the association was present on multivariate analysis only. All data from Moss114.