Abstract
Abstract: :
Purpose: Diabetes mellitus and systemic hypertension are frequently reported as ischemic causes of sixth nerve palsy/paresis, but we are unaware of rigorous controlled studies that have established this association. We conducted a population-based case-control study to determine the presence and magnitude of any association of pre-existing diabetes mellitus and systemic hypertension with sixth nerve palsy. Methods: Using the Rochester Epidemiology Project medical records-linkage system, which captures virtually all medical care provided to residents of Olmsted County, MN, USA, we had previously identified all incident cases of sixth nerve palsy/paresis (n=132) among county residents between January 1, 1978 and December 31, 1992 (ARVO 2002, # 1485). In the present study, we identified an equal number (n=132) of randomly selected controls from the same population, matched for age, sex and length of medical follow-up. We reviewed the entire medical record of each case and control, using stringent predetermined criteria to define the presence of diabetes mellitus and systemic hypertension. We compared the incidence of diabetes and systemic hypertension between cases and controls by using Chi-square tests, and we calculated odds ratios (OR) with 95% confidence intervals (CI). Results: Diabetes mellitus occurred more frequently in cases (n=18, 13.6%) than in controls (n=6, 4.5%; P=0.01, OR=3.32, 95% CI=1.27-8.64). Systemic hypertension was equally common in cases (n=39, 29.5%) and controls (n=38, 28.8%; P=0.89, OR=1.04, 95% CI=0.61-1.76). Coexistent diabetes mellitus and systemic hypertension was more common in cases (n=14, 10.6%) than in controls (n=3, 2.3%; P=0.006, OR=5.10, 95% CI=1.43-18.20). Conclusions: Based on the results of this population-based study, we conclude that diabetes is associated with a 3-fold increased risk of sixth nerve palsy, whereas systemic hypertension does not appear to be associated with such an increased risk. In contrast, coexistent diabetes and systemic hypertension is associated with a 5-fold increased risk. The much cited association of systemic hypertension alone with sixth nerve palsy appears to be coincidental.
Keywords: clinical (human) or epidemiologic studies: ris • neuro-ophthalmology: diagnosis • esotropia and exotropia