The potential of cardiovascular risk factors for reducing visual impairment

Abstract

 

Purpose

 

Cardiovascular risk factors, in particular smoking and diabetes, are associated with increased risk for several major eye diseases (AMD, cataract, diabetic retinopathy, retinal vein occlusion…). However, their global impact on visual impairment has rarely been evaluated. The objective of the present study was to estimate the potential reduction in prevalence of visual impairment that would be obtained if the population was not exposed to several cardiovascular risk factors.

 

Methods

 

The POLA and Alienor studies are population-based studies on age-related eye diseases performed in Sète (France) in 1995-1997 (n=2510) and in Bordeaux (France) in 2006-2008 (n=814), respectively. In both studies, non refractive visual impairment was defined as a best-corrected visual acuity lower than 20/60 at best eye. Presence of cardiovascular risk factors was assessed through face-to-face interviews and specific measurements (weight, height, blood pressure, fasting plasma glucose and lipids). Smoking was defined as current or former smoking and diabetes as self-reported diabetes or fasting blood glucose≥7.0 mmol/L or nonfasting glycemia≥11.0 mmol/L or use of antidiabetic medication. Hypertension was defined as systolic blood pressure≥140mmHg or diastolic blood pressure≥ 90mmHg or antihypertensive treatment. Body mass index (BMI, in kg/m²) was calculated as weight/height². Multivariate Poisson regression models were constructed for estimating relative risks (RR) for cardiovascular risk factors, adjusting for socio-demographic characteristics. Population attributable fractions (PAF) were calculated and 95% confidence intervals (CI) derived from boostrapping.

 

Results

 

For the POLA study, PAF was 28.0% for smoking (95% CI: 14.3% - 41.5%) and 15.7% for diabetes (95 % CI: 5.7%- 25.4%). Similarly, in the Alienor study, PAF was 43.1% for smoking (95% CI: 8.4 % - 72.5 %) and 9.6 % for diabetes (95 % CI: -6.4 % - 30.1 %). Hypertension, BMI and plasma lipids were not significantly associated with visual impairment in both studies.

 

Conclusions

 

Together with diabetes, smoking appears as a major lever for reducing visual impairment. Along with the primary prevention strategies to reduce smoking in the general population, secondary prevention strategies should be considered, aiming at reducing visual impairment in smokers by adapting ophthalmological follow-up and treatments in smokers (and former smokers), as it is the case in diabetic subjects.