Malnutrition and retinal vascular caliber in the elderly: the POLA study

Abstract

Purpose: The pathway linking late-life malnutrition to greater risk of cardiovascular disease is unclear. Microcirulatory changes assessed by retinal vascular caliber have been linked with increased risk of stroke and coronary heart disease. The purpose of this study was to examine whether retinal vascular calibers are associated with malnutrition in elderly subjects free of cardiovascular diseases.

Methods: This was a cross-sectional analysis of a community-dwelling cohort comprising 1145 individuals aged 60 years and older. Retinal vascular caliber was measured from fundus photographs using a semiautomated, standardized imaging software. Malnutrition was assessed using body mass index (BMI) < 18.5 kg/m(2) and biomarkers of protein malnutrition: plasma albumin and transthyretin.

Results: In a multivariate model controlling for cardiovascular risk factors, retinal venular caliber was related to BMI (P = 0.0002) with an increased mean caliber for individuals with obesity and for those with low BMI. After multivariate adjustment for age, sex, hypertension, smoking, high-density lipoprotein (HDL) cholesterol, glomerular filtration rate and BMI, lower levels of albumin or transthyretin were associated with larger retinal venular caliber (P = 0.026 and P = 0.0018, respectively), that remain significant when adjusting for CRP (P = 0.040 and P = 0.0060, respectively) or orosomucoid (P = 0.034 and P = 0.0020, respectively). The relationships between retinal arteriolar caliber and BMI, albumin and transthyretin did not reach significance (P = 0.14, P = 0.12, and P = 0.15, respectively).

Conclusions: Protein malnutrition was identified as an additional factor associated with retinal venular dilatation beyond inflammation. This suggests that early microvascular changes may be one of the underlying mechanisms of increased risk of cardiovascular disease observed in elderly subjects suffering from malnutrition.

Keywords: albumin; elderly; malnutrition; microcirculation; retinal vessels; risk factors; transthyretin.