Impact of visceral fat and pro-inflammatory factors on the pathogenesis of age-related macular degeneration

Previous studies have indicated that the immune system is involved in the pathogenesis of the AMD. Increased visceral fat, in addition, has a pro-inflammatory effect on the organism by producing or influencing different kinds of inflammatory factors. The aim of this study is to determine the relationship of body fat distribution in patients with age-related macula degeneration in comparison to a control group in the Austrian population.

In this case-control study, body weight and height, and body mass index (BMI) were measured for each subject in 54 patients with exudative AMD and compared to 46 gender- and age-matched healthy control subjects. Body composition and abdominal fat areas were measured using dual-energy X-ray absorptiometry (DEXA). Data on age, gender distribution, smoking history and systemic diseases, respectively, were compared. The inflammatory markers CRP, tumour necrosis factor-alpha (TNF-alpha), leptin, amyloid A, amyloid beta and interleukin-6 (IL-6) were assayed by ELISA (R&D).

DEXA revealed central-abdominal-to-total body fat ratio of 0.073 +/- 0.011 in AMD patients compared to 0.061 +/- 0.013 in the controls (p <0.001; d = 0.98). The calculation of BMI has provided a significant result (p =0.045). U-test results for Aß1-42, IL-6, SAA and CRP each were significant (p < 0.05), with higher values in AMD patients. Leptin, TNF-alpha and Aß1-40 showed no significant differences between the groups.

Our results suggest that abdominal fat distribution is significantly associated with age-related macular degeneration. Analysis of patients with exudative AMD revealed higher levels of CRP, amyloid ß1-42, IL-6 and amyloid alpha.