de Fine Olivarius et al. BMC Public Health 2011, 11:80 http://www.biomedcentral.com/1471-2458/11/80 Table 4 Prevalence of diabetic retinopathy at diabetes diagnosis and at 6-year follow up Diabetic retinopathy at 6-year follow upa Diabetic retinopathy at diabetes diagnosisa No diabetic retinopathy Background retinopathy No diabetic retinopathy 680 (88.3) Background retinopathy Microaneurysms only Without maculopathy With maculopathy Proliferative retinopathy Total 2 (20.0) 8 (47.1) 0 (0) 0 (0) 690 (86.0) Microaneurysms only 46 (6.0) Without maculopathy 32 (4.2) With maculopathy 10 (1.3) Proliferative retinopathyb 2 (0.3) 3 (30.0) 1 (5.9) 1 (20.0) 0 (0) 51 (6.4) 4 (40.0) 3 (17.6) 0 (0) 0 (0) 39 (4.9) 1 (10.0) 1 (5.9) 3 (60.0) 0 (0) 15 (1.9) 0 (0) 4 (23.5) 1 (20.0) 0 (0) 7 (0.9) Page 9 of 13 Total 770 (96.0) 10 (1.2) 17 (2.1) 5 (0.6) 0 (0) 802 (100) Data are numbers (row- and column-%). aRefers to the eye with the most pronounced diabetic retinopathy at diabetes diagnosis and 6-year follow up, respectively. bAmong these, 2 patients with new vessels on the optic disc. that the detection rate for eye disease was higher in patients with low visual acuity. This may have biased the cross-sectional associations between eye disease and visual acuity in Table 2 and 5, but it does not to the same extent compromise the estimation of the predic- tive power of the eye pathologies at diagnosis for the change in visual acuity during the following 6 years. Therefore, our non-standardized estimation of eye pathologies at diabetes diagnosis only diminishes our ability to detect an effect of these variables on changes in visual acuity. Table 5 Visual acuity and retinopathy 6 years after diabetes diagnosis Retinopathya Diabetic retinopathy Microaneurysms only Further diabetic retinopathy b Age-related macular degeneration, AMD Visual acuitya Normal n = 734 46 (6.3) 48 (6.5) Moderately Blind impaired n = 54 n = 16 All patients n = 804 5 (9.3) 10 (18.5) 0 (0) 51 (6.3) 3 (18.8) 61 (7.6) 65 (8.9) 20 (37.0) 11 (57.9) 96 (11.9) Other retinopathy 44 (6.0) 0 (0) 2 (10.5) 46 (5.7) No retinopathy 541 (73.7) 23 (42.6) 1 (6.3) 565 (70.3) Data are numbers (column-%). aRefers to best seeing eye. bAmong patients with normal eye sight, impaired eye sight and blindness there are 4, 2 and 1 patient, respectively, with proliferative retinopathy. Comparison with existing literature Predictors of 6-year visual loss In Table 2 and in most studies [3-9,34-36] the main eye pathology is assigned as the cause of visual impairment. We analysed prospectively 26 possible ocular and non- ocular predictors of vision loss (Table 1). It is striking that, besides age and triglycerides, only DR, AMD, and cataract, many of which are surgically modifiable, were associated with declining vision over 6 years. This was observed even though the measurement error in the estimation of these eye pathologies is considered to be greater than for many of the other possible predictors. In follow up studies, the association between baseline DR or AMD and later impaired vision is well documen- ted [14-16,19], and AMD may cause deterioration in visual acuity earlier in diabetic patients than in non- diabetic people though the prevalence of AMD does not seem to differ markedly between the two groups [17]. Furthermore, diabetic subjects have a 2 to 4 times greater risk of developing cataract than non-diabetic people [18]. As our way of collecting information about glaucoma may underestimate the true prevalence of glaucoma in our patients, we were not able to analyse the predictive effect of glaucoma for visual loss. The possible impor- tance of eye pressure for the change in eye sight over 6 years is, however, indicated by the non-significant tendency reported in Table 1. Only a few prospective studies have assessed non- ocular predictors of visual loss other than age and sex [14,16,19-23]. The only study including more than a few possible predictors used a subjective measure of visual dysfunction [14], while the most comprehensive study until now using measured visual acuity examined the