Reduced incidence of blindness in relation to diabetes mellitus in southern Germany?

AIMS: We estimated the incidence of blindness in the diabetic and non-diabetic population in 2008 and compared it with results from 1990-1998 in a neighbouring region.
METHODS: All newly registered blindness allowance recipients in 2008 were drawn up in a German region (population 4.5 million). We estimated sex-specific, age-specific and standardized incidence rates of blindness in the diabetic and the non-diabetic population and relative and attributable risks as a result of diabetes. A comparison to the data from 1990-1998 was performed using log-linear Poisson regression.
RESULTS: Four-hundred and sixty-eight cases were drawn up (63% female). One-hundred and twenty-two (26.1%) had diabetes. Blindness incidence rates (per 100, 000 person-years) standardized to the 2008 German population were: men 9.1 (95% confidence interval 7.8-10.5), women 9.9 (8.8-11.1); diabetic population: men 21.8 (11.6-31.9), women 19.7 (9.2-30.1); non-diabetic population: men 8.0 (6.6-9.5), women 9.1 (7.9-10.3). Relative risk of blindness, diabetic vs. non-diabetic population: men 2.7 (1.6-4.5), women 2.2 (1.3-3.8). Attributable risk among exposed: 63% in men, 54% in women. Population attributable risk: 12% in men, 8% in women. Incidences of blindness were significantly lower than in all years of the period 1990-1998 in both the diabetic and the non-diabetic population.
CONCLUSIONS: We found the incidence of blindness to be approximately 2.5-fold higher in the diabetic compared with the non-diabetic population. Fifty-eight per cent of the risk to become blind in diabetic individuals and 9% of the risk to become blind in the entire population were attributable to diabetes. The decrease of the blindness incidence observed during the 1990s may have continued.