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Blue eyes as a risk factor for type 1 diabetes
Author(s) -
Di Stasio Enrico,
Maggi Daria,
Berardesca Enzo,
Marulli Georgiana Clare,
Bizzarri Carla,
Lauria Angelo,
Portuesi Rosalba,
Cavallo Maria Gisella,
Costantino Francesco,
Buzzetti Raffaella,
Astorri Elisa,
Pitocco Dario,
Songini Marco,
Pozzilli Paolo
Publication year - 2011
Publication title -
diabetes/metabolism research and reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.307
H-Index - 110
eISSN - 1520-7560
pISSN - 1520-7552
DOI - 10.1002/dmrr.1214
Subject(s) - medicine , incidence (geometry) , population , odds ratio , risk factor , type 1 diabetes , demography , confidence interval , diabetes mellitus , endocrinology , environmental health , physics , sociology , optics
Background A high frequency of blue eyes and fair skin are reported in northern European Caucasians with type 1 diabetes (T1D). Also there is an inverse relationship between latitude and T1D incidence. We determined whether iris colour and skin pigmentation are risk factors in a Caucasian population living in two Mediterranean regions located at the same latitude with higher ultraviolet B irradiance, but with different T1D incidence. Methods We studied iris colour in 281 consecutive subjects with T1D and 298 controls. Skin type was evaluated by melanin quantification. Results In Lazio, blue eyes and fair skin type are significantly more common in T1D subjects than in controls (21 versus 9%, p = 0.002; 50 versus 35%, p < 0.001, respectively). In Sardinia, the frequency of blue eyes in T1D subjects is twice that in controls (5.8 versus 2.6% and significantly higher when compared to the expected calculated frequency in the entire population). By logistic regression analysis, only blue eyes are independent and significant predictors of T1D [odds ratio for blue eyes = 2.2; 95% confidence interval (1.1–4.4), p = 0.019]. Conclusions As previously shown in a Caucasian population from northern Europe, blue eyes and a trend for fair skin increase the risk for T1D also in a Caucasian population born and residing in a Mediterranean region (Continental Italy). This finding may be relevant for explaining different T1D incidence as prevalence of blue eyes differ substantially between northern and southern European Caucasians. Copyright © 2011 John Wiley & Sons, Ltd.