Blue eyes as a risk factor for type 1 diabetes

Enrico Di Stasio, Daria Maggi, Enzo Berardesca, Georgiana Clare Marulli, Carla Bizzarri, Angelo Lauria, Rosalba Portuesi, Maria Gisella Cavallo, Francesco Costantino, Raffaella Buzzetti, Elisa Astorri, Dario Pitocco, Marco Songini, Paolo Pozzilli

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)609-613
Number of pages5
JournalDiabetes/Metabolism Research and Reviews
Issue number6
Publication statusPublished - Sep 2011


  • Latitude
  • Skin type
  • Type 1 diabetes
  • Type 1 diabetes risk
  • Vitamin D

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism
  • Internal Medicine


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