Çağla İŞMAN, Şebnem GÜLEN, Nimet GÜNDOĞAN

The relationship between digit ratio and circadian typology among medical students

Amaç: Sabahçıl-akşamcıl tercihi bireyler arasında gözlenen belirgin kronobiyolojik farklılıkların temel dayanağıdır. Bu çalışma fetal testosteron maruziyetinin sirkadyen tiopolojiye özgü seksüel dimorfizmdeki olası nedensel rolünü araştırmak üzere tasarlandı. Gereçler ve Yöntemler: Çalışmaya toplam 183 öğrenci (111 kadın, 72 erkek; ort. yaş 20.7) dahil edildi. Sirkadyen tip dağılımları Horne-Ostberg Sabahçıl-Akşamcıl Anketi'nin Türkçe versiyonu kullanılarak belirlendi. El parmak oranı (2D/4D) ise 0.01 mm hassasiyeti olan dijital kaliper kullanılarak elde edilen 2. ve 4. parmak uzunlukları oranlanarak hesaplandı. Bulgular: Sirkadyen tipoloji değerlendirildiğinde, ara tipin %54.6 (n=100), sabahçıl tipin %29.5 (n=54) ve akşamcıl tipin %15.8 (n=29) oranında temsil edildiği belirlendi. 2D/4D oranı her iki elde de, erkek öğrencilerde kadın öğrencilere göre belirgin şekilde daha düşük bulundu (p

Tıp fakültesi öğrencilerinde el-parmak oranı (2D/4D) ve sirkadyen tipoloji arasındaki ilişki

Objectives: Morningness-eveningness preference stands for interindividual chronobiological differences. This study was designed to investigate if prenatal testosterone exposure is a candidate for having a causal role in sexual dimorphism observed in circadian typology. Materials and Methods: A total of 183 students (111 females, 72 males; mean age 20.7 years) were involved in the study. Circadian typology was assessed using the Horne-Ostberg Morningness-Eveningness Questionnaire. Digit lenghts were measured with digital calipers and digit ratio (2D/4D) was calculated by dividing the length of the second digit by that of the fourth digit. Results: Circadian typology assessment revealed 54 morning-(29.5%), 100 intermediate-(54.6%) and 29 evening-(15.8%) type students. Digit ratio of both hands in males were significantly lower than females (p<0.001). Digit ratio for both hands in morningness trait were significantly higher than intermediate (p<0.001) and eveningness (p<0.05 for the left and p<0.01 for the right hand) traits. Morning type was more common among females (35.1% vs 20.8%; p<0.05). Higher digit ratio was significantly associated with the morning type for both of the hands in both genders. Conclusion: Prenatal testosterone exposure, represented by digit ratio (2D/4D) as a proxy marker, seems to have a causal role in sexual dimorphism observed in the circadian typology preferences.

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