Association of Average Telomere Length with Body-Mass Index and Vitamin D Status in Juvenile Population with Type 1 Diabetes

Zdr Varst. 2015 Mar 13;54(2):74-8. doi: 10.1515/sjph-2015-0011. eCollection 2015 Jun.

Abstract

Background: Type 1 diabetes (T1D) is an autoimmune chronic disease where hyperglycemia, increased risk of oxidative stress, advanced glycation end-products and other genetic and environmental factors lead to T1D complications. Shorter telomeres are associated with hyperglycemic levels and lower serum vitamin D levels.

Methods: Average telomere length (ATL) in whole blood DNA samples was assessed with qPCR method in 53 Slovenian T1D children/adolescents (median age 8.7 years, 1:1.3 male/female ratio). Body mass index standard deviation score (BMI-SDS), glycated haemoglobin and serum level of vitamin D metabolite (25-(OH)-D3) and the age at the onset of T1D were collected from the available medical documentation.

Results: Results indicate shorter ATL in subjects with higher BMI-SDS when compared to those with longer ATL (0.455 ± 0.438, -0.63 ± 0.295; p=0.049). Subjects with higher BMI-SDS had lower serum vitamin D levels when compared to those with lower BMI-SDS (40.66 ± 3.07 vs. 52.86 ± 4.85 nmol/L; p=0.045). Vitamin D serum levels did not significantly differ between subjects with longer/shorter ATL.

Conclusion: T1D children/adolescents with shorter ATL tend to have higher BMI-SDS. Lower serum vitamin D levels were associated with higher BMI-SDS, while associations between vitamin D serum levels, age at the onset of T1D, glycated haemoglobin and ATL were not observed. Additional studies with more participants are required to clarify the role of the telomere dynamics in T1D aetiology and development of complications.

Izhodišče: Sladkorna bolezen tipa 1 (SBT1) je kronična avtoimunska bolezen, pri kateri hiperglikemija ter zvišana raven oksidativnega stresa in končnih produktov glikacije skupaj z genetskimi in okoljskimi dejavniki privedeta do nastanka diabetičnih zapletov. Krajše dolžine telomerov so povezane s hiperglikemičnimi epizodami in nižjimi serumskimi vrednostmi vitamina D.

Metode: Z metodo qPCR smo iz vzorcev DNK periferne krvi določili povprečne dolžine telomerov 53 slovenskim bolnikom s SBT1 (povprečna starost 8,7 leta, razmerje med dečki in deklicami 1:1,3). Indeks standardnega odklona indeksa telesne teže (BMI-SDS), vrednosti serumskega metabolita vitamina D – 25-hidroksikalcifediola (25-(OH)-D3), glikiran hemoglobin in starost preiskovancev ob izbruhu bolezni smo pridobili iz razpoložljive medicinske dokumentacije.

Rezultati: Rezultati nakazujejo krajše dolžine telomerov pri bolnikih z višjimi vrednostmi BMI-SDS (0,455 ± 0,438, −0,63± 0,295; p=0,049). Preiskovanci z višjimi vrednostmi BMI-SDS so imeli nižje vrednosti 25-(OH)-D3 kot preiskovanci z nižjimi vrednostmi BMI-SDS (40,66 ± 3,07 proti 52,86 ± 4,85 nmol/L; p=0,045). Vrednosti 25-(OH)-D3 niso statistično značilno različne pri preiskovancih z višjimi oziroma nižjimi povprečnimi dolžinami telomerov.

Zaključki: Otroci in mladostniki s SBT1 s krajšimi dolžinami telomerov imajo nekoliko višje vrednosti BMI-SDS. Nižje vrednosti 25-(OH)-D3 so povezane z višjim BMI-SDS. Povezav med serumskimi vrednostmi 25-(OH)-D3, starostjo bolnikov ob izbruhu bolezni, glikiranim hemoglobinom in povprečnimi dolžinami telomerov nismo zaznali. Za razjasnitev vloge telomerov v etiologiji, patogenezi in nastanku zapletov SBT1 bodo potrebne nadaljnje raziskave z večjim številom preiskovancev.

Keywords: average telomere length; body mass index; juvenile patients; type 1 diabetes; vitamin D.