Osteoprotegerin in Turner syndrome - relationship to aortic diameter

Cardiovascular disease is a cardinal trait of Turner syndrome (TS), causing half of the threefold excess mortality. As osteoprotegerin (OPG) is a potential biomarker of cardiovascular disease, this cross-sectional and prospective study aimed at elucidating OPG levels in TS and its relationship to aortic diameter as well as validated cardiovascular risk markers.

Adult women with TS (n = 99) were examined thrice (mean follow-up 4·7 ± 0·5 years), and 68 age-matched healthy female controls were examined once. Aortic diameter was assessed by cardiovascular magnetic resonance. Twenty-four-hours blood pressure monitoring and biochemical assessments were also performed.

Osteoprotegerin levels (median with range) were lower in TS (777 [326-10 569] ng/l) compared with controls (979 [398-1987] ng/l; P < 0·05) and did not change during follow-up. The OPG concentration was higher among women with TS older than 50 years of age (996 [542-4996] vs 756 [326-10 569] ng/l; P < 0·05) with a trend towards a higher OPG in TS who were on antihypertensive medication (938 [490-2638] vs 752 [326-10 569] ng/l; P = 0·09). Contrary to controls, OPG levels correlated with BSA-indexed aortic diameter (r = 0·31-0·45; P < 0·05), age (r = 0·29; P < 0·05) and high-sensitivity C-reactive protein (r = 0·23; P = 0·02) and inversely with BSA (r = -0·20; P < 0·05), weight (r = -0·23; P < 0·05) and plasma oestradiol levels (r = -0·34; P < 0·05).

Levels of OPG are lower in TS and correlate with aortic diameter, age, BSA, weight and oestradiol in TS, but not controls. Future studies are needed to assess whether OPG may serve as a biomarker of aortic or cardiovascular disease in TS.