| Abstract | Uvod: Utjecaj opstrukcijske apneje tijekom spavanja (engl. Obstructive Sleep Apnea, OSA) na koštani metabolizam i razvoj osteoporoze nedovoljno je istraživana tema u kojoj i dalje postoje mnoge nedoumice. Unatoč ispitivanju različitih markera u brojnim studijama, dosad u ovoj populaciji nisu istražene uloge važnih parametara povezanih s koštanim zdravljem – indeksa trabekularne kosti (TBS), koji predstavlja neizravni indeks koštane miroarhitekture, te inaktivnog oblika matriks Gla proteina (dp-ucMGP), važnog inhibitora vaskularne mineralizacije. Cilj ove disertacije bio je ispitati razlike u parametrima denzitometrijskog snimanja, TBS indeksa, markera koštane pregradnje i dp-ucMGP-a između OSA pacijenata i usklađene kontrolne skupine.
Ispitanici i metode: U ovo istraživanje su uključena ukupno 53 muška pacijenata s novodijagnosticiranom OSA-om, uz 50 kontrolnih ispitanika usklađenih prema dobi i antropometrijskim mjerama s ispitivanom skupinom. Svi uključeni sudionici bili su podvrgnuti uzimanju detaljne medicinske anamneze i dnevnih navika, denzitometrijskom snimanju uz procjenu TBS indeksa, te uzorkovanju krvi za biokemijsku analizu.
Rezultati: Prosječni apneja-hipopneja indeks (AHI) OSA ispitanika bio je 43,8±18,8 epizoda/sat. OSA pacijenti su imali statistički značajno više plazmatske razine dp-ucMGP-a u usporedbi s kontrolnom skupinom (512,7±71,9 vs. 465,8±50,9 pmol/L; P<0,001). Ispitivana i kontrolna skupina nisu se značajno razlikovale u odnosu na standardne denzitometrijske rezultate, dok su vrijednosti TBS indeksa bile značajno niže u OSA skupini (1,24±0,17 vs. 1,36±0,15; P<0,001). Multipla linearna regresija je pokazala da je AHI indeks bio značajni neovisni prediktor dp-ucMGP koncentracija (β±SE; 1,461±0,45; P=0,002), dok je TBS indeks zadržao značajnu povezanost s dp-ucMGP vrijednostima (β±SE; -93,77±38,1; P=0.001). Analiza dijagnostičkih performansi TBS indeksa je pokazala da se granična vrijednost od <1,305 može upotrijebiti za otkrivanje pozitivnog OSA statusa, uz osjetljivost testa od 75,5% i specifičnost od 80,0%. Također, multivarijatna logistička regresija je pokazala da su TBS (OR 0,001; P=0,002) i dp-ucMGP (OR 1,01; P=0,019) neovisni i značajni prediktori pozitivnog OSA statusa.
Zaključak: Istraživanje je pokazalo da su razine dp-ucMGP-a značajno veće u OSA pacijenata u usporedbi s kontrolnim ispitanicima, te da pozitivno koreliraju s AHI indeksom. Nadalje, TBS indeks je značajno niži u OSA populaciji, te negativno korelira s AHI indeksom, dok se vrijednosti standardnih denzitometrijskih parametara nisu značajno razlikovale između ispitivanih skupina. |
| Abstract (english) | Introduction: The impact of obstructive sleep apnea (OSA) on bone metabolism and development of osteoporosis is an under-researched topic in which remains controversial. Despite examining various markers in numerous studies, the role of important parameters related to bone health have not been investigated so far in this population - trabecular bone score (TBS) results, which represents degree of degradation of bone microarchitecture, and inactive matrix Gla protein (dp-ucMGP), an important inhibitor of vascular mineralization. The aim of this dissertation was to examine differences in densitometric imaging parameters, TBS scores, bone remodeling markers, and dp-ucMGP between OSA patients and a matched control group.
Subjects and Methods: A total of 53 male patients with newly diagnosed OSA were included in this study, with 50 controls matched in age and anthropometric parameters with the study group. All of the participants were subjected to detailed medical interview and daily habits questioning, densitometric imaging with TBS calculation, and blood sampling for biochemical analysis.
Results: The mean apnea-hypopnea index (AHI) of OSA subjects was 43.8 ± 18.8 episodes / hour. OSA patients had statistically significantly higher plasma levels of dp-ucMGP compared with the control group (512.7 ± 71.9 vs. 465.8 ± 50.9 pmol / L; P <0.001). OSA and control groups did not significantly differ in standard densitometric results, while TBS scores were significantly lower in the OSA group (1.24 ± 0.17 vs. 1.36 ± 0.15; P <0.001). Multiple linear regression indicated that AHI was a significant independent predictor of dp-ucMGP concentrations (β ± SE; 1.461 ± 0.45; P = 0.002), while TBS maintained a significant association with dp-ucMGP values (β ± SE; -93.77 ± 38.1; P = 0.001). An analysis of the diagnostic performances of TBS scores showed, that a cut-off value of <1,305 could be used to detect positive OSA status, with test sensitivity of 75.5% and specificity of 80.0%. Furthermore, multivariate logistic regression showed that TBS score (OR 0.001; P = 0.002) and dp-ucMGP (OR 1.01; P = 0.019) were independent and significant predictors of positive OSA status.
Conclusion: This dissertation showed that dp-ucMGP levels were significantly higher in OSA patients compared to controls and correlated positively with AHI index. Furthermore, TBS score was significantly lower in the OSA population, and negatively correlated with AHI index, while the values of standard densitometric parameters did not significantly differ between the study groups. |
