Mads Nybo and Lars M Rasmussen
Osteoprotegerin (OPG) strongly inhibits bone resorption and may also serve as a vascular calcification inhibitor. However, recent studies have indicated that high plasma OPG is a strong predictor of cardiovascular disease (CVD) and mortality. To evaluate this capability, the data concerning OPG as a CVD predictor was gathered through a systematic literature review.
Design and methods
Studies investigating OPG as a predictor of CVD or mortality were extracted from Medline and the Cochrane Library, retrieving 187 articles. Non-relevant articles were excluded, resulting in a total of 45 articles. After thorough evaluation of the abstracts, only eight prospective studies containing a follow-up period with a clinical emphasis on CVD were eligible for the literature review.
All studies except one confirmed that OPG measurement adds important prognostic information to the existing markers of CVD and mortality in high-risk populations. Hazard ratios emphasized the significant correlation between plasma OPG concentration and mortality. Due to methodological problems (e.g., population investigated, measurement principle, and statistics performed), meta-analysis could not be performed. As only one study was conducted in a healthy cohort, the results cannot per se be extrapolated to the general population.
The combined results support plasma OPG as an independent predictor of CVD and mortality in high-risk populations. However, more longitudinal studies in general cohorts are needed before the use of plasma OPG can be evaluated in this regard.
Gitte Maria Jørgensen, Birgitte Vind, Mads Nybo, Lars Melholt Rasmussen and Kurt Højlund
Osteoprotegerin (OPG) is a soluble tumour necrosis factor-receptor-like molecule present in connective tissues, especially bone and vasculature. It is known to accumulate in the arterial wall in diabetes. As its synthesis in vascular cells is decreased by insulin, we wanted to elucidate the acute effects of insulin on plasma OPG concentrations in individuals with type 2 diabetes and obese individuals compared with lean controls.
The study population consisted of ten type 2 diabetic, ten obese subjects, and ten lean subjects with no family history of diabetes.
All subjects underwent a 4-h euglycemic–hyperinsulinemic clamp. Plasma OPG, insulin, lactate, HbA1c, cholesterol, triglycerides, free fatty acids (FFA), and glucose disposal rate were measured before and at the end of the clamp.
Baseline OPG concentrations did not differ significantly between groups. Insulin infusion decreased plasma OPG concentrations in all groups (P<0.01); however, the fall in OPG was 50% less in obese and type 2 diabetic individuals (P=0.007). Baseline OPG correlated with fasting insulin, baseline lactate, and low density lipoprotein cholesterol in the diabetic group, and with baseline FFA in the lean group. The relative change of OPG in response to insulin correlated inversely with HbA1c and baseline FFA in the lean group.
Acute hyperinsulinemia decreases plasma OPG, but with diminished effect in individuals with type 2 diabetes and obesity. Increased levels of OPG in arteries and plasma in diabetes together with the capability of plasma OPG as a cardiovascular risk predictor may be related to the described effects of insulin.
Kristian Hillert Winther, Steen Joop Bonnema, Frederik Cold, Birgit Debrabant, Mads Nybo, Søren Cold and Laszlo Hegedüs
Selenium is present in the active site of proteins important for thyroid hormone synthesis and metabolism. The objective of this study is to investigate the effect of selenium supplementation in different doses on thyroid function, under conditions of suboptimal dietary selenium intake.
The Danish PREvention of Cancer by Intervention with SElenium pilot study (DK-PRECISE) is a randomized, double-blinded, placebo-controlled trial. A total of 491 males and females aged 60–74 years were randomized to 100 μg (n=124), 200 μg (n=122), or 300 μg (n=119) selenium-enriched yeast or matching yeast-based placebo tablets (n=126). A total of 361 participants, equally distributed across treatment groups, completed the 5-year intervention period.
Plasma samples were analyzed for selenium and serum samples for TSH, free triiodothyronine (FT3), and free thyroxine (FT4) at baseline, and after 6 months, and 5 years of supplementation.
Plasma selenium concentrations increased significantly and dose-dependently in treatment groups receiving selenium (P<0.001). Serum TSH and FT4 concentrations decreased significantly and dose-dependently by 0.066 mIU/l (P=0.010) and 0.11 pmol/l (P=0.015), respectively, per 100 μg/day increase, with insignificant differences between 6 months and 5 years. No significant effects were found for FT3 and FT3:FT4 ratio.
In euthyroid subjects, selenium supplementation minutely and dose-dependently affects thyroid function, when compared with placebo, by decreasing serum TSH and FT4 concentrations. Based on these findings, selenium supplementation is not warranted under conditions of marginal selenium deficiency. However, a role for selenium supplementation in the treatment of autoimmune thyroid diseases is still unresolved.
Dorte Glintborg, Katrine Hass Rubin, Mads Nybo, Bo Abrahamsen and Marianne Andersen
The prevalence of type 2 diabetes is increased in polycystic ovary syndrome (PCOS), but the prevalence of other diseases is not clarified. We aimed to investigate morbidity and medicine prescriptions in PCOS.
A National Register-based study.
Patients with PCOS (PCOS Denmark and an embedded cohort; PCOS Odense University Hospital (OUH)) and one control population. Premenopausal women with PCOS underwent clinical and biochemical examination (PCOS OUH, n=1217). PCOS Denmark (n=19 199) included women with PCOS in the Danish National Patient Register. Three age-matched controls were included per patient (n=57 483).
Main outcome measures
Diagnosis codes and filled prescriptions.
The mean (range) age of the PCOS Denmark group and controls was 30.6 (12–60) years. Patients in PCOS Denmark had higher Charlson index, higher prevalence of diabetes, dyslipidemia, and hypertension than controls. PCOS was associated with a two times increased risk of stroke and thrombosis, whereas the risk of other cardiovascular diseases was not increased. Thyroid disease, asthma, migraine, and depression were more prevalent in PCOS Denmark vs controls, whereas fractures were rarer. Infertility was increased in patients compared with controls, but the mean number of births was higher in PCOS. Medicine prescriptions within all diagnosis areas were significantly higher in PCOS patients than in controls.
In PCOS OUH, polycystic ovaries (PCO) and irregular menses were associated with a more adverse metabolic risk profile, but individual Rotterdam criteria were not associated with cardiometabolic diagnoses.
Cardiometabolic and psychiatric morbidity were significantly increased in a Danish population with PCOS. Medical diseases are frequent also in young patients with PCOS.