No abstract

The increased calcium requirements in early pregnancy are not completely offset by increased intestinal calcium absorption caused by high 1,25(OH)2D since changes in bone markers indicated a negative bone balance. The rise in bone formation in late pregnancy may be initiated by a spike in IGF-I levels. The high bone turnover in lactating women may be related to high prolactin and PTH levels, low E2 levels and perhaps increased parathyroid hormone-related protein levels.

BackgroundVery few studies have investigated the determinants of circulating 25-hydroxyvitamin D (25[OH]D) in young adults (18–25 years old) using a set of variables that include lifestyle, sociodemographic, and anthropometric data. Our aim was to investigate the association between these variables and vitamin D status in a sample of untreated young adults.MethodsA total of 738 young adults were enrolled in a (June cross-sectional study 2012 to May 2014) and were recruited from educational institutions in the Copenhagen area. For multivariate logistic regression subjects was categorized based on 25[OH]D in serum into; vitamin D sufficiency (S-25[OH]D > 50 nmol/L), vitamin D insufficiency (25 nmol/L ≤ S-25[OH]D ≤ 50 nmol/L), vitamin D deficiency (S-25[OH]D < 25 nmol/L). Information on lifestyle factors and education was obtained by self-reported questionnaires.Results700 subjects with a valid measurement of S-25[OH]D and a completed questionnaire was analysed. 238 had vitamin D insufficiency, 135 had vitamin D deficiency of which 13 had severe vitamin D deficiency (S-25[OH]D < 12.5 nmol/L). The relative risk (RR) for vitamin D deficiency was highest for men 2.09 (1.52, 2.87); obese subjects 2.00 (1.27, 3.15); smokers 1.33 (1.02, 1.73); subjects who exercised 0-½ hours a week 1.88 (1.21, 2.94); and subjects who consumed fast food once a week 1.59 (1.05, 2.43). The relative risk was significantly lower for subjects who were studying for a Bachelor’s degree (0.40 (0.23, 0.68). For vitamin D insufficiency, the highest RR was again for men 1.31 (1.06, 1.61); obese subjects 1.57 (1.17, 2.11); and subjects who exercised 0-½ hours a week 1.51 (1.11, 2.06).ConclusionIn this study of young adults, vitamin D deficiency was highly prevalent. Modifiable factors such as smoking, maintenance of normal BMI, and physical activity are all potential targets for interventional trials to determine the causal order; such knowledge would be useful in improving S-25[OH]D in young adults. The small group with severe vitamin D deficiency warrants increased attention.

No abstract

One of best validated findings in schizophrenia research is the association between blockade of dopamine D2 receptors and the effects of antipsychotics on positive psychotic symptoms. The aim of the present study was to examine correlations between baseline striatal D2/3 receptor binding potential (BPp) values and treatment outcome in a cohort of antipsychotic-naïve first-episode schizophrenia patients. Additionally, we wished to investigate associations between striatal dopamine D2/3 receptor blockade and alterations of negative symptoms as well as functioning and subjective well-being. Twenty-eight antipsychotic-naïve schizophrenia patients and 26 controls were included in the study. Single-photon emission computed tomography (SPECT) with [123I]iodobenzamide ([123I]-IBZM) was used to examine striatal D2/3 receptor BPp. Patients were examined before and after 6 weeks of treatment with the D2/3 receptor antagonist amisulpride. There was a significant negative correlation between striatal D2/3 receptor BPp at baseline and improvement of positive symptoms in the total group of patients. Comparing patients responding to treatment to nonresponders further showed significantly lower baseline BPp in the responders. At follow-up, the patients demonstrated a negative correlation between the blockade and functioning, whereas no associations between blockade and negative symptoms or subjective well-being were observed. The results show an association between striatal BPp of dopamine D2/3 receptors in antipsychotic-naïve first-episode patients with schizophrenia and treatment response. Patients with a low BPp have a better treatment response than patients with a high BPp. The results further suggest that functioning may decline at high levels of dopamine receptor blockade.