Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

[EX Q]: Vitamin D is associated with a number of inflammatory diseases and plays a significant role in regulating bone metabolism. Serum calcifediol was demonstrated to be potentially associated with periodontal disease. The purpose of this study was to evaluate whether an association exists between plasma calcifediol concentrations and aggressive periodontitis (AgP) and whether plasma levels of bone-related biomarkers (osteocalcin, alkaline phosphatase, calcium, and phosphorus) regulated by vitamin D are related to AgP.', 'Sixty-six patients with generalized AgP, 52 patients with chronic periodontitis, and 60 healthy controls were included in this study. Periodontal examination consisted of probing depth, attachment loss, and bleeding index measurements. Hematic calcifediol and bone-related biomarker levels were detected using radioimmunity assay kits or a biochemical analyzer.', 'Plasma calcifediol levels in patients with AgP were higher than those of healthy controls (29.28 versus 21.60 nmol/l; P <0.05) and were statistically significantly correlated with bleeding index (r = 0.321; P <0.05). Plasma osteocalcin concentrations in patients with AgP were higher than those of healthy controls (0.90 versus 0.70 ng/ml; P <0.05). Serum inorganic phosphorus values of both periodontitis groups were lower than those of healthy controls (1.06 +/- 0.18 mmol/l and 1.10 +/- 0.15 mmol/l versus 1.26 +/- 0.17 mmol/l; P <0.05).
[EX A]: Is elevated plasma calcifediol associated with aggressive periodontitis?

[EX Q]: It is a matter of debate whether or not ordinary heading of the ball in soccer causes injury to brain tissue.', 'To analyse concentrations of the biochemical markers of brain tissue damage S-100B and neurone specific enolase (NSE) in serum of female elite soccer players in association with a competitive game.', 'Venous blood samples were obtained from 44 female soccer players before and after a competitive game for analysis. The number of headers and trauma events (falls, collisions, etc) was assessed from videotape recordings for each player.', 'Concentrations of both brain damage markers were increased after the game (S-100B, 0.18 (0.11) v 0.11 (0.05) microg/l (p = 0.000); NSE, 10.14 (1.74) v 9.05 (1.59) microg/l (p = 0.001)). There was a significant correlation between changes in S-100B concentrations and both the number of headers (r = 0.430, p = 0.004) and the number of other trauma events (r = 0.517, p < 0.001).
[EX A]: Are serum concentrations of two biochemical markers of brain tissue damage S-100B and neurone specific enolase increased in elite female soccer players after a competitive game?

[EX Q]: The timing of CEA for symptomatic internal carotid artery (ICA) stenosis remains a matter of controversy. Recent registry data showed a significantly increased risk, especially in the very early days after the onset of symptoms. In this study the outcome of CEA in the hyperacute phase has been investigated.', 'The outcome of CEA for symptomatic ICA stenosis between January 2004 and December 2013 has been retrospectively analyzed. Patients were divided into four timing groups: surgery within 0 and 2 days, between 3 and 7 days, 8 and 14 days, and thereafter. The post-operative 30 day stroke and death rates were assessed.', 'A total of 761 symptomatic patients (40.1% with transient ischemic attack [TIA], 21.3% with amaurosis fugax, and 38.6% with ischemic stroke) were included, with an overall peri-operative stroke and death rate of 3.3%. A stroke and death rate of 4.4% (9/206) for surgery within 0 and 2 days, 1.8% (4/219) between 3 and 7 days, 4.4% (6/136) between 8 and 14 days, and 2.5% (5/200) in the period thereafter (p\xa0=\xa0.25 for the difference between the groups) was observed. The timing of surgery did not influence the peri-operative outcome in a multivariate regression analysis (OR 0.93 [0.63-1.36], p\xa0=\xa0.71).
[EX A]:
Does very urgent carotid endarterectomy increase the procedural risk?