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.

Example Input: Extranodal natural killer/T-cell lymphoma, nasal type (ENKTL), is an aggressive type of lymphoma whose standard treatment and validated prognostic model have not yet been defined.', 'CD30 expression was detected using immunohistochemistry in 96 ENKTL patients, and the data were used to evaluate its relationship with clinical features, treatment response and prognosis.', 'Expression of CD30 was detected in 31.2% of ENKTL patients, which was significantly correlated with B symptoms and elevated serum lactate dehydrogenase. The complete remission rate was not significantly different between CD30-positive and negative groups. After a median follow-up time of 31 months, 5-year overall survival (OS) and 5-year progression-free survival (PFS) rates in the CD30-positive group were both significantly lower than those in the CD30-negative group (34.1% vs. 64.4%, P=0.002, for 5 year-OS; 26.0% vs. 66.7%, P<0.001, for 5 year-PFS). In patients with an International Prognostic Index (IPI) or Korean Prognostic Index (KPI) score of 0-1, CD30 positivity was associated with shorter 5-year OS and PFS (IPI: P=0.001 and 0.002, respectively; KPI: P=0.018 and 0.023, respectively). In a multivariate Cox regression model, CD30 expression and stage were independent prognostic factors for OS (p=0.004 and p=0.012, respectively) and PFS (p=0.001 and p=0.022, respectively).
Example Output: Is cD30 expression a novel prognostic indicator in extranodal natural killer/T-cell lymphoma , nasal type?

Example Input: Although the majority of evidence does not support association between Helicobacter pylori infection and ischaemic heart disease, the nature of this relationship may differ when virulence of the infecting strains are examined.', 'The prevalence of IgG antibody evidence of infection with CagA positive stains of H. pylori was investigated in stored plasma samples from 259 cases of myocardial infarction (aged 25-70 years, 74 males) and 259 population based controls from the same area in Northern Ireland. Two-hundred and seventy (52.1%) subjects were seropositive for anti-CagA IgG. CagA seropositivity was more common in cases than in controls: 56.4 vs 47.9%, odds ratio for seropositivity in cases (95% CI) 1.41 (1.00, 1.99). Substantial attenuation of this relationship occurred on adjustment for age, sex, number of siblings, smoking and measures of socio-economic status: odds ratio (95% CI) 1.16 (0.79, 1.70). A similar pattern was seen for seropositivity for all H. pylori strains.
Example Output: Is infection with virulent strains of Helicobacter pylori associated with ischaemic heart disease : evidence from a population-based case-control study of myocardial infarction?

Example Input: This analysis examines whether or not younger caregivers, parents of children with developmental disabilities, differed from controls in terms of cytomegalovirus (CMV) seropositivity and CMV-specific antibody titre. Secondly, it examined whether any particular socio-demographics, health behaviours, or psychological/caregiving variables were associated with a higher CMV antibody titre among caregivers.', 'Young caregivers and age- and sex-matched controls were compared with respect to their reported health behaviour and psychosocial status as well as latent virus control.', 'One hundred and seventeen parents of children with developmental disabilities and 52 control parents completed standard measures of health behaviours, socio-demographics, perceived stress, depression and anxiety, caregiver burden, child problem behaviours. They also provided a blood sample assayed for the presence of CMV-specific antibody.', 'Caregivers were no more likely to be CMV positive than controls and did not have higher antibody titres against CMV. In addition, there was no association between CMV antibody titre in seropositive caregivers and any of the psychological/caregiving variables. However, higher CMV antibody titres were significantly associated with a higher BMI, lower exercise levels, smoking, and lower fruit and vegetable and fat intake among seropositive caregivers.
Example Output:
Are anticytomegalovirus antibody titres associated with caregiving burden in younger caregivers?