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Paracetamol–asthma link “overstated”
THE association between early life exposure to paracetamol and asthma has been overstated, and there is insufficient evidence to support changing guidelines on the use of the drug, according to an Australian systematic review published in the Archives of Disease in Childhood. The authors independently reviewed 11 cohort studies finding that overall the evidence suggested an association between paracetamol exposure during infancy and the increased risk of asthma in childhood. However, when they adjusted for respiratory tract infections during infancy the association attenuated, “supporting the concept that these associations are, at least in part, due to confounding by indication”. They also found any paracetamol use during the first trimester of pregnancy was associated with an increased risk of childhood asthma but there was marked between-study heterogeneity and only one study adjusted for maternal respiratory tract infections. The authors wrote that it was “unlikely that paracetamol is a clinically important risk factor for asthma”. As respiratory tract infections confounded the association between paracetamol and asthma, it was “essential that this be accounted for in future observational studies”. The authors suggested that future research “should also assess the effect of paracetamol exposure on lung function outcomes given that paracetamol is proposed to induce oxidative stress on the airway”.
No evidence on vitamin D screening
A SYSTEMATIC review to examine the benefits and harms of screening for vitamin D deficiency in asymptomatic adults has found no direct evidence that screening affects clinical outcomes compared with no screening. The review, published in Annals of Internal Medicine, was conducted on behalf of the US Preventive Services Task Force because vitamin D deficiency has been associated with adverse outcomes. The review authors found none of the studies evaluated clinical outcomes or harms in people screened versus not screened for vitamin D deficiency. The review did find that in people with low vitamin D levels, treatment was associated with a decreased risk of death, but this effect was not present when three trials of older institutionalised women were excluded from the analysis. Vitamin D treatment was associated with possible decreased risk for having at least one fall and a reduction in falls per person but not in fractures. The authors recommended a trial of screening for vitamin D in a diverse population as an “ideal way to evaluate benefits and harms”. “Future research is needed to reduce assay variability; determine appropriate thresholds for vitamin D deficiency; and clarify effects of screening, subsequent treatment, and the subpopulations most likely to benefit”, the authors wrote.
Good outcomes for retinoblastoma survivors
A REASSURING US study has found that adult survivors of retinoblastoma demonstrate few cognitive or social attainment deficits several decades after diagnosis and treatment. The research, published in Cancer, included 69 adult survivors (mean age, 33 years; mean years post-diagnosis, 31) who had completed clinical cognitive evaluations and questionnaires assessing adult social attainment. The researchers said that retinoblastoma represented about 6.1% of childhood cancer under the age of 5 years. They found their cohort of survivors performed within normative expectations for most cognitive domains. Survivors diagnosed at or before the age of 1 year performed significantly better on measures of short- and long-term verbal memory, verbal learning and verbal reasoning abilities compared with those diagnosed at more than 1 year old. In multivariable models, restricted to survivors of bilateral retinoblastoma and adjusted for age at diagnosis, whole brain radiation exposure was found to be significantly associated with poorer performance on tasks of short- and long-term verbal memory. The researchers said that their finding of better outcomes for those diagnosed and treated before the age of 1 year suggested “the potential for neural reorganization in very young children after an insult to the visual system”.
Obesity-related cancers on rise
A GLOBAL estimate has found high body mass index (BMI) caused about 481 000 new cancers in adults in 2012, with the highest burden in developed countries. In research published in The Lancet Oncology, population attributable fractions (PAFs) were calculated using relative risks and BMI estimates in adults by age, sex and country. Data from a number of sources, including the WHO’s GLOBOCAN2012 project, were used to estimate the numbers of cancers attributable to high BMI in 184 countries. The authors estimated that 3.6% of all new cancer cases in adults aged over 30 years were associated with high BMI. PAFs were higher in women than in men, and uterine, postmenopausal breast, and colon cancers accounted for 63.6% of all cancers attributable to high BMI. A quarter of the cancer cases could be attributed to the increase in population BMI since 1982, the authors wrote. They said their results emphasised the need for a global effort to abate the increasing number of people with high BMI, and “should inform health policy in terms of targets for prevention programmes”. An accompanying comment highlighted that the number of obesity-related cancers was small compared to the size of the world population, and that global health resources targeted at obesity needed to be balanced against those for other important causes of cancer, “particularly infections and tobacco use, which are each associated with much larger proportions of cases”.
ART timing vital in HIV patients
STARTING antiretroviral therapy (ART) more than 12 months after the estimated date of seroconversion (EDS) in HIV patients diminishes the chance of achieving a normal CD4+ T cell count, a US study has found. The research, published in JAMA Internal Medicine, was based on immunologic health outcomes of 1119 participants in an observational study with documented EDS who had achieved virologic suppression with ART when evaluated. CD4+ T cell count normalisation of 900 cells/μL or higher was achieved in 38.4% of patients who initiated ART within 12 months of EDS, compared with 28.3% of those who initiated ART more than 12 months after EDS, the authors wrote. Participants with CD4+ counts of 500 cells/μL or higher at study entry or ART initiation had significantly increased CD4+ normalisation rates compared with other participants. However, even among participants with a CD4+ count of 500 cells/μL or higher at both study entry and before ART, the odds of CD4+ normalisation were 80% lower in those who initiated ART more than 12 months after EDS, the authors wrote. They found that initiation of ART within 12 months was also linked to a significantly lower risk of AIDS, reduced T cell activation and increased responsiveness to hepatitis B vaccine. The authors wrote that the results showed that “achieving CD4+ normalization is an imminently feasible therapeutic goal, provided ART is started within 12 months of the EDS at higher CD4+ counts”. They also highlighted the importance of public health strategies that included frequent HIV testing in those at risk and prompt initiation of ART after diagnosis. An accompanying commentary said the study was a reminder that “the goal of HIV therapy should be full restoration of immune function and not just suppression of viral replication”.
“Virtual” volunteers needed for Ebola
THE Twice the Doctor Foundation, an organisation established by a group of Australian doctors whose philosophy is to take some responsibility for all the world’s patients not just their own, will launch D-Day for Ebola on 8 December. Administered by UNICEF Australia, the aim of D-Day for Ebola is to encourage doctors to “virtually volunteer” by donating a day’s pay to the Ebola disaster relief program. In a media release, Twice the Doctor Foundation director, Dr Robert Baume, said that at the group’s inaugural fundraising event earlier this year, signed up enough doctors to raise $200 000. He said D-Day in December would allow all doctors the opportunity to contribute to the Ebola crisis “without ever coming into danger”. “This is a way to ‘virtually’ volunteer to make a real difference and one day of pay for an Australian doctor goes a long way in Africa”, Dr Baume said. Further information is available at twicethedoctor.org.au/projects/ebola-project/