The new research, to be presented Tuesday at the 2nd CHILDREN with LEUKAEMIA Causes and Prevention of Childhood Leukaemia Conference in London, is the first comprehensive analysis of studies investigating the association between social contact and childhood leukaemia.
“Combining the results from these studies together provided us with more confidence that the protective effect is real. Analysing the evidence in this way gives a more reliable answer to the question and a more precise estimate of the magnitude of the effect,” said the study’s leader, Dr. Patricia Buffler, professor of epidemiology at the School of Public Health of the University of California, Berkeley.
While the analysis does not reveal how intense social contact might ward off childhood leukaemia, it bolsters the theory that children exposed to common infections early in life gain protection from the disease. It is known that environments such as day care centres increase the chance of infections spreading. Some proponents of the theory believe that if the immune system is not challenged early in life and does not develop normally it may mount an inappropriate response to infections encountered later in childhood and that this could provoke the development of leukaemia.
Leukaemia is the most common cancer found in children in the industrialised world, affecting about one in 2,000 children. Incidence of the disease has been on the increase for decades. Acute lymphoblastic leukaemia, or ALL, the type of leukaemia the studies focused on, accounts for more than 80% of cases and most often occurs in children aged between 2 and 5 years. Scientists believe that for most types of childhood leukaemia to develop, there first must be a genetic mutation in the womb, followed by a second trigger during childhood that results in 1% of those children developing the disease. Infection – or the timing of infection - is one of the suspected triggers.
Buffler’s analysis included 14 published studies comprising a total of 6,108 children with leukaemia and 13,704 without the disease. Parents were asked about day care and playgroup attendance, as well as other forms of social interaction with other children. The studies varied in the timing, duration and extent of social contact investigated and in the age groups and types of leukaemia studied. Twelve of the studies found some indication of a protective effect of social interaction with other children, while two found no effect. No study found that social contact increased the risk of childhood leukaemia.
“Our analysis concluded that children who attended day care or play groups had about a 30% lower risk of developing leukaemia than those who did not. Combined results for studies of day care attendance specifically before the age of 1 or 2 showed a similarly reduced risk,” Buffler said.
The protective effect became even stronger when the researchers omitted from the analysis 5 studies in which the selection of healthy children for the comparison group relied on methods not considered optimal. In that analysis, children exposed to social contact were almost 40% less likely to go on to develop leukaemia than their counterparts.
In a separate report released at the conference on Tuesday by CHILDREN with LEUKAEMIA, scientists reviewed the evidence from studies that have investigated a link between infection and childhood leukaemia. They examined not only the idea that early life infections protect against the disease but also whether vaccination plays a role. In addition, they examined two other related areas of research: the role of infection during pregnancy and whether infection might be a factor influencing childhood leukaemia risk in situations where the population mix changes.
The report concluded that the evidence regarding whether infection during pregnancy or in situations of unusual patterns of population mixing influences the risk is inconclusive at present and that further research is necessary.
“On the question of whether infection early in life protects against leukaemia, the best evidence comes from studies of indirect measures of infection - which eliminates many of the problems common in trying to study infections directly - as well as from studies on immune system stimulation and on the genetics of immune responses,” said one of the report’s authors, Dr. Adrienne Morgan, staff scientist at CHILDREN with LEUKAEMIA.
“Putting our review together with the new analysis on social interaction, we can say pretty confidently that childcare, breastfeeding and vaccination are good things. This gives a steer to the biologists looking for what mechanisms might be at play,” she said.
Emma Ross | EurekAlert!
MRI contrast agent locates and distinguishes aggressive from slow-growing breast cancer
25.09.2017 | Case Western Reserve University
Investigators may unlock mystery of how staph cells dodge the body's immune system
22.09.2017 | Cedars-Sinai Medical Center
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
25.09.2017 | Physics and Astronomy
25.09.2017 | Trade Fair News
25.09.2017 | Physics and Astronomy