Tag Archive | epidemiology

Contact With Natural Spaces Improves the Health of the Population

park in the city 2


In this recent post by the HealthISglobal blog, Margarita Triguero, a PhD student at CREAL (now part of ISGLobal), gives us an overview about some recent studies showing the effects of natural spaces – mostly green spaces, both big and small – on health. As she says, blue spaces, such as lakes, rivers, or the sea, have been much less studied so far, but that’s about to change with a new international project called “BlueHealth Project“, which is led from the UK and in which the CREAL/ISGlobal researchers are involved.

Looking forward to hear more about this new project, which started earlier this year and will run until 2020! For the time being, you can read Margarita’s post here!


Bad times, slimmer children?

On January 21, Judit Vall Castelló from the Centre for Research in Health and Economics (Pompeu Fabra University) gave a conference at the PRBB invited by the CREAL. She talked about her last study on the effect of business cycle conditions on children’s weight.

She explained that the majority of the research connecting recessions with body-weight has so far focused on adults or babies. In adults, most of the literature finds a link between better economy and weight increase, which would suggest that recessions are “good” for adult’s health. But, is it the same for children?


Spain is one of the ten countries of the OECD with a higher prevalence of infant overweight – about 25% of children aged 5 to 17.  Children’s obesity rates represent an important public policy issue as a number of short-term adverse effects and risks have been associated with obesity in the early stages of life. For example, obese children have a greater risk of being bullied and they are more likely to stay obese into adulthood, therefore having a higher probability of suffering certain chronic diseases later in life.

The relationship between the business cycle conditions and children’s weight is not in the political agenda of Spanish politicians, it’s an unexplored topic on the scientific literature about children, and it has relevant consequences in the short and long-term. These were the main motivations for Vall Castello’s research.

Her team used data from 8 waves (1987-2012) of the Spanish National Health Survey. The pooled sample contained 37,562 observations of children between the ages of 2 and 15 years old.

She explained to an attentive audience how their strategy takes advantage of the variation in the unemployment rate across regions and survey years to look for potential effects. They used the regional unemployment rate as a proxy for the business cycle phase at the local level.

The researchers found that an increase in the unemployment rate is associated with lower obesity incidence, especially for children under 6 years old and over 12 years old – similarly to what was known in adults. A decrease in obesity is actually good news, but what happens to the other extreme of the population, the ones that were already underweight when the economy was good?

They found that negative economic conditions increased the prevalence of infant underweight, particularly for those under 6. So, an increase in the unemployment rate shifts the entire weight distribution to the left, decreasing the probability of suffering obesity and overweight but at the same time increasing the probability of being underweight for children under 6 and children over 12.

fotookbad times

There is a positive correlation between unemployement and the prevalence of infant underweight

Vall Castello was also interested in the possible channels through which the economy could be impacting infant underweight and obesity, such as changes in the nutritional composition of the children’s diet or in the frequency of exercise.

Their results suggest that an increase in the local unemployment rate may be linked to a decrease in the probability of following a Mediterranean Diet, which is considered as one of the healthiest dietary options. More worryingly, this negative correlation was most significant for children under 6 years old.

Since compulsory education starts at age 6 in Spain – and, for most children, it includes lunch at school – this research seems to point out just how important it is to ensure that all children, regardless of their parents’ economic situation, have at least one balanced meal a day, and the key role schools play in this.

bad times


A report by Mari Carmen Cebrián 

Europeans are becoming more aware of the city air around them

Guest post written by Tom Cole-Hunter, researcher at the CREAL. Photos by Raül Torán.

per post creal icfo4

In the months of September and October, the Centre for Research in Environmental Epidemiology (CREAL, an ISGlobal centre) collaborated with the Institute of Photonic Sciences (ICFO) as partners in the iSPEX-EU project. The essence of this project is to capitalize on large-scale, citizen contributions to science (‘citizen science’) such as observations of their environment with simple tools that compliment their existing way-of-life.

CREAL, identified by ICFO as now prominent in local citizen science activities due to leading roles in projects such as CITI-SENSE, was approached to assist in the recruitment of citizens. To participate in the project, citizens had to download an application and clip-on an ‘add-on’ to their smartphone to make an objective observation of the atmospheric air. The add-on, pictured above attached to a smartphone, works on the principle that aerosols (tiny liquid or solid particles, such as sea salt, soot and sand) interact with light in that they scatter and absorb it changing its intensity and polarization – this way the add-on, technically a spectropolarimeter, measures the amount, the size and the type of aerosols.

Volunteers using the device to measure aerosols

Volunteers using the device to measure aerosols

Although the idea is simple and the method fun, several challenges were presented for the recruitment of participants in iSPEX-EU. The first main challenge was that the associated smartphone application and add-on were only compatible with iPhone 4/4s/5/5s. The second was that clear weather and indirect sun were needed to make a measurement. Other challenges included limited time for being on the street recruiting. All of these challenges meant that we were not able to recruit as many participants as we had hoped. A lesson learned is that more inter-compatible products should be considered and developed if possible to allow the maximum participation of citizens.

Air quality and citizenship empowerment

It is imperative to involve the public in these types of campaigns as air quality has an impact on us all; it affects our health, our air transport system and the climate. Knowing the distribution of aerosol/particle sizes and types helps to inform regulation of air quality and policy decision-making. Some particles are small enough to bypass our natural filtration system in the nose and throat and reach deep into the lungs. The smallest of them may pass through the lungs through the circulatory and even nervous system and be found in organs such as the heart and even the brain causing serious health effects. Larger particles emitted with industrial processes like generating electricity with coal-fired power plants play an important, detrimental role in climate change. Additionally, natural disasters such as forest fires and volcanic eruptions can dramatically reduce visibility and may even stop air traffic due to the risk of crashing posed by engines being clogged and malfunctioning.

While natural disasters mostly cannot be prevented, acting to reduce traffic and industrial emissions can. CREAL’s involvement in the CITI-SENSE project is to help empower citizens with environmental health information so as to identify and move to improve air quality issues through awareness, education and services enabling change. One such service is the CityAir smartphone application, available for both Android and iOS, which enables citizens to make observations of the environmental quality of the places where they are based on their perceptions. These perceptions are anonymised, collected and shown on a public platform to identify areas of concern. This information can then be used to make a case for improving local, if not global, conditions.

CITI-SENSE is a four-year Collaborative Project partly funded by the EU FP7-ENV-2012 under grant agreement No 308524, started in October 2012. iSPEX-EU is part of LIGHT2015, a project funded through the European Union’s Horizon 2020 research and innovation programme under grant agreement No 644964.


“Cancer prevention requires the vision, courage, and political leadership to make long term decisions”

6, Christopher Wild (IARC) 2 retalladaChristopher Wild has been the Director of the International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization (WHO), since 2009. Married to a neuroscientist and father of three, this epidemiologist and Man United fan came to the PRBB in March to give the 3rd Global Health session co-organised by ISGlobal, CRESIB, and CREAL.

How has the burden of cancer changed over recent years?

The incidence of cancer globally has increased: there were 14 million new cases in 2012 and it is expected we will reach 24 million new cases by 2035. Also, about 70% of the world’s cancer deaths occur in low- and middle-income countries. This is due to the rise in population sizes and average life expectancy in general, particularly in these countries, but also because they are shifting towards ‘industrialised’ lifestyle habits such as increased smoking, alcohol consumption, unhealthy diets, obesity and lack of physical exercise, which we know are linked to cancer.

Who should ensure decisive action is taken against these known risks?

First the researchers need to provide reliable scientific evidence on which to base decisions. Once the scientific evidence is available it is down to national authorities to make informed regulatory decisions. However, scientists can probably explain the interpretation of their findings more clearly when presenting them to decision-makers.

Why is prevention so hard?

There are different elements involved. First, intervention may require co-ordination across different parts of government and society. Second, there are often infrastructural, economic or cultural barriers. For example, in some developing countries, vaccinating against human papilloma virus to prevent cervical cancer might be interpreted as a signal of sexual promiscuity. This is why I think much more research has to be conducted on the factors which affect the implementation of prevention in routine healthcare settings. This is an often neglected area.

Finally, sometimes the case is not made politically and there is a failure to translate scientific evidence into guidelines. One of IARC’s important jobs is to evaluate prevention strategies, to find out what works. This research must be independent of vested interests, and here the position of the Agency within the UN has a major advantage. It also gives us the opportunity to improve the translation of knowledge into action at the level of individual countries.

Where do we need to invest more in the fight against cancer?

Prevention is central to reducing the rising trend of cancer, and we know that more than 50% of cases could be prevented if what is currently known were to be implemented efficiently; if governments took strong action, such as enforcing anti-tobacco controls, ensuring vaccination against HBV and HPV, promoting healthier lifestyles and improving access to health care including the early detection of breast, cervical, and colorectal cancers. But investment in prevention requires the vision, courage, and political leadership to make decisions and financial commitments that will bear fruit, often many years in the future.

This interview was published in the October 2014 edition of El·lipse, the monthly newspaper of the PRBB

You can read a related post here.

Science at PRBB: Roberto Elosua’s group on cardiovascular epidemiology and genetics

The Cardiovascular epidemiology and genetics research group, led by Roberto Elosua and Jaume Marrugat at the IMIM, tries to identify the incidence of cardiovascular diseases, their determinants and evaluate prevention strategies. In this short video, Dr Elosua explains their research more in detail.

Science at PRBB: Cristina Villanueva (CREAL) and water pollution


The water we use to drink, shower or swim can affect our health. Listen to Cristina Villanueva explaining in this short video what they are studying at the Water pollution research programme of the Centre for Environmental Epidemiology (CREAL). Video produced by the Barcelona Biomedical Research Park (PRBB).

Science at PRBB video: Mark Nieuwenhuijsen’s lab (CREAL) in one minute

How is our health affected by pollution, green spaces, urban design and active transport? This is what Mark Nieuwenhuijsen is studying at the Centre for Research in Environmental Epidemiology (CREAL), located at the Barcelona Biomedical Research Park (PRBB). In this short video the Dutch researcher explains his studies on how outdoor contaminants affect health.

DNA isolation method may affect methylation results

Researchers from the neurovascular research group at the IMIM have recently published a paper showing that, when studying DNA methylation, the protocol used for DNA isolation can affect the results.

In the paper published in the Open Access journal PLoS One, Jaume Roquer and the rest of the authors – all part of the Spanish Stroke Genetics Consortium – used three different commercial kits for DNA extraction for each sample, and then quantified the global DNA methylation (GDM) by a luminometric methylation assay (LUMA). In the 580 samples analysed, they found significant differences in GDM in the same samples between the three DNA isolation methods.

Large epidemiological studies, such as those carried out by the Spanish Stroke Genetics Consortium, are susceptible to accumulate variability by differences in the protocols, sample cohorts, reagent lots, and technologies used. This study demonstrates for the first time that the method of DNA extraction is indeed an important source of variability in LUMA methylation measurements.

The problem of this ‘batch effect’ becomes even more pronounced in collaborative studies, where different cohorts and differences in sample processing may threaten comparability of data and results. That is why the authors – which include Roberto Elosua’s group, also at the IMIM – recommend that methylation studies that apply multiple DNA extraction methods or in cross study comparisons should report the method used, and adjust their methylation results by this variable in order to avoid possible bias, be comparable and reach biologically meaningful conclusions.


Soriano-Tárraga C, Jiménez-Conde J, Giralt-Steinhauer E, Ois A, Rodríguez-Campello A, Cuadrado-Godia E, Fernández-Cadenas I, Montaner J, Lucas G, Elosua R, Roquer J, GeneStroke “The Spanish Stroke Genetics Consortium”. DNA Isolation Method Is a Source of Global DNA Methylation Variability Measured with LUMA. Experimental Analysis and a Systematic Review. PLoS One. 2013;8(4):e60750

Environmental exposures and child health – a new European study

The official kick-off of the HELIX project (The Human Early-LIfe Exposome) will be taking place on March 11-13 at the PRBB, with public conferences in the Auditorium on the first day.

Coordinated by Martine Vrijheid from CREAL, HELIX has received €8.6M from the European Commission’s 7th Framework Programme. It aims to build an early life “Exposome”, a collection of all early-life environmental exposures affecting children, and it has 4 years and a half, from January 2013 to July 2017, to do so. HELIX will develop tools to measure the exposome, including the use of smartphones and biological markers.

The project involves 13 partners from eight European countries, including two SME’s and six birth cohort studies from France, Greece, Norway, Spain and the United Kingdom.

How much pollution are you exposed to? Ask your smartphone!


Exposure assessment in epidemiological studies is a tricky issue, because of the difficulty of constantly tracking people’s activity and location, both of which can affect the exposure to pollution. Researchers at CREAL have shown how using smartphone technology can help to reduce this bias in health effects estimates.

Audrey de Nazelle, a postdoc at Mark Nieuwenhuijsen’s lab who has currently started her own group at the Centre for Environmental Policy, Imperial College in London, used the CalFit smartphone technology to track person-level time, geographic location, and physical activity patterns for improved air pollution exposure assessment. CalFit is a ubiquitous sensing technology developed at UC Berkeley. It consists on using a GPS and an accelerometer in a smartphone to record the location and physical activity of the carrier through energy expenditure and activity tracking algorithms. de Nazelle and her colleagues at CREAL distributed CalFit-equipped smartphones to 36 subjects in Barcelona to obtain information on physical activity and geographic location. This information was then linked to space-time air pollution mapping.

The authors of the paper, published in Environmental Pollution, found that information from CalFit could substantially alter exposure estimates. For instance, travel activities – which wouldn’t have been measurable without the use of the mobiles – accounted on average for 6% of people’s time and 24% of their daily inhaled NO(2).

The potential of this technology for epidemiological studies is enormous. As the authors state, the large number of mobile phone users makes this technology a potential unobtrusive means of enhancing epidemiologic exposure data at low cost. In fact, they are now using it in several epidemiological projects they are involved in, such as the ERC-funded BREATHE study, the EC-funded PHENOTYPE, and the HELIX and EXPOsOMICs studies.


You can read a related interview to de Nazelle here.


de Nazelle A, Seto E, Donaire-Gonzalez D, Mendez M, Matamala J, Nieuwenhuijsen MJ, Jerrett M. Improvingestimates of airpollutionexposurethroughubiquitoussensingtechnologies.EnvironPollut. 2013 Feb 13;176C:92-99

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