The WHO has issued a new guideline advising against the use of non-sweetened sweeteners for weight control or to reduce the risk of noncommunicable diseases. The recommendation is based on the findings of a systematic review published in 2022.

A study led by the University of Montpellier (France) and with the participation of CREAF has analysed the causes of the decline in bird populations in Europe. To do so, they have compiled data on 170 bird species in 28 countries, including Spain, over 37 years. The overall decline is 25 %, and the decline in populations in agricultural areas is around 60 %. The main cause in both cases, according to the research, is intensive agriculture, although climate change is also an important factor. The results are published in the journal PNAS.

A journal article published in the BMJ discusses the potential adverse effects associated with GSK and Pfizer's RSV vaccines in the face of a possible increase in preterm births and argues for further study of the risks and benefits of the drug.

Research led by scientists at Harvard Medical School (USA) has isolated small aggregates of amyloid from the brains of post-mortem Alzheimer's patients. The achievement has made it possible to study the structure of these "clumps", which exist outside plaques and are considered highly toxic, and to test their effect on synapses. In addition, the authors have shown that the drug lecanemab, recently approved by the FDA, is able to bind to them and help neutralise their action. The results are published in the journal Neuron.

In a series of three articles and a companion article - collected in Nature Biotechonology - Nature publishes the first draft of the human pangenome reference, which contains highly detailed data from 47 genetically diverse individuals. The first human genome was published more than two decades ago but, being from a single person, it does not represent human diversity, whereas the pangenome refers to the gene pool of our entire species. The ultimate goal of the Human Pangenome Reference Consortium project is to include genetic material from 350 people by 2024. It is hoped that this data will allow more clinically relevant genetic variants to be identified.

A phase 1 clinical trial has tested personalised mRNA vaccines against the most common type of pancreatic cancer with a particularly poor prognosis. The treatment, which is tailored to the characteristics of each patient's tumour, was given to 16 people along with surgery, chemotherapy and other immunotherapy. Half of them showed an immune response to the vaccine, which was associated with a better prognosis. The results are published in the journal Nature.

The time adolescents spend on social media is one of the least influential factors for their mental health, according to a study published in Nature Mental Health. The analysis attempts to untangle the complex web of risk factors and protective factors, using data from more than 12,000 young people in the UK. Among the factors studied, it concludes that bullying, lack of family support and school work dissatisfaction are more influential than time spent on social media. According to the study, life dissatisfaction and lack of family support are the most influential factors for girls and boys, respectively. 

The World Health Organisation (WHO) Emergency Committee met on 4 May to assess whether covid-19 could continue to be considered a health emergency of international concern (PHEIC). The organisation's director general, Tedros Adhanom, has followed its recommendation and ended the emergency declared on 30 January 2020. "It is with great hope that I declare that covid-19 has ended as a global health emergency. However, this does not mean that covid-19 is no longer a threat to global health. Last week, it claimed one life every three minutes, and that's just the deaths we know about," he told a press conference.

Climate change made the late April episode of record temperatures in the Iberian Peninsula, Morocco and Algeria 100 times more likely to occur, with temperatures up to 3.5°C higher than they would have been without the climate crisis. This is one of the conclusions of an attribution study conducted by World Weather Attribution.

A study published in JAMA Network Open has followed 1,340 women with high-risk operable breast cancer. Analysing their lifestyles before, during and after treatment, the researchers conclude that those who followed a healthier pattern - including physical activity, no smoking, high fruit and vegetable intake, and low consumption of meat and sugary drinks - had a 37% lower risk of relapse and a 58% higher chance of survival than those who followed a worse pattern. Although the improvements in absolute risk were much smaller, the authors conclude that "lifestyle interventions may be a safe, inexpensive and feasible adjuvant strategy to delay and prevent recurrence and death from the world's most common cancer".