University of Murcia

A study published in Nature in which researchers from the University of Valencia have participated has identified a neuron migration route that begins in the foetus around mid-gestation and continues until between two and three years of age. The route extends from the lateral ventricle, where these cells are born, to the entorhinal cortex, an area related to the regions where memory and learning are consolidated. There, neurons await signals that induce them to mature, providing plasticity to the brain after birth.

Mercury concentrations in tuna have remained stable between 1971 and 2022, even though emissions of this metal from human activities have decreased over the same period, a study says. 'Aggressive' emission reduction targets are needed to achieve measurable declines in concentrations of this pollutant, which is toxic for human health, the authors write in the journal Environmental Science & Technology Letters. The Minimata Convention on Mercury, a global treaty that entered into force in 2017, bans new mercury mines and includes provision to reduce mercury use, but mercury has already accumulated in the ocean 'for centuries', the article says.

Heavy metals - including arsenic, cadmium and mercury - may adversely affect the ovaries of women approaching menopause, a study claims. Those with high levels of metals in their urine had lower levels of anti-Müllerian hormone, indicating diminished ovarian reserve - fewer oocytes in the ovaries compared to other women of that age. The authors, whose study is published in The Journal of Clinical Endocrinology & Metabolism, used urine data from more than 500 women in the US up to 10 years before their last menstrual period.

Drinking less than 25 grams of alcohol a day (2.5 standard drinking units, the equivalent of two and a half pints) does not reduce mortality, according to an analysis that aggregates data from 107 previous studies and 4.8 million people. Some studies claim that people who drink alcohol in low doses live longer and are less likely to die of cardiovascular disease than those who abstain completely. This meta-analysis published in JAMA Network Open, which brings together studies published between 1980 and 2022 in several countries, found no such protective effect. It did find a significant increase in the risk of mortality at 25 g per day for women and 45 g per day for men. In Spain, the Ministry of Health sets the limits for low-risk consumption at 10 g of alcohol per day for women and 20 g for men.

Using genetic data from more than 340,000 participants of European descent, research has identified five genetic variants that make people more susceptible to myopia in combination with intensive schooling, especially university studies. The results are published in PLOS Genetics.

A study published in the BMJ looks at the risk of thromboembolic events associated with different covid-19 vaccines, both adenovirus- and mRNA-based. Its results are based on data collected from more than 10 million adults in France, Germany, the Netherlands, Spain, the UK and the US who received at least one dose of a covid-19 vaccine from December 2020 to mid-2021.

A survey conducted by the COSMO-Spain team to find out the reasons why some people have not yet been vaccinated showed that most of them fear that vaccines are unsafe and their side effects. These results highlight the importance of rigorous communication of drugs that are considered safe and effective by all studies and agencies.