People who take multivitamins daily do not have a lower risk of mortality than people who do not use these products, according to a meta-analysis published in JAMA Network Open. The study pooled data from more than 390,000 people, followed for about 20 years in three different cohorts in the United States.  

The frequency and magnitude of extreme wildfires appear to have doubled in the last 20 years. Moreover, the six most extreme years for these events have occurred since 2017, according to a paper published in Nature Ecology & Evolution in which the authors used satellite data from 2003 to 2023. 

Ketamine extended-release tablets are effective, safe and well tolerated in patients with depression resistant to other treatments, according to a phase 2 clinical trial. Compared to intranasal or intravenous use of ketamine, these oral tablets are easier to administer and would provide less dissociative intensity, lower risk of abuse and cardiovascular adverse effects, the authors write in Nature Medicine. 

About one in 5,000 people have a genetic variant in the SMIM1 gene that results in a particular type of blood type called Vel negative. An international team of researchers now describes the same variant as being associated with a predisposition to obesity, metabolic disturbances and lower resting energy expenditure. Women studied with the variant weigh, on average, 4.6 kg more, while in men the difference is about 2.4 kg. The results are published in the journal Med, published by the Cell group. 

Management of gestational diabetes should include earlier testing during pregnancy, as well as testing in the postpartum period, according to a series of papers published in The Lancet. Screening is usually done during the second half of pregnancy, but the authors note that diagnosis and treatment is especially beneficial before 14 weeks of pregnancy. 

Carbon stored globally by plants is shorter-lived and more vulnerable to climate change than previously thought, according to a study published in Science. This has implications for nature's role in climate change mitigation, including the potential for carbon removal projects such as mass tree planting. The research reveals that existing climate models underestimate the amount of carbon dioxide (CO₂) that vegetation absorbs globally each year, but overestimate how long that carbon stays there. 

Cancer immunotherapy, and in particular the so-called checkpoint inhibitors, have improved the prognosis of several types of tumours. However, they are not effective in everyone. Two early-stage clinical trials have tested the addition of a type of immunomodulator to this therapy in patients with lung cancer and Hodgkin's lymphoma, with apparent good results. The results are published in the journal Science.  

A family of more than 1,000 members with origins in Colombia has a mutation called "paisa" that leads to the development of Alzheimer's disease. In 2019, an added mutation in the apoE gene called "Christchurch" was described as conferring strong protection to an individual carrying two copies of it. Now, a study has found that 27 family members carry a single copy and that it is also associated with some degree of protection. According to the authors, who publish their findings in the journal NEJM, the discovery could be used to develop new treatments for the disease. 

A study has compared data from 2,100 accidents involving autonomous vehicles and just over 35,000 accidents involving human-driven vehicles between 2016 and 2022, mainly in California (US). Their findings are that autonomous vehicles are safer in many driving situations, but suffer more accidents in situations such as turning times or during dawn and dusk. The results are published in the journal Nature Communications.  

A clinical trial in Finland has compared the effectiveness of nicotine-containing e-cigarettes and varenicline tablets for smoking cessation. The study, which included 458 participants, found no difference between the two strategies at six months. However, after one year, only varenicline was found to be clearly more effective than placebo. The results are published in the journal JAMA Internal Medicine.