Pesticide exposure appears to be linked to lower sperm concentrations in men around the world, a new large-scale evidence review has concluded. A review of 25 studies spanning nearly 50 years found consistent links between lower sperm concentrations and two widely used classes of insecticides, organophosphates and N-methyl carbamates, researchers said. “This review is the most comprehensive review to date,” said senior researcher Melissa Perry, dean of the George Mason University College of Public Health in Fairfax, Va. “The evidence available has reached a point that we must take regulatory action to reduce insecticide exposure.” Perry’s team systematically reviewed 25 human studies of occupational and environmental insecticide exposure, conducted over the past half-century. The findings, published Nov. 15 in the journal Environmental Health Perspectives, revealed evidence of robust associations between insecticide exposure and lower sperm concentration. “Understanding how insecticides affect sperm concentration in humans is critical given their ubiquity in the environment and documented reproductive hazards,” said co-researcher Lauren Ellis, a doctoral student at Northeastern University. “Insecticides are a concern for public health and all men, who are exposed primarily through the consumption of contaminated food and water.” More information The Mayo Clinic has more on healthy sperm. SOURCE: George Mason University, news release, Nov. 15, 2023  read on >

Controlled forest burns can prevent the sort of high-intensity wildfires that have plagued the Western U.S. and Canada as a result of climate change, a new study argues. A low-intensity fire in the mixed conifer forests of California provides an estimated 60% reduction in the risk of a catastrophic wildfire, and that effect lasts at least six years, researchers report in the journal Science Advances. Controlled burns also could provide a smaller but still significant reduction in risk in oak-dominated forests, researchers added. “I’m hopeful that policymakers will rely on this work as motivation and support for the scale-up of beneficial fire as a key strategy in preventing wildfire catastrophes,” co-author Michael Wara, director of the Climate and Energy Policy Program at the Stanford Woods Institute for the Environment, said in a Stanford news release. “Beneficial fire is not without its own risks – but what our study shows is just how large and long-lasting the benefits are of this crucial risk reduction strategy,” Wara said. The U.S. Forest Service has proposed treating about 50 million acres of forest through a mixture of “fuel treatment strategies,” which can include burns as well as thinning, pruning and logging to reduce the amount of combustible vegetation, researchers noted. For the study, researchers reviewed two decades of satellite monitoring of wildfires covering nearly 25 million acres of California…  read on >  read on >

The party drug and anesthetic ketamine is starting to show promise in trials as a treatment for depression. But new research also suggests that hundreds of U.S. clinics may be misleading consumers, hawking off-label and unapproved ketamine to treat a variety of mental health and pain conditions. “These are expensive treatments for which patients generally must pay out of pocket and the evidence base is often not robust for many of the advertised uses,” said co-lead study author Michael DiStefano, an assistant professor in the department of clinical pharmacy at Colorado University’s Skaggs School of Pharmacy. “It is important that people considering these treatments are provided with an accurate and balanced statement of the possible risks and benefits.” In the study published Nov. 7 in the journal JAMA Network Open, the researchers noted that ketamine delivered intravenously is not yet approved by the U.S. Food and Drug Administration to treat any mental health condition, but it is sometimes used off-label for such use. Ketamine in pill form isn’t approved to treat anything, either, but is often advertised to produce a hallucinogenic experience at home, the researchers said. Using six national ketamine databases, DiStefano’s team tracked how ketamine is being sold. They identified online direct-to-consumer ketamine advertisers who had websites plus at least one clinic in Maryland. The researchers found 17 advertisers operating across 26 locations…  read on >  read on >

The gap in life expectancy between American men and women is now the biggest it has been since the mid-1990s — almost six years. The pandemic and opioid overdoses are key factors in the gender difference in longevity, said researchers from the University of California, San Francisco (UCSF) and Harvard University T.H. Chan School of Public Health. “There’s been a lot of research into the decline in life expectancy in recent years, but no one has systematically analyzed why the gap between men and women has been widening since 2010,” said first study author Dr. Brandon Yan, a resident in internal medicine at UCSF. In 2021, the gender gap in life expectancy rose to 5.8 years, its largest since 1996, he and his colleagues report. In 2010, the gap was its smallest in recent history, 4.8 years. Life expectancy in the United States was 76.1 years in 2021. That’s down from 78.8 years in 2019 and 77 years in 2020. Researchers cited the pandemic as the biggest factor in the widening gender gap; it took a heavier toll on men. Unintentional injuries and poisonings (mostly drug overdoses), accidents and suicide were other contributors. Another factor in Americans’ shrinking lifespan: so-called “deaths of despair.” That’s a nod to the rise in deaths owing to such causes as suicide, drug use disorders and alcoholic liver disease. These…  read on >  read on >