On-the-job heat stress a threat to more workers
As high temperatures become more common around the world, workers in the Americas are among those experiencing steep increases in related illnesses, a new report says.
About 231 million workers were exposed to heat waves in 2020, a 66% increase in two decades, according to the International Labor Organization report, which tallied 4,200 related deaths that year.
While heat waves take their toll on health, 80% of extreme heat-related occupational injuries happening at other times of the year.
Overall, workers in Africa, the Arab states, Asia and the Pacific region are most often exposed to excessive heat. However, the Americas, Europe and Central Asia are experiencing the biggest increases in workplace injuries from heat stress. The findings suggest regions most affected by rising temperatures may be the ones that are historically not acclimated to them, the researchers said.
In the Americas alone — which includes the U.S., Canada, Mexico and Central and South America — heat-related occupational injuries have increased 33.3% since 2000.
Heat-related injuries include heat stroke, cramps or rash, and on the more serious side, cardiovascular, respiratory and kidney damage. More than 26.2 million people globally were living with chronic kidney disease from heat stress in 2020, researchers reported.
As human-caused climate change continues to raise global temperatures, more prevention, education, monitoring and mitigation of health stress is needed for workers, the report recommended.
Chemical exposure can disturb gut bacteria
Exposure to a common environmental chemical early in life may disrupt healthy bacteria in the gut, contributing to metabolic diseases later in life, a new study says.
Published Aug. 14 in Environmental Health Perspectives, the study focused on 2,3,7,8-tetrachlorodibenzofuran, a pollutant that comes from waste incineration, metal production, paper bleaching and other sources. Also known as TCDF, the chemical is widespread and long-lasting in the environment.
Researchers studied young mice to model the effects of TCDF on humans, finding that exposure to the chemical interfered with the animals’ gut microbiomes. The change led to higher body weight and glucose intolerance as they aged.
When another group of mice that had not been exposed to the chemical received intestinal microbiome transplants from those that had, they developed metabolic disorders as well.
A number of gut bacteria were particularly decreased by exposure to TCDF, including Akkermansia muciniphila, which is also found in the human gut.
The findings suggest that people exposed to TCDF during early childhood may be at higher risk for metabolic disorders in adulthood, such as obesity and Type 2 diabetes, the researchers said.
Human exposure to TCDF commonly comes through eating high-fat food, such as meat, dairy and some fish. But the chemical can also be inhaled, absorbed through touch and spread through breast milk.
Food industry determines which substances are safe, researchers say
The U.S. government’s reliance on the food industry to determine which ingredients are considered safe has allowed new substances to enter the nation’s food supply without oversight, according to a new article from public health researchers.
While the U.S. Food and Drug Administration assesses the safety of food additives before they reach the market, it allows the food industry to determine which substances are “generally recognized as safe,” or GRAS. That ability has allowed food manufacturers to add thousands of substances to food on which safety data is unknown, said the article, which was published in the American Journal of Public Health.
An official FDA designation, GRAS originally covered ingredients already included in food, such as spices. But since a 1997 rule change, FDA has allowed food manufacturers to evaluate ingredients and decide what falls under the designation, with no requirement to notify FDA.
The loophole has allowed the food industry to use substances at potentially unsafe levels, such as high caffeine in energy drinks, and to add substances that have questionable safety, such as potassium bromate, a dough-strengthening chemical that has been named as a possible human carcinogen by the International Agency for Research on Cancer.
While FDA rarely reviews or revokes use of GRAS substances already on the market, the agency said in March that it was reviewing 21 chemicals found in foods, including potassium bromate, bisphenol A, lead and per- and polyfluoroalkyl substances.
Greenhouse gases from food a growing concern
Food production accounts for a third of all human-created greenhouse gas emissions around the world, but reductions have stalled, a new study in the Proceedings of the National Academy of Sciences says.
Researchers examined data from 180 countries, finding that the amount of emissions per unit of protein fell by almost two-thirds worldwide across the past six decades. In the past 10 years, however, emission levels have stagnated, despite work by global leaders to stem the causes of climate change, including greenhouse gases emissions.
In some countries, thanks to growth in livestock production and crop changes, agricultural-related emissions have actually increased, the study found. Livestock production, which releases both carbon dioxide and methane, accounts for about two-thirds of food-related emissions.
While the issue is concerning now, it may be even more so in the next 20 years: Due to growing populations and greater wealth, global food production is expected to increase by as much as 56% by 2050. At that rate of growth, targets to limit global temperature increases would be critically endangered, the study said.
Researchers said measures such as dietary changes, enhancing fertilizer efficiency and providing better nutrition to cows and other ruminant animals can reduce emissions, as well as minimizing land use changes and maximizing international trade.
An Aug. 13 study in Nature Climate Change found that food-related greenhouse gas emissions could fall by 17% if people adopted more plant-based diets.
Other recent public health news of note includes:
• Only 10% of women with private insurance who had a mental health diagnosis of anxiety or depression during pregnancy or a year postpartum received therapy, found a study in JAMA Network Open.
• Wildfires driven by climate change are harming decade-long improvements in air quality in the U.S., a study in Environmental Science & Technology finds.
• A new study in Health Affairs reports that Medicaid vision coverage for adults varies widely by state, harming access to care. About 12% of Medicaid enrollees live in states without coverage for routine adult eye exam and 27% are in states without coverage for eyeglasses.
• Rising global temperatures from climate change could raise mercury levels in soil, allowing more of the substance to pass into the human food chain, reports new science in Environmental Science & Technology.
The Watch is written by Michele Late, who has more than two decades of experience as a public health journalist.