When applying the algorithm to vertebral fracture assessment (VFA) images taken in older women during routine bone density testing, often as part of treatment plans for osteoporosis, the patient’s presence and extent of abdominal aortic calcification (AAC) was assessed.

The algorithm shortens the timeframe to screen for AAC significantly, taking less than a minute to predict AAC scores for thousands of images, compared with the five to six minutes it would take for an experienced reader to obtain the AAC score from one image.

During her research, ECU research fellow Dr Cassandra Smith found that 58% of older individuals screened during routine bone density testing presented with moderate to high levels of AAC, with one in four walking through the door unaware that they had high AAC, placing them at the highest risk of heart attack and stroke.

“Women are recognised as being under screened and under-treated for cardiovascular disease. This study shows that we can use widely available, low radiation bone density machines to identify women at high risk of cardiovascular disease, which would allow them to seek treatment.

“People who have AAC don’t present any symptoms, and without doing specific screening for AAC, this prognosis would often go unnoticed. By applying this algorithm during bone density scans, women have a much better chance of a diagnosis,” Dr Smith said.

Using the same algorithm, ECU senior research fellow Dr Marc Sim found that these patients with moderate to high AAC scores also had a greater chance of fall-associated hospitalisation and fractures, compared with those with low AAC scores.

“The higher the calcification in your arteries, the higher the risk of falls and fracture,” Dr Sim said.

“When we look at traditional falls and fracture risk factors, things like have you fallen in the past year and bone mineral density are generally very good indicators of how likely someone is to fall and fracture. Some medications are also associated with higher falls risks. Rarely do we consider vascular health when considering falls and fractures.

“Our analysis uncovered that AAC was a very strong contributor to falls risks and was actually more significant than other factors that are clinically identified as falls risk factors.”

Dr Sim said that the new machine algorithm, when applied to bone density scans, could give clinicians more information around the vascular health of patients, which is an under-recognised risk factor for falls and fractures.

While the chemicals, called phthalates, are in widespread use globally, the Middle East, South Asia, East Asia, and the Pacific bore a much larger share of the death toll than others — about three-fourths of the total.

For decades, experts have connected health problems to exposure to certain phthalates found in cosmetics, detergents, solvents, plastic pipes, bug repellants, and other products. When these chemicals break down into microscopic particles and are ingested, studies have linked them to an increased risk of conditions ranging from obesity and diabetes to fertility issues and cancer.

Led by researchers at NYU Langone Health, the current study focused on a kind of phthalate called di-2-ethylhexyl phthalate (DEHP), which is used to make food containers, medical equipment, and other plastic softer and more flexible. Exposure has been shown in other studies to prompt an overactive immune response (inflammation) in the heart’s arteries, which, over time, is associated with increased risk of heart attack or stroke. In their new analysis, the authors estimated that DEHP exposure contributed to 356,238 deaths, or more than 13% of all global mortality from heart disease in 2018 among men and women ages 55 through 64.

“By highlighting the connection between phthalates and a leading cause of death across the world, our findings add to the vast body of evidence that these chemicals present a tremendous danger to human health,” said study lead author Sara Hyman, BS, an associate research scientist at NYU Grossman School of Medicine.

According to the authors, the resulting economic burden from the deaths identified in their study was estimated to be around $510 billion and may have reached as high as $3.74 trillion.

In a past study from 2021, the research team tied phthalates to more than 50,000 premature deaths each year, mostly from heart disease, among older Americans. Their latest investigation is believed to be the first global estimate to date of cardiovascular mortality — or indeed any health outcome — resulting from exposure to the chemicals, says Hyman, who is also a graduate student at NYU School of Public Global Health.

A report on the findings is publishing online April 29 in the journal Lancet eBiomedicine.

For the research, the team used health and environmental data from dozens of population surveys to estimate DEHP exposure across 200 countries and territories. The information included urine samples containing chemical breakdown products left by the plastic additive. Mortality data was obtained from the Institute for Health Metrics and Evaluation, a research group in the US that collects medical information worldwide to identify trends in public health.

Among the key findings, the study showed that losses in the combined region of East Asia and the Middle East and the combined region of East Asia and the Pacific accounted, respectively, for about 42% and 32% of the mortality from heart disease linked to DEHP. Specifically, India had the highest death count at 103,587 deaths, followed by China and Indonesia. The larger heart death risks in these populations held true even after the researchers adjusted their statistical analysis to take into account population size within the studied age group.

A possible explanation, the authors say, is that these countries face higher rates of exposure to the chemicals, possibly because they are undergoing a boom in plastic production but with fewer manufacturing restrictions than other regions.

“There is a clear disparity in which parts of the world bear the brunt of heightened heart risks from phthalates,” said study senior author Leonardo Trasande, MD, MPP. “Our results underscore the urgent need for global regulations to reduce exposure to these toxins, especially in areas most affected by rapid industrialization and plastic consumption,” added Trasande, the Jim G. Hendrick, MD, Professor of Pediatrics at NYU Grossman School of Medicine.

Trasande, who is also a professor in the Department of Population Health, cautions that the analysis was not designed to establish that DEHP directly or alone caused heart disease and that higher death risks did not take into account other types of phthalates. Nor did it include mortality among those in other age groups. As a result, the overall death toll from heart disease connected to these chemicals is likely much higher, he says.

Trasande says that the researchers next plan to track how reductions in phthalate exposure may, over time, affect global mortality rates, as well as to expand the study to other health concerns posed by the chemicals, such as preterm birth. Trasande also serves as director of NYU Grossman School of Medicine’s Division of Environmental Pediatrics and the Center for the Investigation of Environmental Hazards.

Funding for the study was provided by National Institutes of Health grant P2CES033423. Further study funding was provided by Beyond Petrochemicals.

Trasande has received support for travel or meetings from the Endocrine Society, World Health Organization, the United Nations Environment Programme, Japan’s Environment and Health Ministries, and the American Academy of Pediatrics. He has also received royalties and licenses from Houghton Mifflin Harcourt, Audible, Paidós, and Kobunsha, and has served in leadership or fiduciary roles at Beautycounter, Ahimsa, Grassroots Environmental Education, and Footprint. None of these activities were related to the current study. The terms and conditions of all of these relationships are being managed by NYU Langone Health.

In addition to Hyman and Trasande, other NYU Langone researchers involved in the study are Jonathan Acevedo, MPH, and Chiara Gianarelli, MD, PhD.

The team, from the University of Leeds and the UK Centre for Ecology and Hydrology has provided the first ever analysis of how patterns of recent rainfall can interact with dry or moist land conditions to influence the risk of extreme humid heat in the global tropics and subtropics.

The study, which is published today in the journal Nature Communications, offers new insight which could lead to the development of early warning systems for vulnerable communities in those regions.

Climate change means humid heatwaves are a growing risk to human and animal health, especially in tropical regions. While there is established research into dry heatwaves, there is little understanding of the meteorological drivers of extreme humid heat.

Humid heat is related to heat stress, occurring when environmental conditions overwhelm the body’s ability to cool itself. Severe heat stress leads to an increase in the core body temperature of 3°C or more and can cause confusion, seizures, and loss of consciousness. If not treated promptly, severe heat stress can lead to muscle damage, major organ failure, and death.

Humid heatwaves are particularly concerning for humans because a wet-bulb temperature (a measure of temperature that accounts for how much cooling can occur through evaporation under ideal conditions) of 35°C means they are unable to shed heat effectively through sweating. Several subtropical coastal locations have already experienced this 35°C threshold.

Lead author of the study Dr Lawrence Jackson, a Research Fellow in the School of Earth and Environment, said: “With climate change driving more frequent and intense humid heat events, particularly in tropical and subtropical regions, the risks to vulnerable populations and outdoor workers are increasing.

“The new understanding provided by our research highlights the potential for improved humid heat early warning systems, using near real-time satellite observations for soil moisture and rainfall.”

The team studied humid heatwaves across the tropics and subtropics using weather and climate data from 2001 to 2022.

The researchers identified heatwave events and looked at how they were influenced by recent rainfall, using satellite observations to distinguish between wetter and drier days. They then calculated how likely a heatwave was to occur after these different rainfall conditions.

Humid heatwaves are widespread across the global tropics and subtropics. They occur in monsoon regions such as West Africa, India, East China, and north Australia, in humid regions such as the Amazon, southeast US, and the Congo basin, and in hot coastal regions in the Middle East.

The new study reveals that recent rainfall patterns play a critical role in triggering humid heatwaves in tropical and subtropical regions, with the results showing that the risk of humid heatwaves depends on whether the surface environment is drier or wetter.

In drier regions, humid heatwaves are more likely during or just after periods of enhanced rainfall. In wetter regions, humid heatwaves tend to follow at least two days of suppressed rainfall.

This difference arises because rainfall increases moisture in soils making conditions more humid. By contrast, less rainfall and fewer clouds allow the land to warm, thereby increasing temperatures.

Cathryn Birch, Professor in Meteorology and Climate in the School of Earth and Environment, led the study. She explained: “The outlook for tropical humid heat is really concerning. Humans avoid overheating by sweating. Evaporation of the sweat cools your body, allowing you to maintain a safe body temperature. Humidity makes this less effective.

“Humid heatwaves can be lethal at air temperatures that for dry heat would be relatively safe. The tropics are naturally humid and even an apparently small increase in global temperatures leads to large increases in dangerous humid heat extremes. We not only need to urgently cut greenhouse gas emissions but also need improved early warning systems for humid heat.

Co-author John Marsham, a Professor of Atmospheric Science in the School of Earth and Environment, added: “Our results focus on the daily timescale for these heatwaves. An obvious next step would be to extend our analysis to hourly time scales which might allow us to work towards near real-time predictions with all the benefits that would bring to vulnerable communities.”