Do supervised consumption sites bring increased crime? Study suggests that’s a myth

Analysis of a decade of crime data challenges assumptions that responses to the overdose crisis have a negative impact on neighborhood safety

McGill University

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

Overdose prevention sites and supervised consumption sites in Toronto are not associated with long-term increases in local crime, McGill University researchers have found.

Over 10 years, crime reports remained stable or declined in neighbourhoods where sites opened, the researchers said. Their findings land amid debates across Canada about how harm reduction services intersect with public health and safety.

“Opposition from the public and policymakers has often centred on neighbourhood safety and decline. We wanted to find out whether the data supported those claims,” said Dimitra Panagiotoglou, an associate professor in McGill’s Department of Epidemiology, Biostatistics and Occupational Health, and Canada Research Chair in the Economics of Harm Reduction, Tier 2.

Comparing over a decade of crime data

The study examined nine overdose prevention and supervised consumption sites that opened beginning in 2017. They all closed in 2025 following policy changes and community pressure.

Using Toronto Police Service data from 2014 to 2025, the researchers tracked five major crimes – assault, auto theft, break and enter, robbery and theft over $5,000 – alongside bicycle theft and theft from motor vehicles, within 400 metres of each site.

“These are crimes that influence how safe people feel in their neighbourhoods and the information people often look to when deciding where to move,” said Panagiotoglou.

Once the sites opened, there was a jump in break and enters in some areas. Over time, those reports declined, as did reports of robberies, thefts over $5,000, bicycle thefts and thefts from motor vehicles across all sites. Assaults and auto thefts showed no consistent association.

Why did crime decline?

The finding that crime did not increase mirrors results from other cities, though the decline was less expected and is not fully understood.

Panagiotoglou said police may have stepped up patrols early on, which could help explain why some crime rose briefly before declining. A change in strategy could also play a role. In 2019, Toronto police launched a mental health and addictions initiative

Show editorially warning

 aimed at improving interactions with people in crisis.

It’s unlikely that the results are explained by fewer people reporting crimes, she noted. In 2018, police adopted a more victim-centred definition of “founded” crime, which led to more reports, not fewer.

Call for 'realism and compassion’

Nearly 10 years after Canada recognized the opioid crisis as a public health emergency, the scholars say polarized views on harm reduction are holding back progress.

“We need both realism and compassion,” said Panagiotoglou. “People’s discomfort is understandable, but the crisis reflects deeper systemic issues, such as housing, employment and the toxic drug supply. We need nuanced conversations about what’s working and what isn’t so we can find solutions.”

About the study

“Toronto’s Supervised Consumption Sites and Local Crime” by Dimitra Panagiotoglou, Jihoon Lim and Geoffrey Ingram et al., was published in JAMA Network Open.

---

Journal

JAMA Network Open

DOI

10.1001/jamanetworkopen.2025.45352 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Toronto’s Supervised Consumption Sites and Local Crime

‘Forever chemicals’ may increase liver disease risk in adolescents by as much as 3-fold

A research collaboration co-led by USC and the University of Hawai’i found that higher levels of two common types of PFAS in the blood were linked to an increased risk of early onset of MASLD, formerly known as fatty liver disease.

Keck School of Medicine of USC

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

A new study co-led by the Southern California Superfund Research and Training Program for PFAS Assessment, Remediation and Prevention (ShARP) Center and the University of Hawai‘i has linked certain common “forever chemicals” to a higher risk of liver disease in adolescents. These synthetic compounds, known as per- and polyfluoroalkyl substances (PFAS), may as much as triple the chances that adolescents develop a liver condition called metabolic dysfunction-associated steatotic liver disease (MASLD) — formerly known as fatty liver disease. 

The findings were published in the journal Environmental Research.

MASLD affects about 10% of children and up to 40% of children with obesity. It is a chronic condition that doesn’t always have telltale symptoms, although some patients experience fatigue, discomfort and abdominal pain. The disease increases long-term risk for type 2 diabetes, heart disease, advanced liver injury, cirrhosis and even liver cancer. 

“MASLD can progress silently for years before causing serious health problems,” said Lida Chatzi, MD, PhD, a professor of population and public health sciences and pediatrics and the director of the ShARP Center, a national center funded by the National Institute of Environmental Health Sciences to investigate PFAS health impacts, advance cleanup technologies and support affected communities. “When liver fat starts accumulating in adolescence, it may set the stage for a lifetime of metabolic and liver health challenges. If we reduce PFAS exposure early, we may help prevent liver disease later. That’s a powerful public-health opportunity.”

PFAS are manufactured chemicals used in nonstick cookware, stain- and water-repellent fabrics, food packaging and some cleaning products. They persist in the environment and accumulate in the body over time. More than 99% of people in the U.S. have measurable PFAS in their blood, and at least one PFAS is present in roughly half of U.S. drinking water supplies.

“Adolescents are particularly more vulnerable to the health effects of PFAS as it is a critical period of development and growth,” said the study’s first and corresponding author Shiwen “Sherlock” Li, PhD, an assistant professor of public health sciences at the University of Hawai‘i. “In addition to liver disease, PFAS exposure has been associated with a range of adverse health outcomes, including several types of cancer.”

Linking PFAS, genetics, and lifestyle

The research examined 284 Southern California adolescents and young adults from two USC longitudinal studies. The participants were already at higher metabolic risk because their parents had type 2 diabetes or were overweight. PFAS levels were measured through blood tests, and liver fat was assessed using MRI.

Higher blood levels of two common PFAS — perfluorooctanoic acid (PFOA) and perfluoroheptanoic acid (PFHpA) — were linked to a greater likelihood of MASLD. Adolescents with twice as much PFOA in their blood were nearly three times more likely to have MASLD. The risk was even higher for those with a genetic variant (PNPLA3 GG) known to influence liver fat. In young adults, smoking further amplified PFAS-related liver impacts.

“These findings suggest that PFAS exposures, genetics and lifestyle factors work together to influence who has greater risk of developing MASLD as a function of your life stage,” said Max Aung, PhD, MPH, assistant professor of population and public health sciences at the Keck School of Medicine. “Understanding gene and environment interactions can help advance precision environmental health for MASLD.”

Li noted that this study is the first to examine PFAS and MASLD in children using gold-standard diagnostic criteria, and the first to explore how genetic and lifestyle factors may interact with PFAS exposure. MASLD also became more common as adolescents grew older, adding to evidence that puberty and early adulthood may increase susceptibility to environmental exposures.

The study builds on recent USC research showing that, for adolescents undergoing bariatric surgery to manage obesity, a PFAS known as PFHpA is linked to more severe liver disease, including inflammation and scarring of connective tissue called fibrosis. 

“Taken together, the two studies show that PFAS exposures not only disrupt liver biology but also translate into real liver disease risk in youth,” Chatzi said. “Adolescence seems to be a critical window of susceptibility, suggesting PFAS exposure may matter most when the liver is still developing.”

About this study

Other co-authors are Jiawen Carmen Chen, Jesse Goodrich, Lily Dara, Lucy Golden-Mason, Ana Maretti-Mira, Zhanghua Chen, Frank Gilliland, Brittney Baumert, Sarah Rock, Sandrah Eckel, David Conti and Rob McConnell, all of USC; Elizabeth Costello, who is affiliated with USC and Brown University; Douglas Walker of Emory University; Scott Bartell and Veronica Vieira of UC Irvine; Tanya Alderete of Johns Hopkins University; Michael Goran of Children’s Hospital Los Angeles; and Alan Ducatman of West Virginia University.

The study was funded by the National Institutes of Health [P42ES036506, R01DK59211, 5P01ES022845-03, 5P30ES007048, 5P01ES011627, R01/ES029944, R01ES030691, R01ES030364, R01ES033688, U01HG013288, R01ES035035, R01ES035056, P50MD17344, T32-ES013678, ES035035], the U.S. Environmental Protection Agency [RD83544101] and the Hastings Foundation. 

---

Journal

Environmental Research

DOI

10.1016/j.envres.2025.123320 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Associations between per- and polyfluoroalkyl substances and metabolic dysfunction-associated steatotic liver disease in adolescents and young adults: modifying roles of age, lifestyle factors, and PNPLA3 genotype

Article Publication Date

12-Nov-2025

COI Statement

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr Chatzi and Dr Ducatman have served as an expert consultants for plaintiffs in litigation related to PFAS-contaminated drinking water.

 

The (metabolic) cost of life

A new study in JSTAT shows how to calculate the minimum energy that cells spend to maintain certain metabolic pathways and suppress alternative ones — a “cost” invisible to mechanical physics.

Sissa Medialab

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Black smoker in 2,980 meters of wa­ter on the Mid-At­lantic Ridge. Some hypotheses suggest that deep-sea hydrothermal vents may have provided favorable conditions for the emergence of early life. In these environments, chemical and energy gradients could have supported primitive chemical systems and metabolic-like processes based on compounds released by hydrothermal activity.

Original image source:

https://commons.wikimedia.org/wiki/File:MARUM-HTQ-01-HiRes.jpg

 

view more 

Credit: MARUM − Zentrum für Marine Umweltwissenschaften, Universität Bremen

There are “costs of life” that mechanical physics cannot calculate. A clear example is the energy required to keep specific biochemical processes active — such as those that make up photosynthesis, although the examples are countless — while preventing alternative processes from occurring. In mechanics, no displacement implies zero work, and, put simply, there is no energetic cost for keeping things from happening. Yet careful stochastic thermodynamic calculations show that these costs do exist — and they are often quite significant.

A new paper published in the Journal of Statistical Mechanics: Theory and Experiment (JSTAT) proposes a way to calculate these costs from a thermodynamic perspective and thus to offer a new tool for understanding the selection and evolution of metabolic pathways at the root of life.

---

When, in an ancient ocean, a handful of organic molecules formed an external boundary — the first cell membrane — a sharp distinction between an inside and an outside appeared for the first time. From that moment on, that primordial system had to invest energy to maintain this compartmentalization and to select, among the many chemical reactions that could occur, only a few metabolic pathways capable of exploiting valuable substances taken from the “outside” and transforming them into new products. Life was born together with this effort of compartmentalization and choice. 

Metabolic processes have a direct energetic cost, but they also require an “extra cost” to keep steering chemical flows into a preferred pathway rather than letting them disperse into all physically possible alternatives. Yet from the viewpoint of classical mechanics, compartmentalization and reaction selection — the “constraints” imposed at a system’s boundaries — should have no cost at all, as they are treated as fixed external conditions that do not contribute to entropy production.

Praful Gagrani, researcher at the University of Tokyo and first author of the new study, together with his colleagues — Nino Lauber (University of Vienna), Eric Smith (Georgia Institute of Technology and Earth-Life Science Institute), and Christoph Flamm (University of Vienna) — developed a method to calculate these overlooked costs to rank the pathways. This allows researchers to assess their biological efficiency — valuable information for evolutionary studies exploring how life emerged on our planet.

“What inspired the new work is that Eric Smith, one of the co-authors, used MØD, a software developed by Flamm and co-workers, to enumerate all the possible pathways that can ‘build’ organic molecules starting from CO₂.”

Gagrani refers to one of Smith et al.’s earlier studies on the Calvin cycle, a cycle of chemical reactions in photosynthesis that converts carbon dioxide into glucose.

“Eric used the algorithm to enumerate all the pathways that can make the same conversion that the Calvin cycle does, and then he used what we now call the maintenance cost in our paper to rank them.”

In this way, Smith et al. showed that the cycle used by nature lies among the least dissipative pathways — those with the lowest energetic cost. “Awesome, isn’t it?”, comments Gagrani.

Inspired by Smith’s work, Gagrani and colleagues devised a general method to estimate the thermodynamic costs of metabolic processes systematically. In their framework, the cell is imagined as a system crossed by a constant flow, where, for instance, one molecule (a nutrient) enters and another (a product or waste) exits. Given the underlying chemistry, one can generate all chemically possible pathways that convert the input into the output. Each pathway has its own “thermodynamic cost.” Instead of calculating energy in the classical sense, the method estimates how improbable it would be — in a world driven solely by spontaneous chemistry — to see the network (the set of molecules and reactions that convert input to output) behave in exactly that way.

This improbability has two components. The first is the maintenance cost, meaning how unlikely it is to sustain a constant flow through a certain pathway. The second is the restriction cost, which measures how unlikely it is to block all the alternative reactions in the network while keeping only the pathway of interest active.

The calculated improbability represents the cost of that process, which can then be used to classify metabolic pathways according to how “expensive” it is for the cell to keep one pathway active and silence the others.

“We saw things we didn’t expect, but that make sense once you think about them,” Gagrani explains. “For example, that using multiple pathways at the same time is less costly than using just one. Here’s an analogy: imagine four people who need to go from A to B through narrow tunnels. If each person has their own tunnel — four tunnels — they arrive more quickly than if there are only three or fewer, because two or more people would obstruct each other in the same narrow passage.”

In nature, however, we usually see that one process is favored over many. How is that explained? “It’s true, but in biological systems catalysis often intervenes — the action of facilitating molecules, enzymes — which accelerate reactions and make them less costly, achieving the same effect as having multiple pathways in parallel. This evolutionary choice happens because maintaining many pathways can have other drawbacks, such as producing many potentially toxic molecules.”

“Our method,” concludes Gagrani, “is a useful tool for studying the origin and evolution of life because it allows us to evaluate the costs of choosing and maintaining specific metabolic processes. It helps us understand how certain pathways arise — but explaining why those particular ones were selected requires a truly multidisciplinary effort.”

---

Journal

Journal of Statistical Mechanics Theory and Experiment

DOI

10.1088/1742-5468/ae22eb. 

Method of Research

Computational simulation/modeling

Article Title

Thermodynamic ranking of pathways in reaction networks

Article Publication Date

6-Jan-2026