Impact

Another Reason to Get Teens Moving

Active girls may experience breast cancer protection from exercise

As the risk of breast cancer rises among young women and population levels of physical activity decline, researchers at Columbia Mailman School of Public Health are reporting an intriguing link: Recreational physical activity may be associated with differences in breast tissue composition and biomarkers of stress in adolescent girls. The new study, conducted in partnership with the Herbert Irving Comprehensive Cancer Center, was published in the journal Breast Cancer Research.

Girls who reported engaging in at least two hours of recreational physical activity in the prior week, compared with none, had lower percent water content in breast tissue—an indicator of lower breast density. They also had lower concentrations of urinary biomarkers linked to stress. (Some research suggests that the effects of chronic stress on the neuroendocrine system may promote tumor growth.) The findings align with previous research in adult women showing that more physical activity is associated with less dense breasts. The most active adult women have a 20 percent lower breast cancer risk than the least active ones. Until now, however, the biological mechanisms underlying this association—particularly earlier in life—have remained poorly understood. “Our findings could have important implications for breast cancer risk reduction,” says Rebecca Kehm, PhD, assistant professor of Epidemiology.

Unfortunately, 51 percent of the teens in the study reported no recreational physical activity in the past week. The girls’ average age was 16, and 64 percent were Hispanic. “Importantly, this research was conducted in a cohort of urban Black/African American and Hispanic girls—groups that are historically underrepresented in research and face persistent disparities in physical activity levels and breast cancer outcomes,” says Mary Beth Terry, PhD, professor of Epidemiology (in Environmental Health Sciences). 

Progress on the Genetics–Cancer Connection 

Biostatistics techniques have helped to yield a major advance in understanding how human and viral genomes interact to shape disease risk. Researchers report in Nature that variations in the Epstein–Barr virus (EBV), together with a specific immune-related gene (HLA-A*11:01), strongly influence the risk of nasopharyngeal cancer.

Although EBV infects more than 95 percent of adults worldwide, only a small fraction develop EBV-associated cancers, making it critical to understand how host and viral factors jointly influence disease. Zhonghua Liu, ScD, assistant professor of Biostatistics, who led the study’s statistical design and analysis, explains that rather than analyzing the human host and viral genetic variation separately, the researchers examined human genome-wide association data alongside EBV whole-genome sequencing. This allowed a systematic search for genetic interactions across both genomes. The results show that cancer risk is shaped not by host genetics or viral strain alone, but by their combined effects. Individuals with a susceptible genetic background infected with EBV strains carrying a particular 85841G variant face substantially elevated risk.

Trees, Please

More robust tree canopy cover is linked to a lower incidence of falls injuring pedestrians, shows a new study. Trees’ cooling power likely guards against the effects of high temperatures; it also helps prevent road and sidewalk damage that contributes to falls.

Children’s Online Risk Keeps Growing

Despite increased efforts to tackle child sexual abuse and exploitation, online risks to children have grown since 2023, shows a new report with analyses by researchers at the Care and Protection of Children (CPC) Learning Network in the Heilbrunn Department of Population and Family Health. Artificial intelligence has contributed to an explosion in the creation and distribution of child sexual abuse material. Perpetrators are also adapting to utilize end-to-end encryption platforms to evade detection. 

The WeProtect Global Alliance’s Global Threat Assessment 2025 offers guidance for technology companies, governments, and other organizations. It also warns that future changes to the digital landscape have significant potential to affect safety, given that the majority of children in 55 countries start using a digital device before age 10. “The report provides a powerful action-oriented framework for tackling this complex global threat,” says Cassie Landers, EdD, MPH, assistant professor of Population and Family Health and the director of the CPC Learning Network. 

Abortion Restrictions: A Depression Link

Restrictive abortion policies are tied to higher levels of depressive symptoms among women in the general population, according to a new national study of almost 20,000 women reviewing 25 years of data. The equivalent of four additional restrictive laws was linked to a 7 percent increase in depressive symptoms.

Abortion is a common and safe healthcare service that most Americans support under many circumstances. “Legislation restricting abortion is well known to worsen birth outcomes and women’s physical health and even lead to a rise in female mortality,” says Sarah McKetta, MD/PhD ’22, assistant professor of Epidemiology. This study counters misinformation linking abortion with adverse mental health and suggests that legal protections for reproductive healthcare may benefit mental health.

Researchers adjusted for factors such as race and ethnicity, age, and income inequality. “We also assessed [the rate of] motor vehicle crashes and examined male respondents, and found no significant link,” notes McKetta. “This reassured us that the associations seen are unlikely to be due to confounding factors.”

The data predated the June 2022 Dobbs ruling. Dramatic shifts in the legal landscape following the Dobbs decision, after which many states enacted even more restrictive laws, have likely only intensified the negative effect. 

Cleaner Air, Sharper Minds

As prenatal air pollution exposure declined in New York City, measures of children’s cognitive development improved, report researchers at the Columbia Center for Children’s Environmental Health (CCCEH). Between 1998 and 2016, average fine particulate matter and nitrogen dioxide concentrations measured at pregnant individuals’ residences decreased by 32 percent and 30 percent, respectively. Between 1998 and 2020, the concentration of polycyclic aromatic hydrocarbons the pregnant people were exposed to fell 60 percent. These changes were largely driven by the city’s Clean Fuel Bus Program, Clean Air Taxi legislation, Clean Heat Program, and Climate Mobilization Act.

Tracking participants’ offspring, researchers found a 26 percent increase in Mental Development Index scores at age 3 in the first versus the latest cohort of children, concurrent with declining air pollution. “This study in over a thousand children over twenty years provides new evidence that policies to reduce fossil fuel emissions benefit developing brains,” says CCCEH founder Frederica Perera, DrPH’82, PhD ’12, special research scientist and professor emerita
of Environmental Health Sciences. 

A Simple Email for Safer Medicines

Reminder emails substantially increase clinicians’ use of a database supporting safe prescribing of opioids and other drugs. Databases called Prescription Drug Monitoring Programs (PDMPs) track prescribing of opioids and other tightly regulated medications. All U.S. states operate them, and most require clinicians to make accounts and check the system before prescribing opioids. Yet compliance remains uneven.

Researchers focused on 7,872 physicians and physician assistants who were not meeting state requirements to hold a PDMP account or search the system before prescribing, assigning them to receive emails or not. Emails significantly increased PDMP engagement, including account creation, searching, and searching for patients with a history of risky prescribing. Emails emphasizing clinicians’ legal requirement to use the PDMP more than tripled engagement. Emails highlighting benefits to patients were also effective, but less so. Neither email had detected effects on prescribing practices, but just getting clinicians to make accounts and check the PDMP could translate to safer and better-informed care.

“Email is a low-cost, scalable intervention that could serve as a template for efforts to promote other best practices in healthcare, too,” says Adam Sacarny, PhD, associate professor of Health Policy and Management. The study appears in JAMA Health Forum.

Warming Temperatures May Lead to Violence

As temperatures rise, violence-related hospital visits increase—including visits for both interpersonal and self-inflicted violence—according to a new analysis of 14 years of Medicaid claims data published in Communications Sustainability. A 5°C increase was associated with a 1.5 percent increase in interpersonal violence visits and a 3.7 percent increase in self-inflicted violence visits. Warmer temperatures and increased outdoor time correlate with more frequent face-to-face interactions. Higher temperatures also increase outbursts of temper. Reduced quality and length of sleep resulting from overheating can result in irritability, particularly in homes that lack air conditioning. Greater consumption of alcohol and drugs in higher temperatures may also contribute.

“Our results emphasize the importance of integrating mental health into climate change preparedness,” says Robbie M. Parks, PhD, assistant professor of Environmental Health Sciences. Individuals with lower incomes may be especially likely to be affected by the heat due to a lack of home air conditioning; they also have limited access to mental healthcare. “Investment in programs to mitigate the impacts of high temperatures can foster a safer and more resilient society,” Parks adds. 

IN MEMORIUM 

Phyllis Mailman: A Woman of Impact

The Columbia Mailman community mourns the passing of Phyllis Mailman, holding up her legacy of kindness, leadership, and unwavering commitment to public health, medicine, higher education, and the arts. In 1998, Mrs. Mailman and her family made a transformative gift to the School, then known as the Columbia University School of Public Health. At the time, the family’s gift was the largest single gift ever made to a public health school in the United States. In recognition of the Mailman family’s historic contribution, the School was renamed the Joseph L. Mailman School of Public Health, in honor of Mrs. Mailman’s late husband.

Mrs. Mailman played an unparalleled role in helping to shape Columbia Mailman’s mission and impact by providing scholarship funding, supporting School-wide programs, and serving on the School’s Board of Advisors for almost three decades. A natural philanthropist skilled with keen leadership and an innovative spirit, in 2011 she created the School’s biennial gala, which she led tirelessly. Through the years, Mrs. Mailman grew the gala’s impact, building strong networks of friends for the School. Her children, Jody Wolfe and Joshua Mailman, have also been long-standing supporters of the School and members of its Board of Advisors.

Her leadership and generosity helped propel world-class educational programs, faculty advancement, groundbreaking research, and innovative public health solutions. The Phyllis Mailman Professorship of Public Health, co-established in perpetuity by her family and held by a distinguished researcher in the Center for Infection and Immunity, positioned the School to attract and retain talented faculty members. Her work on behalf of the School helps ensure it will continue to define public health excellence well into the next century. 

This article was first published in the 2026-2027 issue of Columbia Public Health Magazine.