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21st Century Science

Carrying a Heavy Load

Whether helping adults transition to living in their community after being released from the California prison system or designing the first nationally representative survey of CBD users, the Herbert Wertheim School of Public Health and Human Longevity Science is leveraging existing research strengths at UC San Diego to build programs that address key 21st century public health challenges.

In the ’21-’22 academic year, researchers at the Herbert Wertheim School of Public Health were awarded numerous grants to launch new research programs or advance established projects including the study of epigenetic aging biomarkers to predict the risk of Alzheimer’s disease and related dementias and a project to develop social and behavioral research to better understand how to promote the voices of local people within low- and middle-income communities globally.

These projects are indicative of the depth of the Herbert Wertheim School of Public Health’s five strategic research priorities: climate and environmental health, global health justice and health equity, healthy births and aging, and longevity science, health services research, and mental health and substance use.

Climate and Environmental Health

ESPINA: The Study of Secondary Exposures to Pesticides Among Children and Adolescents

One of the greatest concentrations of rose plantations in the Americas is nestled in Pedro Moncayo, a county in Ecuador. However, among this beauty lies an unseen danger: pesticides used in floriculture that seep into groundwater or drift in the air from agricultural crops onto nearby homes.

“Many chronic diseases and mental health disorders in adolescents and young adults have increased over the last two decades worldwide, and environmental contaminants may explain a part of this increase,” said principal investigator Jose Ricardo Suarez, M.D., Ph.D., M.P.H., associate professor in the Herbert Wertheim School of Public Health.

“Hundreds of new chemicals are released into the market each year, and over 80,000 chemicals are registered for use today. Sadly, very little is known about the safety and long-term effects on humans for most of these chemicals.”

Exposure to some of the most used insecticides worldwide is linked to altered neurocognitive performance while other insecticides may also affect mood and brain development. Today, 20% of adolescents and 26% of young adults have a diagnosable internalizing disorder such as anxiety and depression or an externalizing problem such as aggression and conduct disorders.

In 2008, Suarez started ESPINA: The Study of Secondary Exposures to Pesticides Among Children and Adolescents, a prospective cohort study funded by the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health, the National Institute of Occupational Safety and Health, and other private funding sources, aimed at understanding the effect of pesticide exposures on the development of children in agricultural settings.

Underway since 2008, 623 boys and girls have been examined. In 2022, Suarez and his team completed the 14th yearly follow-up exam on study participants during July and August. With a growing biorepository expected to exceed 50,000 samples in 2022, this is the largest study of children to assess short-term effects of pesticide exposures and among the largest to assess the long-term effects of pesticide exposures on child development.

Since joining UC San Diego in 2013, Suarez has welcomed involvement of other school of public health faculty including Harvey Checkoway, Ph.D., M.P.H., Suzi Hong, Ph.D., Georgia Kayser, Ph.D., Camille Nebeker, Ed.D., M.S., and Xin Tu, Ph.D., as well as students and Ariel Feldstein, M.D., professor in the UC San Diego School of Medicine.

In May 2022, Suarez and Raeanne C. Moore, Ph.D., associate professor in the UC San Diego School of Medicine, received a $3-million NIEHS grant to conduct an ancillary study within ESPINA to understand whether seasonal exposures to pesticides may result in short- and long-term alterations in cognitive performance and mood in adolescents and young adults. This study uses smartphone technologies to assess real-life cognitive performance and mood over 2.5 years, building on the 14-year follow-up examination of the ESPINA study.

“Identifying which pesticides may be considered unsafe for humans will advance this understudied field of research and will have significant public health and equity implications for agricultural populations globally,” said Suarez.

Global Health Justice and Health Equity

Aging for All

To better understand and promote agency for individuals, communities and local organizations in low- and middle-income countries, the United States Agency for International Development (USAID) awarded the Center on Gender Equity and Health at UC San Diego School of Medicine and the Herbert Wertheim School of Public Health a $38-million grant to fund “Agency for All,” a five-year project.

Agency for All is intended to develop and foster social and behavioral research resulting in a better understanding of how to promote the voices of local people within their own communities and within health and development programming.

The goal of Agency for All resonates with the aim of the Herbert Wertheim School of Public Health to develop and implement solutions to reduce and eliminate disparities in resource-challenged communities, said Holly Baker Shakya, Ph.D., technical lead for research on the project.

“Our work in Agency for All is focused on empowering communities to identify and achieve their own goals for improved health and well-being,” said Shakya, associate professor at the Herbert Wertheim School of Public Health. “We aim to do this within an environment of equity- to reduce the colonial dynamics of health and development work and elevate the voices of local organizations and communities.”

Agency for All addresses multiple dimensions of health and well-being, including maternal and child health, infectious disease, HIV/AIDS, family planning and reproductive health. The program will work with diverse populations across the globe, with a focus on Africa and South Asia.

“As a key ethic of our program is locally led research, one of my most important jobs is to ensure that we are asking the right questions of the right people to ensure that research activities are responsive to local priorities and realities,” said Shakya.

The initiative will concentrate on three geographical areas or hubs in East Africa, West Africa, and South Asia, collaborating with specific organizations and networks in those regions. These partners include the Centre for Catalyzing Change (India), Evidence for Sustainable Human Development Systems in Africa (Cameroon), Makerere University (Uganda), Matchboxology (South Africa), Sambodhi (India), Shujaaz, Inc. (Kenya), University of Witwatersrand (South Africa), CORE Group, International Planned Parenthood Federation, Promundo-US, Save the Children and Viamo.

My work is a step toward understanding whether epigenetic age acceleration is a biomarker of biological aging that can predict future risk of Alzheimer’s disease and related dementias”

Aladdin H. Shadyab, Ph.D., assistant professor at the Herbert Wertheim School of Public Health.

Human Longevity Science: Healthy Births and Aging

Epigenetic Aging Biomarkers of Mild Cognitive Impairment, Alzheimer’s Disease and Related Dementias, and Brain Aging

In the United States, 1 in 3 seniors dies with Alzheimer’s or another dementia, and more than 6 million Americans are living with the disease, according to the Alzheimer’s Association. Alzheimer’s disease kills more people than breast cancer and prostate cancer combined.

“If we can slow biological aging, we may be able to prevent multiple diseases and conditions that affect older adults simultaneously. My work is a step toward understanding whether epigenetic age acceleration is a biomarker of biological aging that can predict future risk of Alzheimer’s disease and related dementias,” said Aladdin H. Shadyab, Ph.D., assistant professor at the Herbert Wertheim School of Public Health.

“We will investigate whether epigenetic age acceleration is associated with higher risk of Alzheimer’s disease, with the long-term goal of determining whether targeting epigenetic aging could slow or prevent the development of Alzheimer’s disease. We also want to identify age-associated epigenetic mechanisms of dementia as possible therapeutic targets,” said Shadyab, whose work is at the intersection of geroscience, longevity science and multiomics.

Chronological age is based on a person’s birthdate. Epigenetic aging refers to the biological age of a person’s cells, tissues and organ systems. If biological aging occurs faster than an individual’s chronological age, the person is undergoing epigenetic age acceleration, which is associated with higher risk of cancer, cardiovascular disease, Parkinson’s disease, and other diseases.

Research on the role of epigenetic aging on cognitive and brain health is limited. Shadyab and colleagues have added to data with research published in peer-reviewed journals like the August 2021 paper identifying an association with epigenetic age acceleration and cognitive impairment among women who developed coronary heart disease.

That same month, the National Institute on Aging, part of the National Institutes of Health, awarded Shadyab a $2.1 million grant for a project that will evaluate blood-based epigenetic aging biomarkers for predicting risk of mild cognitive impairment, Alzheimer’s disease and related dementias, cognitively healthy longevity, and accelerated brain aging.

For this research, Shadyab is gathering data from the Women’s Health Initiative Memory Study which will supply blood samples for epigenomic profiling in more than 6,000 women. Because the data will be made available to the scientific community for studying the epigenomics of various age-related diseases such as cardiovascular diseases, cancer, and diabetes, as well as healthy longevity, the data could have a broad public health impact, said Shadyab.

“What’s important when we talk about human longevity science and geroscience is that we’re not just interested in lifespan — the length of someone’s life — but rather the ultimate goal is to identify strategies that can extend health span in older adults,” said Shadyab.

Health Services Research

UC San Diego RELINK Program

In 2016, facing an overwhelmed prison system, California voters passed Proposition 57 to allow incarcerated people convicted for nonviolent crimes to reduce their sentence by earning credits for sustained good behavior and participation in rehabilitation.

Although the prison population has been dropping yearly, continued overcrowding and concerns with the impact of COVID-19 outbreaks, the California Department of Corrections and Rehabilitation expanded the good behavior program to make more incarcerated people eligible to earn credits and therefore shorter sentences.

“State policy now says that a lot of people currently in prison should no longer be incarcerated. The result is that people with 10 to 30 years of prison history are returning to their communities and need help navigating re-entry to daily life,” said Victoria Ojeda, Ph.D., M.P.H., UC San Diego RELINK principal investigator and professor at the Herbert Wertheim School of Public Health.

Formerly incarcerated people who are moving back into the community are known as reentrants. After lengthy sentences they may not know how to obtain help finding work, housing or health care. They may also face persistent stigma.

While there are programs available to assist, many programs may limit how long individuals may access services after their release from prison or jail.

That’s where the UC San Diego RELINK program comes in.

RELINK serves adult reentrants living in three underserved regions of San Diego County — Central, South and East County — by using evidence-based approaches to tackle basic, vocational and health needs through service navigation, warm-handoffs to community providers, and skill-building mentorship to enhance pro-social behaviors.

“We cannot solve our clients’ concerns in a short period of time and needs may change over time, so we keep our doors open to our clients whenever they need us,” said Ojeda. “They can come back to fine-tune the support they are getting from our team.”

In July 2021, the UC San Diego RELINK Program received a grant from the California Board of State and Community Corrections through the Adult Reentry Grant Program Warm Handoff Reentry Services to provide services to reentrants 18 years and older. The program began serving clients in January 2022.

“Through this program, we hope to act as a safety net individuals with limited or no access to resources. One of our goals is to determine if providing tailored support will keep people from returning to prison,” said Ojeda, who previously ran a similar program for transition age youth (18 to 26 years old) funded by the U.S. Department of Health and Human Services Office of Minority Health.

When Ojeda arrived at UC San Diego in 2007 her research was focused on migration and health. Her research revealed that there was a critical need for helping people who had histories of incarceration and needed assistance accessing resources that might help them successfully re-enter their communities.

“The Herbert Wertheim School of Public Health aims to improve the health of the region by addressing health and social disparities. This research helps reach a community that has high level needs that are often neglected,” said Ojeda. “By helping these individuals, the entire community is benefiting.”

Mental Health and Substance Use

Characterizing the Epidemiology of Cannabidiol (CBD) Use Among U.S. Adults

Eric Leas, Ph.D., M.P.H., focused his research on tobacco regulation while studying for a doctorate in public health at UC San Diego. During that period there was a groundswell of support for the adoption of recreational cannabis laws across the U.S., sprouting a new research interest.

“First, I looked across at the cannabis marketplace and saw that many of the best practices in tobacco regulation were not being applied,” said Leas, now an assistant professor at the Herbert Wertheim School of Public Health.

“However, cannabis and tobacco are not entirely the same products. Many people think of cannabis as a medicine, but we rarely think of tobacco in this way. This distinction creates this creates a need for research into how people are using cannabis products and how best to regulate them.”

Thanks to a K01 grant he was awarded in April 2022 from the National Institute on Drug Abuse, part of the National Institutes of Health, Leas’ goal is to create the first nationally representative survey of CBD users to describe who is using CBD, why they’re using it, and whether adverse events were experienced.

CBD is a non-psychoactive chemical that can be extracted from cannabis plants including hemp, which is a cannabis plant that does not contain delta-9-THC, the main psychoactive chemical in cannabis. While recreational cannabis is legal in 19 states, Washington D.C., and Guam, CBD is currently legal in every U.S. state because of distinctions in the regulation of hemp and cannabis.

CBD products are now available in a wide variety of forms including edibles, topicals, vaping products and even dog treats. These can be sold in convenience stores and online.
CBD products have become popular in part because of claimed medical benefits. Because of this marketing, many consumers have become reluctant to see it in a negative light. Instead, they see it as harmless.

But the speed of their arrival on the market, their popularity and inconsistent regulation is cause for some concern among public health experts, said Leas.

“One of the concerns is the lack of requirements for labeling practices and testing for consistency,” said Leas.

“There are several studies that show most CBD products on the market are off label, so you could be getting much more or much less of a dose of CBD than you expect. Additionally, even when they are labeled as THC-free, some CBD products on the market may also include THC, which could lead to unintended highs.”

Leas is not calling for CBD and cannabis products to be pulled from the shelves. He wants regulation to catch up with the market so that products are safer, and consumers are educated on what, if any, health benefits are offered.

In a study published in JAMA Network Open in October 2020, Leas and co-authors concluded that consumers believed CBD could be used to treat many medical conditions that have not been scientifically proven applications of CBD. The authors suggested a public health campaign to encourage consumers to talk to their health care teams before self-medicating and restrictions on unproven marketing claims.

In October 2021, Leas authored an opinion piece in the American Journal of Public Health discussing the need to address policy loopholes that allow for the production and sale of delta-8-THC, a psychoactive substance that is also being sold with few marketing restriction. Like CBD products, delta-8-THC products are frequently mislabeled and can contain toxic chemicals that are not listed on labels.

“The ultimate goal of this research is to make a safer marketplace for cannabis products and hopefully better inform consumers more about appropriate applications of the products,” said Leas.

—Yadira Galindo