Back in August 1969, Brenda Eskenazi hiked 15 miles in the pouring rain to reach the Woodstock Festival—but she never heard the music.

Eskenazi was so far back from the stage that she missed Janis Joplin, Jimi Hendrix, and the rest of the performers at that famous (and infamous) gathering in upstate New York. She did, however, see a young man on a very bad acid trip.

Watching him dive off the top of a car onto the cement, hallucinating water, the future scientist wondered: What on earth had happened to his brain to make him do that?

“That got me really, really interested in how chemicals affect the human brain,” she said in a recent interview.

The incident at the ‘60s most famous rock concert led Eskenazi to become a neuropsychologist and environmental epidemiologist, specializing on the impact of environmental exposures on children’s health. She joined the faculty of UC Berkeley School of Public Health in 1984 as an assistant professor in maternal and child health and epidemiology and became a professor in 1995. She was named Distinguished Jennifer and Brian Maxwell Professor of Maternal and Child Health in 2008.

A globe-hopping career

Eskenazi’s research has taken her all over the world, producing groundbreaking studies on the health hazards of exposure to pesticides, dioxins, metals, tobacco smoke, air pollution, and other toxic substances.

She has analyzed the aftermath of a chemical plant explosion near Seveso, Italy; studied what happened to workers exposed to benzene in China; and looked at in-utero DDT exposure in South Africa.

Eskenazi has also conducted research on the effects of social adversity and nutritional factors on male and female reproduction and on child development from the fetal stage to adolescence.

She is best known for building the Center for Environmental Research and Community Health (CERCH), a world-renowned science hub whose affiliated researchers have published hundreds of papers on environmental exposures and their impacts on pregnant women and children. Eskenazi became an emerita professor in 2019, but remains director of CERCH, which oversees the longest-running longitudinal birth cohort study of pesticides and other environmental exposures among children in any farmworker community in the world.

CERCH’s Center for the Health Assessment of Mothers and Children of Salinas, known as CHAMACOS, first enrolled pregnant women in 1999. Twenty-five years later, CHAMACOS is still a source of trailblazing research. Beyond their own investigations, the specimens and data that Eskenazi and her team have collected—initially from hundreds of pregnant women, and then from their children—serve as a lending library for researchers from around the globe.

When Eskenazi started her work, the fact that lead was a potent neurotoxin was beyond dispute. But the notion that pesticides and some other chemicals could also damage the developing brain was not as widely accepted.

Eskenazi’s investigators have produced some of the first evidence that the children who were exposed to pesticides in the womb had lower IQs than other children and other neuro-developmental problems. Their work showed that other chemical exposures were associated with lower birth weights, poor cognitive functioning, and additional health issues.

A massive impact

It’s hard to overstate Eskenazi’s contributions to environmental science. She has had an important impact on the regulation of chemicals at the state and federal level; on warnings about the risk of cancer, reproductive harm and birth defects now required under California’s Proposition 65; and on documents informing the Stockholm Convention, the historic international treaty to protect the public from persistent organic pollutants (toxic chemicals that resist degradation and can accumulate in living organisms).

“Brenda’s work has led the field of environmental epidemiology in designing and conducting longitudinal studies of key populations, from the Seveso Women’s Health Study to the CHAMACOS cohort, among many others,” said Linda Birnbaum, the former director of the National Institute for Environmental Science. “In addition, she’s a pleasure to collaborate with.”

Dr. Gwen Collman, director of the NIEHS office of scientific coordination, planning and evaluation, said, “Brenda is a brilliant researcher who has been very, very dedicated to expanding our knowledge base when it comes to the health effects of exposures to environmental chemicals. Her work has been very novel, very challenging. She’s not afraid to take on the tough stuff. She brings a very deliberate and rigorous approach.”

Eskenazi’s research has earned her many awards, most recently the 2023 Child Health Advocate Award from the Children’s Environmental Health Network. In 2014, she was inducted into the Collegium Ramazzini, a prestigious academy of the top 150 people in the world in occupational and environmental health. Her other honors include the John R. Goldsmith Award for Lifetime Achievement, from the International Society for Environmental Epidemiology.

Kim Harley, the faculty director of UC Berkeley’s Wallace Center for Maternal, Child and Adolescent Health, who first worked with Eskenazi on CHAMACOS in 2004 as a graduate student, praised her mentor’s innovation.

“If you look now, there are so many cohort studies and research looking at prenatal exposures and how they affect brain development,” Harley said. “But when she wrote that first grant back in 1998, there was hardly anybody doing it.

“The National Institutes of Health now has a toolbox of neurodevelopmental tests for this purpose, but none of this existed when Brenda started. She was one of the first to do this, and her PhD in neuropsychology put her in the perfect place to do it.”

From Queens to Yale

Eskenazi didn’t plan it that way.

Growing up in Queens, a borough of New York City, Eskenazi wanted to become either a surgeon or a medical illustrator. But while attending Queens College in the 1960s, her biology professor told Eskenazi that women didn’t belong in medicine. Lacking role models of female doctors, Eskenazi, at first, believed it.

Luckily, Queens College, a branch of the City University of New York, was the site of the entire university’s neuropsychology department, and Ezkenasi was welcome there.

“That was fascinating to me,” she said. “I happened to be in a good place for me, and it turned out by chance.”

Eskenazi was accepted to the CUNY doctoral program in neuropsychology, and then spent a pivotal year studying at the University of Leeds in England.

Her plan was to conduct electrical and chemical stimulation of animal brains, and study the effects. She worked on a range of animals, learning neurochemistry, neurophysiology and neuroanatomy. But soon, the head of her laboratory told her she had to stop operating because she didn’t have a license.

“You needed a license to operate on animals in England,” Eskenazi said. “And I didn’t have one. And it took a year to get a license. So I said, ‘What am I supposed to do?’ And he said, ‘Well, I guess you’re going to have to do human research.”’

She designed a study of cognitive issues in women using high-estrogen birth control pills.

“I wrote a questionnaire like an epidemiologist would, and that’s where the pieces came together. I entered into the field of epidemiology but without real training at that time.”

Eskenazi returned to the U.S., and received her PhD from CUNY Graduate Center in 1979, while also working at the Columbia University Psychiatric Institute. That led to an epidemiology and environmental health sciences postdoc at Yale University. By 1983, she was an assistant professor in Environmental Health Sciences at Yale School of Medicine, studying the neurotoxic as well as reproductive effects of many chemicals ranging from alcohol, nicotine and caffeine, to environmental chemicals. She moved to UC Berkeley School of Public Health in 1984.

The first class she taught at Berkeley was on reproductive hazards of industrial chemicals. And one of her first landmark studies was an investigation into the 1976 chemical factory explosion near Seveso, Italy, which exposed residents to high levels of 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD or dioxin), a human carcinogen and potent endocrine disruptor. She has followed the women exposed to dioxin from that disaster for more than two decades.

Tracking toxins in California’s salad bowl

An ongoing theme of her research has been the negative consequences of environmental agents on child health.

Much of Eskenazi’s most important research has come from CHAMACOS, the joint project she founded with Clinica de Salud del Valle de Salinas, Natividad Medical Center and other community groups in the Salinas Valley. This rich agricultural land is often called “the world’s salad bowl.” Dole is there, as is Naturipe Farms, Fresh Express, and since 1999, Brenda Eskenazi.

In 1996, the Food Quality and Protection Act was passed by Congress and this Act called for the protection of the health of fetuses and children from the effects of pesticides–that children were not “little adults.” In 1998, the Environmental Protection Agency and NIEHS put out a request to establish Centers for Children’s Environmental Health.

“We didn’t know very much information about children’s exposures and their effects, especially to pesticides, and how that affected child development,”’ Eskenazi said.

Eskenazi and her research team applied to establish one of these Children’s Centers to study the effect of short-acting pesticides on children.

“I said, ‘Look, we live in the largest agricultural state in the nation. We work at a land grant university. Our work needs to be on agriculture and it needs to be on pesticides,” Eskenazi said.

After forming partnerships with local health care providers, and community leaders—Eskenazi launched a birth cohort study, tracking mothers and children from primarily Mexican farmworker families who may have been exposed to pesticides used in the fields.

Her team recruited 600 women in the first half of their pregnancy. Half of these women had lived in the US less than five years, but at the time if you were pregnant you could receive MediCal, whether you were documented or not. They interviewed the women, collected maternal blood cord blood, and urine samples from them. They followed and examined their children soon after birth and at 6 months and every one to two years after. They did home walkthroughs and neighborhood assessments. They later added 305 additional children, who were followed from age 9.

As the children grew, researchers collected data on their neurodevelopment, including autism spectrum behavior; obesity, respiratory symptoms, onset of puberty and other health outcomes.

“Since I was a psychologist, I also made sure I got a lot of stuff on their social well-being and psychological well being as well as their full medical history,” Eskenazi said. Right after the 2016 Presidential election, we even collected information on their concerns about immigration policy. Another frequent subject has been gene-environment interaction, and more recently, the effects of exposure to environmental chemicals and social stressors on the epigenome of the developing child. Colleagues at UCSF and UC Berkeley have been following the health of the mothers, too.

They have been following many of the families for 25 years, ending up with more than 400,000 biological samples, fueling more than 200 studies on the impacts of pesticides and other chemicals on health as well as a myriad of other exposures; while at the same time, educating farmworker families and finding ways to reduce exposures.

In addition, the CHAMACOS has provided valuable information on the ubiquitous chemicals found in furniture, plastics, and cosmetics, and their effects on many aspects of health.

“When we started CHAMACOS, people were saying ‘Wow, this is a big undertaking, and it was really going to depend on the cooperation of the community,” said Kim Harley, who started as a student and later became study coordinator in 2004.

“From the very beginning, Brenda was really committed that the core of the study would be community-based participatory research. The staff was all bicultural, and bilingual, from the Salinas community.”

Gwen Collman, of NIEHS, praised Eskenazi for becoming part of the farmworker community, and spending the time necessary to develop and keep trust.

“The passion and connection that she has to the people in the Salinas Valley is so unique, impressive and inspiring,” Collman said. “She’s created an enormous treasure trove of information that we can mine, to look at many, many hypotheses. To this day, the CHAMACOS team is just knocking it out of the park.”

And to Collman, there was another tremendous benefit to CHAMACOS: It was a training ground for scores of Eskenazi’s former students, many of whom, like Kim Harley, and Asa Bradman, now at UC Merced, went on to become prominent environmental health researchers.

“She is so careful, not just teaching them how to do the research, but making sure every single paper is perfect,” Collman said. “I’ve gotten to know many of her trainees, and they are a wonderful group of scientists. Having Brenda as a mentor for even one year has been transformative for so many of them. She’s been an amazing leader.”

Harley said, “Working with Brenda totally defined my career. She was my mentor and continues to be my mentor. She’s been amazing. She helped me and encouraged me and enabled me to develop my own research portfolio and move into a faculty position at Berkeley, where I was able to start my own research program.”

Eskenazi believes that the mentorship role is one of the most, if not the most, important contribution a professor can make to science.

“I see my students and mentees as branches of a tree,” she said. “I train them and they train others—that is my biggest legacy.”

COVID-19 and a collaboration with Jennifer Doudna

At least it seemed that way, until the COVID-19 pandemic. As the disease emerged, Eskenazi recognized that the situations that farmworkers lived in—crowded conditions, difficulty getting medical care—made them especially vulnerable to the disease.

Quickly, she teamed up with her longtime CHAMACOS partners—Salinas Valley health clinics, agricultural companies and farmworker advocates—along with UC Berkeley Professor Jennifer Doudna, a Nobel Laureate in Chemistry.

Eskenazi and Doudna, the Li Ka Shing Chancellor’s Chair in Biomedical and Health Sciences, produced a study laying out the need for fast action to protect the agricultural workers. Their report, published in JAMA Open Network, motivated the state government to prioritize farmworkers for COVID vaccinations.

The result was an innovative van service that circulated around the Valley, inoculating farm workers against COVID and testing them and their families for the disease.

“Our coalition became a model for other counties in California and around the country,” she said. “Because of our work, farmworkers were prioritized for vaccination in many states.”

Overview

Evidence- and rights-based national policies, guidelines and legislation play a key role in improving sexual, reproductive, maternal, newborn, child and adolescent health (SRMNCAH), framing the enabling environment for equitable provision and accessibility of quality services. The SRMNCAH policy survey monitors the existence of national SRMNCAH laws, policies, strategies and guidelines and the extent to which they are aligned with WHO recommendations on SRMNCAH. This publication reports on the findings from the 2023 WHO SRMNCAH policy survey.

In the 2023 survey, which was completed by SRMNCAH focal points in each country’s ministry of health with support from WHO country offices and other national stakeholders, respondents completed modules on: (i) cross-cutting issues related to SRMNCAH; (ii) maternal and newborn health; (iii) child health; (iv) adolescent health; (v) sexual and reproductive health; and (vi) violence against women. The questionnaire was completed through a web-based platform that allows countries to submit national source documents (e.g., laws, policies, strategic plans, and guidelines) that were used to respond the survey. These documents are available through a searchable repository.

An online data visualization tool for the 2023 SRMNCAH policy survey can be accessed here.

Preterm birth trends in rates and numbers, 2010–2020

Preterm birth affects families in every country, on every continent. The past decade has seen mixed progress on collecting and acting on preterm birth data. Policy attention to a healthy start has increased, and the first global goal for neonatal survival was included in the Sustainable Development Goals (SDGs), with a linked target for stillbirths (Fig. 1) [2]. However, preterm birth has not yet directly been included in any high-level policies and measurement frameworks limiting the degree of political focus on reducing preterm birth. While there has been some evidence of an increase in the number of countries collecting data on preterm birth over the last decade, the highest number of countries reporting data is 60 countries. However, early ultrasound dating and innovations in gestational age assessment have improved measurement and some countries have strengthened their routine health information systems to better capture preterm birth rates (e.g. Brazil have improved preterm birth capture over the past 9 years) [3,4,5,6,7,8]. This highlights targeted efforts towards improving data that can be used for action.

Fig. 1 Data and estimates for preterm birth: timeline of progress over the past decade and vision for the next decade SDG – sustainable development goals; ICD – International Classification of Disease [9]. *SDG 3.2 and Every Newborn Action Plan (ENAP) targets to end preventable deaths of newborns and children under 5, with all countries reducing neonatal mortality rate to at least 12 per 1000 livebirths. There is also a linked ENAP stillbirth target reducing stillbirth rate [10, 11]. Preventing preterm birth and improving care for those born too soon is integral to achieving SDG 3.2 and ENAP mortality targets Full size image

Despite some technological advances, recent estimates by World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF) show no measurable progress in reducing preterm birth rates globally. Preterm birth rates were 9.9% (95% credible interval (CrI) [9.1, 11.2%]) in 2020, compared to 9.8% (95% CrI [9.0–11.0%]) in 2010 [12].There was also no measurable change in preterm birth rates in the highest-burden regions (Southern Asia: 13.3% (95% CrI [10.8–16.5%]) in 2010 and 13.2% (95% CrI [10.8–16.6%] in 2020, and sub-Saharan Africa: 10.1% in both 2010 and 2020 (95% CrI: [8.5–12.7%] in 2010, [8.6–12.7%] in 2020)) [12]. National-level preterm birth rates also changed little between 2010 (5.8%–16.5%) and 2020 (4.1%–16.2%).

Among 76 countries with robust time series data, 10 countries which reduced their preterm birth rates fastest were: Czechia, Austria, Brunei Darussalam, Singapore, Spain, Netherlands (Kingdom of the), Denmark, Hungary, Brazil and Sweden. All these countries reduced their preterm birth rates by more than 5 percentage points between 2010 and 2020, but it is important to note that this equates to an annual average reduction of only about 0.5 percentage points per year. In 14 countries (Russian Federation, Poland, Iceland, Croatia, United Kingdom of Great Britain and Northern Ireland, Bulgaria, Armenia, Bahrain, Ireland, Chile, Georgia, Colombia, the Republic of Korea and North Macedonia) the preterm birth rates increased by more than 5 percentage points in this period, although some of these increases may relate to improved data quality. In 52 other countries the preterm birth rate showed no measurable change (absolute percentage increase <1 percentage points).

The absolute number of babies born preterm decreased slightly from 13.8 million (95% CrI: [12.7–15.5 million]) in 2010 to 13.4 million (95% CrI: [12.3–15.2 million]) in 2020, primarily due to fewer births globally across many regions (Fig. 2) [12]. However, in sub-Saharan Africa the number of babies born preterm increased, with 563 000 more babies born preterm in 2020 than in 2010 (3.4 million (95% CrI: [2.8, 4.2 million]) in 2010, and 3.9 million (95% CrI: [3.3, 4.9 million]) in 2020. This relates to increases in the birth cohort in sub-Saharan Africa, as well as to the lack of reduction in preterm birth rates [12].

Fig. 2 Trends in annual number of preterm births by sustainable development goal regions, 2010–2020 Data from WHO/UNICEF preterm birth estimates, Ohuma, Moller, Bradley et al. [12]. Source: Lawn et al. [13] Full size image

Reported effects of the COVID-19 pandemic on preterm birth rates varied across contexts [14,15,16]. Whilst maternal COVID-19 infection may directly lead to preterm birth including through placental effects, direct impact of maternal systemic illness or vertical transmission, the pandemic was also associated with lower risk of other infections and reduced maternal stress potentially lowering the risk of preterm birth. [17] Obstetric care shifts may increase or reduce preterm birth rates. In published data, preterm birth rates were typically static or slightly increased. Some studies found this was associated with an increased risk of stillbirth, possibly attributed to reduced access to obstetric monitoring and interventions for fetal compromise. However, a meta-analysis of 32 studies and subgroup analysis of four studies found no significant impact on stillbirth rates (adjusted odds ratio (AOR) 1.08, 95% confidence interval (CI) [0.95, 1.23]) and AOR 1.06, 95% CI [0.81–1.38] respectively) [15].

Preterm rates and numbers in 2020

In 2020, an estimated 13.4 million (95% CrI: [12.3, 15.2 million]) live births were preterm, with 1 in 10 babies “born too soon” (9.9% of all live births (95% CrI: [9.1, 11.2%])). Preterm birth rates vary between regions, the highest occurring in Southern Asia, where 13.2% of babies were born preterm in 2020, compared to fewer than 8% of births in Eastern Asia, South- Eastern Asia, Northern America, Europe, Australia and New Zealand. However, sizeable national variations occur within regions. In Latin America, for example, preterm birth rates estimates for countries with available input data ranged from 5.8% (95% CrI: [5.4, 6.2%]) in Nicaragua to 12.8% (95% CrI: [8.0, 20.4%]) in Suriname [12].

There is also variation at the national level. According to global estimates in 2020, Bangladesh has the highest preterm birth rate (16.2%, 95% CrI: [11.8, 21.7%]), followed by Malawi (14.5%, 95% CrI: [9.5, 21.6%]) and Pakistan (14.4%, 95% CrI: [8.6, 23.1%]). Although the highest rates are predominantly in low- and middle-income contexts (Fig. 3), rates of 10% or higher persist in some high-income countries, such as Greece (11.6%, 95% CrI: [10.9, 12.3%]) and the United States of America (10.0%, 95% CrI: [9.6, 10.4%]). The nine countries that had the highest preterm rates in 2010 were the same in 2020, and in the same order. The countries with the lowest preterm rates were Serbia (4.1%, 95% CrI: [3.8, 4.4%]) and the Republic of Moldova (5.0%, 95% CrI: [4.0, 6.1%]) (Table 1) [12].

Fig. 3 Estimated national preterm birth rates and numbers in 2020 * Only national rates shown. CrI – Credible interval. Source: Adapted from WHO/UNICEF preterm estimates. Ohuma, Moller, Bradley et al. [12] Full size image

Table 1 Countries with preterm birth rate of 10% or higher in 2010 and 2020 Full size table

Almost half (45%) of all preterm births in 2020 occurred in just five countries: India, Pakistan, Nigeria, China and Ethiopia (Fig. 3) despite accounting for a lower proportion of the world’s live births. India had the highest number of preterm births in 2020 (3.02 million, 95% CrI: [2.2, 4.0 million]), accounting for more than 23% of all preterm births worldwide) with Pakistan, Nigeria and China each having more than three quarters of a million preterm babies in 2020. Countries with large numbers of preterm births reflect both larger numbers of total births, and higher preterm birth rates [12].

At the regional level, the largest burden of preterm birth remains in Southern Asia, where 4.8 million babies (95% CrI: [3.9, 6.0 million]) were born preterm in 2020, including more than 700 000 at <32 weeks, with the highest risks of mortality and long-term consequences (Fig. 4). Sub-Saharan Africa accounted for 3.9 million (95% CrI: [3.3, 4.9 million]) preterm births, almost 600 000 of them at <32 weeks [12].

Fig. 4 Preterm birth by gestational age and region in 2020 Data Source: Adapted from WHO/UNICEF preterm estimates. Ohuma, Moller, Bradley et al. [12] Full size image

In 2020, nearly 1.2 million preterm newborns are estimated to have been born in the 10 most fragile countries affected by humanitarian crises (Afghanistan, Chad, Central African Republic, Democratic Republic of the Congo, Myanmar, Somalia, South Sudan, Sudan, Syrian Arab Republic and Yemen) [18]. Many women and preterm babies in these settings face increased challenges in accessing care, especially higher-level care [19] The complete country, regional and global estimates can be found in Additional file 1.

Deaths and lifelong impacts for survivors of preterm birth

Neonatal conditions remain the fifth leading cause of death globally (after ischaemic heart disease, stroke, chronic obstructive pulmonary disease and lower respiratory tract infections) and the leading cause of loss of human capital (e.g. Disability-adjusted life years (DALYS)) [20].

This high burden of DALYs from neonatal conditions is due primarily to deaths at an early age. Preterm birth complications are the leading cause of mortality among children under five years of age, as well as a leading risk factor for other causes of death such as infections [21]. Almost a million children (0.9 million) were estimated to have died due to direct complications of preterm birth in 2022, and over a third of all neonatal deaths worldwide are estimated to be due to direct complications of preterm birth [21].

Inequalities in care between and within countries result in unacceptably large survival gaps for babies born preterm. While higher-resourced settings have near-universal survival for those born over 28 weeks’ gestation, mortality rates remain high in areas where access to care is limited, even for babies born up to 32 weeks’ gestation. Resulting in substantial regional variations in preterm survival (Fig. 5). These numbers reflect continued stagnation in preterm birth rates and missed opportunities to improve care for preterm babies [19, 21].

Fig. 5 Regional variation in the proportion of preterm births resulting in neonatal deaths in 2020 In each pie chart darker shading in indicates proportion of preterm births with neonatal death (first 28 days), by region. Data sources: Preterm birth numbers by country from Ohuma et al. [12]. Mortality estimates generated by applying country specific 2019 preterm cause-specific neonatal death proportions from Perrin et al. [22] to 2020 country-specific live birth estimates from World Population Prospects (https://population.un.org/wpp/) [23] Full size image

Preterm birth is also associated with long-term health consequences in survivors, including respiratory and cardiovascular complications and neurodevelopmental impairments. These impairments can vary from major disabilities, such as diplegia, particularly for those born the most preterm, to less severe outcomes. Importantly, new research shows that being born even a few weeks preterm can increase the risk of learning and behavioural spectrum disorders. Since most preterm births (85%) occur between 32 and 37 weeks, a significant portion of preterm babies are at risk, contrary to previous assumptions that only extremely preterm born babies were vulnerable. Importantly, even those born at between 37 and less than 40 weeks have a slightly elevated risk of death and an elevated risk of adverse neurodevelopmental outcomes, notably behavioural conditions compared to babies born at term [22, 24, 25].

Disability-free survival is a sensitive marker of the quality of care provided to preterm babies. Many impairments associated with preterm birth, including blindness and visual impairment due to retinopathy of prematurity, are preventable. Recent decades have witnessed an increase in retinopathy of prematurity cases, particularly in East and South Asia, even among moderately preterm infants [26, 27]. Improving safe oxygen use and expanding screening and treatment programmes in parallel with increased access to inpatient neonatal care is essential to avoid a repeat of the epidemics of blindness previously observed in Western Europe, the United States, and Latin America [26].

These outcomes impact not only the individuals born too soon, but also their families, caregivers, communities, healthcare systems and wider society [28].

Overview

This resource is the standardized WHO glossary of the following terms:

Public health data terms: Including those related to collection, disaggregation, analysis and management of public health data.

Statistical terms: Incorporating the most common statistical methods used to analyse public health data and health indicators.

Health indicator terms: Comprising terminology related to health indicators such as definitions, classification and validation.

The terms are first listed in alphabetical order and then according to related thematic areas.

Key facts

Over 1.5 million adolescents and young adults aged 10–24 years died in 2021, about 4500 every day.

Young adolescents aged 10–14 years have the lowest risk of death among all age groups.

Injuries (including road traffic injuries and drowning), interpersonal violence, self-harm and maternal conditions are the leading causes of death among adolescents and young adults.

Half of all mental health disorders in adulthood start by age 18, but most cases are undetected and untreated.

Early onset of substance use is associated with higher risks of developing dependence and other problems during adult life, and younger people are disproportionately affected by substance use compared with older people.

Globally, there were 42 births per 1000 to girls aged 15–19 years in 2021.

Overview

Survival chances for adolescents and young adults vary greatly across the world. In 2021, the average probability of a 10-year-old dying before age 24 was about 6 times higher in sub-Saharan Africa than in North America and Europe.

Within the age group 10–24 years, mortality rates are lowest among adolescents aged 10–14, and highest among young adults aged 20–24 years. Females generally have lower mortality rates for these ages than males.

The patterns of death of 10–14-year-olds are dominated by infectious diseases. Among older adolescents and young adults, a shift away from infectious diseases of childhood is seen, towards accidents and injuries, self-harm and interpersonal violence. Sex differences in mortality rates also become apparent in adolescence.

Main health issues

Many unintentional injuries such as road traffic and drowning are the leading cause of death and disability among adolescents.

Physical activity

Globally, in 2016, only 1 in 5 adolescents are estimated to meet WHO guidelines on physical activity. Prevalence of inactivity is high across all WHO regions, and higher in female as compared to male adolescents (8).

Rights of adolescents

The rights of children under 18 years to survive, grow and develop are enshrined in international legal documents. In 2013, the Committee on the Rights of the Child (CRC) published guidelines on the right of children to the enjoyment of the highest attainable standard of health, and a General Comment on realizing the rights of children during adolescence was published in 2016. It highlights states’ obligations to recognize the special health and development needs and rights of young people.

The Convention on the Elimination of Discrimination Against Women (CEDAW) also sets out the rights of women and girls to health and adequate health care.

WHO response

WHO works with Member States and partners to improve the health of young people by producing evidence-based guidelines, advocating and providing recommendations for adolescent-responsive health systems, and documenting progress in adolescent health and development.

In 2023, WHO published an update of the Global Accelerated Action for the Health of Adolescents (AA-HA!): Guidance to support country implementation. AA-HA! 2.0 has drawn on inputs received during consultations with Member States, United Nations agencies, adolescents and young people, civil society and other partners. It aims to assist governments in deciding what they plan to do and how they plan to do it as they respond to the health needs of adolescents.

To improve adolescent health measurement globally, WHO in collaboration with UNAIDS, UNESCO, UNFAP, UNICEF, UN Women, the World Bank Group, and the World Food Programme (WFP), has established the Global Action for Measurement of Adolescent health (GAMA) Advisory Group. A comprehensive set of 47 priority indicators for global, regional and national adolescent health measurement has been published in 2024 using a structured participatory process.

References

United Nations Office on Drugs and Crime. Drug use and consequences. 2020. https://wdr.unodc.org/wdr2020/field/WDR20_Booklet_2.pdf Ma, Chuanwei et al. Prevalence and trends in tobacco use among adolescents aged 13–15 years in 143 countries, 1999–2018: findings from the Global Youth Tobacco Surveys. The Lancet Child & Adolescent Health, Volume 5, Issue 4, 245 – 255. https://www.thelancet.com/journals/lanchi/article/PIIS2352-4642(20)30390-4/abstract UNAIDS. https://aidsinfo.unaids.org/ UNICEF. Adolescent HIV prevention. https://data.unicef.org/topic/hivaids/adolescents-young-people/ Brisson, Marc et al. Impact of HPV vaccination and cervical screening on cervical cancer elimination: a comparative modelling analysis in 78 low-income and lower-middle-income countries. The Lancet, Volume 395, Issue 10224, 575 – 590. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30068-4/fulltext United Nations Department of Economic and Social Affairs. World population prospects 2024. https://www.un.org/development/desa/pd/world-population-prospects-2024 Abarca-Gómez, Leandra et al. Worldwide trends in body-mass index, underweight, overweight, and obesity from 1975 to 2016: a pooled analysis of 2416 population-based measurement studies in 128.9 million children, adolescents, and adults. The Lancet, Volume 390, Issue 10113, 2627 – 2642. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2817%2932129-3/fulltext Guthold, Regina et al. Global trends in insufficient physical activity among adolescents: a pooled analysis of 298 population-based surveys with 1·6 million participants. The Lancet Child & Adolescent Health, Volume 4, Issue 1, 23 – 35. https://www.thelancet.com/article/S2352-4642(19)30323-2/fulltext