Archives: News

Add Health is excited to announce the release of three new biomarker datasets:

• Wave VI Biomarker Weights
• Wave VI Renal Function
• Wave VI Neurodegeneration

In addition, we are releasing two new Mortality Outcomes Surveillance datasets:

• Mortality Outcomes Surveillance: Coroner/Medical Examiner Report Data, 2018 Update
• Mortality Outcomes Surveillance: Death Certificate Data, 2018 Update
  

For additional recently released datasets, please visit the File Inventory. 

Please note that Mortality Outcomes Surveillance: Death Certificate Data, 2018 Update is a Special Request dataset, and is only available to SRW to users who have an existing SRW contract and who have signed the Add Health Data Access Agreement. For more information, please see the requirements for using this dataset. 

The three biomarker datasets and the Mortality Outcomes Surveillance: Coroner/Medical Examiner Report Data, 2018 Update data available to users with SRW or Home Institution contracts. The files are already available on the SRW and will be available soon to Home Institution users. For more information on the SRW and Home Institution contract options, please visit the Restricted-Use Contract Options page.

Using nationally representative data from Waves I, II, IV, and V of the National Longitudinal Study of Adolescent to Adult Health (Add Health), Dr. Kim et. al. examined the impact of loneliness during adolescence on health and well-being later in adulthood. Loneliness was measured with a survey question asking how often participants felt lonely in the past week, with response options ranging from “never” to “most or all of the time.” Investigators examined whether this loneliness increased between Waves I and II, when participants were approximately 15 years old. Including covariates, researchers assessed over 40 health outcomes in Waves IV and V, when participants were approximately ages 28 and 37, spanning physical health, behavioral health, mental health, social factors, and civic and prosocial behavior.

The research team found that the participants experiencing more loneliness in their adolescent years had worse mental health outcomes, psychological well-being outcomes, and social outcomes but not physical health outcomes, health behavior outcomes or civic and prosocial outcomes. These results suggest that increases in adolescent loneliness are associated with worsened mental and socio-emotional aspects of adult health. However, because follow-up occurred at relatively young adult ages, additional physical health complications may emerge later in life.

To read the full article click the link below. For more important findings using Add Health data, visit the Add Health publications page.

Kim, Eric S., et al. “Loneliness During Adolescence and Subsequent Health and Well-Being in Adulthood: An Outcome-Wide Longitudinal Approach.” Journal of Adolescent Health, vol. 77, no. 1, July 2025, pp. 66-75. https://doi.org/10.1016/j.jadohealth.2024.12.011.

Add Health is excited to announce the following data are now available:

Wave V Epigenetic Clocks: Biological aging measures were derived from DNA methylation data for 4,626 unique study participants based on blood collected during the Wave V home exam. The measures include Horvath, PhenoAge, GrimAge, DunedinPACE, Principal Component clocks, and cell type proportion estimates.

For additional recently released datasets, please visit the File Inventory. These data are only available to users with SRW or Home Institution contracts. The files are already available on the SRW and will be available soon to Home Institution users.

For more information on the SRW and Home Institution contract options, please visit the Restricted-Use Contract Options page.

A recent study using nationally representative data from Waves IV and V of the National Longitudinal Study of Adolescent to Adult Health (Add Health) examines the effects of long-term exposure to two widely cited pollutants, ozone (O₃) and particulate matter 2.5 (PM₂.₅), on allergy and asthma diagnoses in adolescents and young adults. Ozone and particulate matter were measured using annual average concentrations generated from the EPA’s Fused Air Quality Surface using Downscaling (FAQSD) data and assigned to participants based on their tract of residence in each wave. Health outcomes were measured using self-reported survey questions asking whether the participant’s child had ever been diagnosed with asthma or allergies, with relevant covariates included in the analysis.

The study focused on 6,860 children between the ages of 10 and 25 of the original Add Health participants from Waves IV and V. Findings showed that exposure to ozone and particulate matter was associated with a higher likelihood of asthma in females aged 10 to 12 and a higher likelihood of allergies in males aged 13 and above. This study shows that air pollution can have varying health impacts, dependent upon timing and demographics, which emphasizes that environmental regulations and interventions must account for both age and sex.

To read the full article click the link below. For more important findings using Add Health data, visit the Add Health publications page.

Amialchuk, Aliaksandr, and Onur Sapci. “The Effect of Long-Term Exposure to O3 and PM2.5 on Allergies and Asthma in Adolescents and Young Adults.” International Journal of Environmental Research and Public Health, vol. 22, no. 8, Aug. 2025, p. 1262.  doi:10.3390/ijerph22081262.

There is a large pool of research focusing on how adolescents’ perceptions of survival predict important aspects of their young adult lives, especially their physical and mental health, risky behaviors, and socioeconomic status. Using nationally representative data from Wave I of the National Longitudinal Study of Adolescent to Adult Health (Add Health), Carlyn Graham et. al. investigated whether those perceptions extend beyond these aspects to actually predict premature mortality, controlling for demographic, socioeconomic, health, and behavioral factors. Perceived survival expectations were measured using a single Wave I survey question asking, “What do you think are the chances you will live to age 35?” Responses ranged from “almost no chance” to “almost certain” and were categorized into three groups: “50% chance or less,” “a good chance,” and “almost certain.” The outcome, all-cause mortality (measured binarily as alive or deceased), was tracked from Wave I (1994–95) through December 2021 using the Mortality Outcomes Surveillance Data files.

The study included 18,923 participants and findings showed that when adjusting for sex and race, adolescents who perceived a 50% chance or less of surviving to age 35 had a higher risk of mortality compared to those who were almost certain they would survive. The strength of this association was weakened after sequentially adjusting for socioeconomic status, physical and mental health, risky behaviors, and exposure to violence. When separating analysis by sex, lower perceived survival was strongly associated with higher premature mortality risk among female adolescents, but not males. This study highlights the importance of addressing adolescents’ survival perceptions, emphasizing that healthcare providers should pay special attention to females’ sense of risk at a young age.

To read the full article click the link below. For more important findings using Add Health data, visit the Add Health publications page.

Graham, Carlyn, Robert A. Hummer, and Carolyn T. Halpern. 2025. “Gazing into the Crystal Ball: Do Adolescent Survival Expectations Predict Premature Mortality Risk in the United States?” Social Science & Medicine 364:117548. doi:10.1016/j.socscimed.2024.117548.

Add Health is excited to announce the following data are now available:

Wave VI Anthropometrics

Wave VI Cardiovascular Measures

Wave VI Demographics Home Exam

Wave VI Glucose Homeostasis

Wave VI Hepatic Injury

Wave VI Lipids

Wave VI Medications Home Exam

Current Add Health investigators can log in to the CPC Data Portal and use the “Request More Data” button to order these datasets.

For more information on the CPC Data Portal, please visit the Frequently Asked Questions page. 

The following Add CAPS data are now available:

Animal Naming Test

This test provides data on a participant’s verbal fluency/language by assessing their ability to generate words within a semantic category under time constraints. Participants are asked to name as many animals as possible within a fixed time period. The primary research outcome for this test is the total number of unique, valid animal names produced within 60 seconds. N=2,613, 20 variables

Physical Function

Handgrip strength is a reflection of the overall state of muscle strength and physical function. These test results serve as a practical indicator of age-related functional decline. N=2,613, 28 variables

Sensory Function

The Sensory Function dataset provides data on participants’ auditory functioning, assessed using the hearX hearTest mobile audiometry system. This assessment measures hearing thresholds across multiple frequencies in both ears to evaluate hearing sensitivity and identify potential hearing impairment. The primary research outcomes include pure-tone averages (PTA) for each ear. N=2,613, 49 variables

NIH Toolbox Cognition

The NIH Toolbox Cognition battery includes three cognitive assessments: Dimensional Change Card Sort Test, Pattern Comparison Processing Speed Test, and a Picture Vocabulary Test. These tests provide data on the cognitive domains of executive function, language, and processing speed. N=2,613, 55 variables

Word Recall and Backward Digit Span

The Word Recall tasks were included in the Add CAPS battery to assess episodic memory, a cognitive domain that is known to decline with age and is predictive of dementia risk. Backward Digit Span provides a measure of working memory, reflecting the ability to temporarily hold and manipulate information. Results from these assessments can be combined with results from the same tests in Waves IV and V to conduct longitudinal analyses of cognitive function. Both tasks were adapted from standard neurocognitive batteries. N=2,613, 72 variables

To access the Wave VI restricted-use data, please visit the Add Health Data Portal.

Add Health is pleased to announce the following Wave VI Restricted-Use Data are now available:

• Wave VI Mixed-Mode Survey (Samples 1 and 2)
• Wave VI Mixed-Mode Survey (Sample 2)
• Wave VI AddCAPS – Test My Brain
• Wave VI Survey Medications 
• Wave VI Final Disposition of Initially Eligible Cases
• Wave VI Mixed-Mode Survey Weights

Please visit the Add Health Data Portal to access the Wave VI restricted-use data. As a reminder, researchers must have one of two contract options to access Wave VI data.

1. Secure Research Workspace (SRW) Contract: This option provides access to Add Health data through the University of North Carolina’s Secure Research Workspace (SRW).

2. Home Institution Contract: This option to access Add Health data requires the Principal Investigator’s home institution to deploy a secure server that complies with federal data security standards and is managed by the institution’s IT unit.

Comprehensive information on both access options may be found on the Restricted-Use Contract Options page.

The new Contracts Management System (CMS) is now available. Any researcher interested in applying for a new restricted-use contract or renewing their existing contract may access the CMS via the Add Health Data Portal. 

Researchers now have two options for accessing Add Health restricted-use data:

1. Secure Research Workspace (SRW) Contract: This option provides access to Add Health data through the University of North Carolina’s Secure Research Workspace (SRW).

2. Home Institution Contract: This option to access Add Health data requires the Principal Investigator’s home institution to deploy a secure server that complies with federal data security standards and is managed by the institution’s IT unit. 

The CMS is designed to facilitate an online process for the application, renewal, and administration of restricted-use data agreements, thereby enhancing efficiency and user experience. Anyone who is currently working on the SRW does not need to do anything at this time.

With the release of Wave VI data, the UNC Data Portal will no longer support Add Health data downloads. This change applies to requests for both newly released and previously available datasets. As a reminder, researchers must have one of two contract options to access Wave VI data when it is released. Comprehensive information on both access options is available on the Add Health Restricted-Use Data page.

Most U.S. Alzheimer’s disease (AD) research focuses on older adults, leaving little understanding of risk factors earlier in life across representative populations. Using nationally representative data from Waves IV and V of the National Longitudinal Study of Adolescent to Adult Health (Add Health), researchers investigated whether widely cited AD risk factors and blood biomarkers are associated with cognitive function before midlife. Risk factors were assessed using the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) Score, a comprehensive algorithm integrating social, behavioral, and biological factors such as education, sex, age, cholesterol, blood pressure, body mass index, and physical activity. Biomarkers included APOE ε4 status, two neuropathological ATN markers (total Tau and neurofilament light chain [NfL]), and several inflammatory molecules and interleukins, including high-sensitivity C-reactive protein (hsCRP), IL-1β, IL-6, IL-8, IL-10, and TNF-α. Cognitive function was assessed using three tests: immediate word recall, delayed word recall and backward digit span.

The study included 4,507–11,449 participants in Wave IV (median age 28) and 529–1,121 in Wave V (median age 38). Roughly half were women, and most were White, with smaller proportions of Black and Hispanic participants. Findings showed that higher CAIDE scores were linked to lower performance on all three cognitive tests in Wave IV. In Wave V, higher levels of total Tau were linked to worse immediate word recall results. In both Wave IV and V, blood markers of inflammation (such as hsCRP, IL-6, IL-1β, IL-8, and IL-10) were also linked to lower cognitive scores across all tests. This study shows that known Alzheimer’s risk factors are linked to cognitive function in adults aged 24–44, not just older populations, emphasizing that prevention efforts in the U.S. should begin earlier.

To read the full article, please click the link below. For more important findings using Add Health data, visit the Add Health publications page.

Risk factors for Alzheimer’s disease and cognitive function before middle age in a U.S. representative population-based study. Aiello, Allison E. et al.The Lancet Regional Health – Americas, Volume 45, 101087