Data Resource Profile: Self-reported data in the Million Veteran Program: survey development and insights from the first 850 736 participants

Data resource basics

Health surveys have been used for many years as a tool for determining risk factors and disease occurrence in populations.¹ Self-reported investigations enable researchers to collect information on a population’s medical, social, economic and lifestyle history which often affect their health. Large-scale studies that use surveys such as the National Health and Nutrition Examination Survey, the National Institutes of Health All of Us and UK Biobank have markedly contributed to biomedical knowledge through survey-based capture of exposures and outcomes. As the field of precision medicine continues to expand, survey data augmented with electronic health record (EHR) and genetic data can also provide invaluable information on social and lifestyle determinants of health which influence the variability of an individual’s genes and risk for disease, treatment and prevention.²

The Department of Veterans Affairs (VA) has a long-established history of using data from the VA’s EHR system for research, but studies have often centred on a specific exposure, disease outcome or service era. Additionally, studies using survey data have often been limited in sample size or are not representative of the entire Veteran population. To expand the scope of research to improve Veteran health, the VA’s Office of Research and Development (ORD) launched the Million Veteran Program (MVP) in 2011 to create a VA-based infrastructure resource for genomic data collection among Veterans.³ As part of the programme’s efforts, surveys were designed to collect individual participant information to enhance the use of MVP genomic data for clinical research. Currently there is no source of large-scale, self-reported health and lifestyle data which exist within VA data sources such as the Corporate Data Warehouse (Health Data Repository), the National Patient Care Database, VA-Medicare merge, national Laboratory and Pharmacy extracts and the VA Vital Status File.

MVP methodology has been previously described.³ Briefly, enrollment of users of the Veterans Health Administration (VHA) began in 2011 with the goal of enrolling at least 1 million Veterans. The MVP Baseline Survey is included as part of initial mailed invitational materials; therefore participants may complete the MVP Baseline Survey prior to or following enrollment in MVP. Participation in MVP involves: (i) collection of self-reported data; (ii) provision of blood specimens for genetic research; (iii) access to health records on an ongoing basis; and (iv) agreement for additional research opportunities. Once a Veteran enrols in MVP, the MVP Lifestyle Survey is available for completion and is mailed typically within 2–4 weeks following enrollment. To date, participants have been primarily recruited through mailings and in-person enrollment at VA MVP facilities or events. In 2019, MVP launched MVP Online, an electronic portal whereby Veterans can enroll in MVP, complete surveys and schedule specimen collection activities.

Data collected

MVP survey development

Development of the MVP surveys involved extensive review of existing large-scale cohort data collection instruments, evaluation of available data within the VHA EHR and identification of key topics specific to Veteran health and wellbeing. The selected key health risk factors and measures are listed in Table 1. Pilot work was conducted in advance of MVP’s launch, to determine survey length tolerability, optimal method of administration (in-person or self-administration) and timing of completion (pre-/post-enrollment). Various survey versions were created and administered through the mail or in person. By using multiple data capture methods (self-administered vs in-person interview or a combination), the pilot work also helped determine the best method of data capture to maximize enrollment and minimize participant burden. Ultimately, the efficiency of the survey data was determined to be best collected through participant completion in their own time. This was especially important for questions related to family pedigree and health, to allow for consultation with family members and/or records as needed.

Based on the pilot work, two surveys were developed as part of enrollment in MVP (Table 1). The MVP Baseline Survey focuses on participant demographics, medical history, family history, military experience and selected lifestyle factors. The MVP Lifestyle Survey focuses on daily/lifestyle habits (such as physical activity, smoking, diet), environmental exposures, gender-specific health and topics specific to Veteran health including combat experience, environmental exposures during military service and post-traumatic stress disorder. The final survey domains and sources are presented in Table 1. Completion time for the MVP Baseline Survey is approximately 15–20 min and 45 min for the MVP Lifestyle Survey.

Survey data quality and management

Completed MVP surveys are scanned and digitally archived. Responses to survey questions are processed through a third party vendor who captures and validates data electronically. Indeterminate and write-in values are flagged for later resolution. Given the large number of surveys, data review and cleaning by the vendor are limited to resolving invalid multiple responses by choosing the most conservative response and restricting free response values within a plausible range. Any changes to the original data are flagged to indicate that cleaning was completed on a variable. Ongoing cohort maintenance is managed routinely by the MVP Data Analytics Team who review electronic survey data from newly enrolled MVP participants and apply cleaning macros so that new data are consistently formatted and processed.

Survey data collected

As of 20 September 2021, 6 365 863 participants have been invited to participate in MVP and 850 736 participants have enrolled, with a response rate of 13.36%. Among enrollees, 593 141 (69.72%) enrolled by ‘walk-ins’ at a study site, 246 293 (28.95%) enrolled at a scheduled appointment and 11 302 (1.33%) enrolled online. Among the enrolled participants, 513 306 have completed the MVP Baseline Survey (91.54% male and 8.46% female). In total, 389 287 participants have completed the MVP Lifestyle Survey (91.92% male and 8.08% female), of whom 345 312 have also completed the MVP Baseline Survey (Figure 1).

Briefly, the MVP Baseline Survey includes eight sections with 54 items. As shown in Table 2, the majority of participants enrolled between 2012 and 2017. The enrollment rate decreased in 2020 and 2021 as a result of the COVID-19 pandemic; 79% of males were aged 50–80 and 91% of females were aged younger than 70 years. Black participants accounted for 12.48% of males and 21.08% of females; educational level of 63.01% females and 42.2% males were college or above. Table 2 also briefly presents the number of responders and average levels of physical features, uniformed services experience, activities, habits, health status, lifetime health conditions, health care usage and two samples family history (family histories of 19 diseases were included in the survey). Besides these items presented in Table 2, the Baseline Survey also collected detailed information on 75 health conditions including ‘the year of diagnosis’ and ‘whether taking medications’ for each condition.

The MVP Lifestyle Survey includes 10 sections consisting of 70 items. Several items present a series of questions that are based on standardized questionnaires (Table 3) including insomnia disorders,^4,5 physical activity pattern,^6,7 Mental Disorders Screening Scores of Generalized Anxiety Disorder 2-item (GAD-2) and the 2-item Patient Health Questionnaire (PHQ_2)^8,–9 for anxiety and depression, Medical Outcomes Survey (MOS) for Cognitive Functioning,¹⁰ MOS Social Supports,¹¹ posttraumatic stress disorder (PTSD) Checklist—Civilian Version,¹² Combat Experiences Scale from the Deployment Risk and Resilience Inventory,^13,14 and adapted Structured Neurotoxicant Assessment Checklist.¹⁵ Besides these primary results, the data collected by the Lifestyle Survey would be further developed and adapted to use in other ways. For example, the frequency of physical activities at different intensities could be converted into average metabolic equivalent for task (MET) values of the overall activity level¹⁶ and the frequency of food intakes could be converted to dietary energy and nutrient intakes in combination with the data of food composition table.

Extended data capture

A hallmark feature of MVP involves the ability for ongoing data capture from enrollees. As MVP continues to evolve, re-contact of enrollees is anticipated to expand to multiple modalities, such as wearables and Integrated Voice Recognition (IVR). Additionally, with the launch of MVP Online, to date over 20 000 Baseline and Lifestyle Surveys have been completed electronically. Online survey completion allows for cleaner data collection (as a result of built-in validation checks and single option choices for appropriate questions) and also tailored survey workflows so that participants are presented with only the applicable items.

Data resource use

The self-reported data collected from MVP surveys are an invaluable resource for Veteran research. MVP Baseline and Lifestyle Surveys were designed to capture participant self-reported information on demographics, family history of disease, health status, nutrition and lifestyle factors that can influence or be influenced by genetic predisposition, which is critical for understanding gene-environment interactions, nutrigenomic associations and the impact of personal factors on genome-disease associations. Given the large sample size, MVP Baseline and Lifestyle Survey data can be used independently to examine Veteran health and behavioural outcomes or in conjunction with electronic health records (EHR) and genomic data to improve our understanding of Veteran health. EHR provide valuable longitudinal data for researchers and health care providers to track the disease progression of a patient over time, but EHR alone do not provide sufficient information for investigating how health is affected by behaviour and environmental factors. Data from the MVP Baseline and Lifestyle Surveys bridges this gap by providing detailed behaviour and environmental information that is consistently captured across a large sample of Veterans. For greater applicability, it is envisioned that the MVP Baseline and MVP Lifestyle Surveys will be validated in future MVP scientific projects to enhance the understanding of Veteran health and wellbeing. MVP participants represent a wide range of ancestry and ethnic backgrounds, including Hispanic, European/European American, African American/Afro-Caribbean, East Asian and others.¹⁷

Preliminary results and key findings

MVP data have been used to learn about a range of health conditions affecting Veterans.¹⁸ Research topics include cancer, mental health, osteoarthritis, cardiovascular diseases, COVID-19, Parkinson’s disease, diabetes, PTSD, gene variation, substance use disorder, Gulf War illness, suicide prevention, informatics, traumatic brain injury (TBI), kidney disease, tinnitus and macular degeneration etc.¹⁸ Research demonstrates that the demographic representation of MVP is similar to the VHA population but it contrasted with the overall National Health and Nutrition Examination Survey US population.¹⁸ In particular, the prevalence of overweight and obese individuals is higher among US Veterans, particularly in MVP.¹⁸ MVP research has also revealed gender differences in programme participation rates, demographic profile, health characteristics and prevalence of health conditions for Veterans in the MVP cohort,¹⁹ highlighting the need for tailoring recruitment efforts to ensure representation of the increasing female Veteran population receiving care through the VHA.

Lifestyle factors play an important role in development and prevention of cardiovascular disease (CVD); a broad range of CVD-related lifestyle factors were replicated in Veterans using MVP data, such as fried food,²⁰ eggs,²¹ alcohol,^22–24 fish,²⁵ nuts,²⁶ chocolate,²⁷ potato,²⁸ yogurt,²⁹ overall dietary score of Dietary Approach to Stop Hypertension³⁰ and physical activities.³¹

Data collected from MVP Baseline and Lifestyle Surveys also provide important information to support MVP genetic research studies^{17,23,32–35} including the genetic study of PTSD, alcohol use behaviours, schizophrenia and bipolar disorder, potential causal effect of PTSD on alcohol use disorder and alcohol consumption; and genetic liability to smoking was a strong risk factor for coronary artery disease, peripheral arterial disease and stroke. Data collected from MVP Baseline and Lifestyle Surveys were also used in the recent study of COVID-19,³⁶ which indicated that greater COVID-19 severity was associated with an older age, higher body mass index and history of respiratory, kidney, bacterial or metabolic comorbidities.

Strengths and weaknesses

Overlapping data from the surveys and information found in the VA EHR provide a unique opportunity to validate, supplement and augment a participant’s medical profile using self-reported information. For example, not all MVP enrollees receive 100% of their care from the VHA, so self-report data can provide valuable information to create a more comprehensive enrollee profile. Additionally, as MVP expands eligibility to Veterans who may not use the VA for health care services, the importance of self-report data becomes imperative as MVP builds the infrastructure to access external health records. A key limitation is that not all MVP participants complete the MVP Baseline and/or MVP Lifestyle Surveys, despite repeated efforts to obtain the self-report data. If available, data from EHR are used to supplement aspects of missing self-report data but do not provide the comprehensive profile obtained from the surveys. Whereas currently collection of the MVP surveys is cross-sectional, efforts are under way to design a repeated assessment approach for longitudinal data capture.

Data resource access

As described in detail in Gaziano’s MVP introduction paper³ and MVP website [https://www.research.va.gov/mvp/], access to MVP data and/or samples is governed by the scope of MVP informed consent and VA policies and requires scientific review by appropriate VA review committees. Data are currently available to VA investigators and other approved partners with plans for expanding to non-VA investigators in the future. Enquiries can be directed to Kelly Cho, PhD, at [[email protected]]. For accessing the resource, a consortium approach is strongly encouraged; collaborators from university affiliates and other organizations working with VA investigators are encouraged [https://www.research.va.gov/MVP/research.cfm].

Ethics approval

This research was conducted according to the guidelines of the Declaration of Helsinki and approved by the Department of Veteran Affairs Central IRB (protocol code MVP001, approved in 2010). Written informed consent has been obtained from the participants in accordance with all VA policies and under the authority of the VA Central IRB.

Data availability

See Data Resource Access, above.

Supplementary data

Supplementary data are available at IJE online.

Author contributions

Manuscript writing: X-M.T.N., S.B.W., Y.L., H-N.A.N., K.H. Analytics and data summary: X-M.T.N., Y.L., R.M.Q., R.J.S., K.C. MVP recruitment and enrollment: S.B.W., H-N.A.N., J.V.V.B., J.D., S.M., R.B.R. Oversight and critical review of manuscript for content and clarity: L.D., J.P.C., P.S.T., J.M.G. All authors have read and agreed to the published version of the manuscript.

Funding

This research is based on data from the VA Million Veteran Program supported by award MVP#000 from the Department of Veterans Affairs. This publication does not represent the views of the Department of Veterans Affairs or the US government. The authors have no financial disclosures.

Acknowledgements

The authors thank the members of the Million Veteran Program Core (individuals are named in the Supplementary file, available as Supplementary data at IJE online), those who have contributed to the Million Veteran Program, and specially the Veteran participants for their generous contributions.

Conflict of interest

None declared.

References

Author notes