This protocol was placed on hold in January 2023 as funding was not received to support study activities and recruitment was never initiated. This protocol will be fully closed as new projects are underway that support similar outcome measures.

This study is being done to evaluate heart rate activity and sleep patterns, among participants in the Long-Term Follow-Up (LTFU) study.

Primary Objective

Using mobile health (mHealth) technologies in a large and well-characterized cohort of childhood cancer survivors, our primary objective is to understand the magnitude of increased risk of cardiac autonomic dysfunction by (a) comparing prevalence rates among survivors and siblings, and (b) determining the prevalence within specific subgroups of childhood cancer survivors defined by race, sex, cancer type and treatment exposures, and type and severity of chronic health conditions.

Secondary Objectives

Among long-term (≥5 years) survivors of childhood cancer (a) identify demographic, disease, treatment and cognitive-behavioral factors associated with an increased risk of cardiac autonomic dysfunction, (b) develop and validate risk prediction models for future clinical use in identifying individuals who may benefit from targeted interventions, and (c) investigate associations between dysfunction and perceived well-being.

Potential participants will be recruited by email and phone. Survivors who wish to participate will complete an online consent form and then a series of short questionnaires to determine study eligibility. This data collection will take place in DatStat Connect, which is the online consenting and data collection tool utilized for the CCSS. Consented/enrolled SJLIFE participants will receive a link via email to complete surveys related to autonomic functioning and current medical concerns and asked to schedule delivery of a WHOOP® strap prior kit prior to scheduling a device setup session with a team member. The kit will include the WHOOP® strap, brief instructions for setup, and prepaid return mailing materials. The WHOOP® strap will be shipped to the participant and each participant will complete a training session and app installation, if needed, and instructions regarding during of wear (two weeks)

Inclusion Criteria:

• Enrollment on the CCSS protocol.
• 18 years or older.
• Has a smartphone and is willing to download the WHOOP® app for the duration of study participation.
• Reports no history of allergic reaction (e.g., rash) to fitness monitoring wearables.

Exclusion Criteria:

• Unable to independently provide informed consent.
• Visual impairment that prevents participant from engaging with study materials.
• Unable to read or understand study materials in English.
• Mailing address outside the United States.

Those who meet the eligibility criteria