Diabetes Prevention Through Genetics, Familial History and Behavior Change

Legacy-DPP: Diabetes Prevention Through Genetics, Familial History and Behavior Change A Family-Enhanced, Genetically-Informed Diabetes Prevention Program

The goal of this clinical trial is to learn if adding a family engagement component to the standard Diabetes Prevention Program (DPP) improves outcomes for adults with prediabetes. It will also learn about the effects of this approach on family members' health.

The main questions it aims to answer are:

• Does adding family health history collection and family participation to the DPP improve session attendance compared to standard DPP?
• Does this family-centered approach lead to greater weight loss and HbA1c (blood sugar) reduction compared to standard DPP?
• Do health improvements extend to participants' family members, and what factors explain differences in family-level outcomes?

Researchers will compare an adapted DPP with a family component to the standard DPP (individual-focused) to see if involving family members improves diabetes prevention outcomes.

Participants will:

• Be assigned to one of two groups: adapted DPP with family sessions, or standard DPP
• If assigned to the adapted DPP, complete a family health history using the CDC's My Family Health Portrait tool and attend 6 additional sessions with family members focused on personalized risk communication
• Attend regular checkups to measure weight and HbA1c at 6 and 12 months
• Have session attendance tracked throughout the program
• Family members of participants may also be asked to complete health assessments to measure any changes in their own health behaviors

Type 2 diabetes affects 38.4 million U.S. adults, and an additional 97.6 million adults have prediabetes and are at risk of developing the disease. This burden falls disproportionately on racial and ethnic minority families and rural communities.

This clinical trial aims to determine whether embedding family engagement and family health history into the Diabetes Prevention Program (DPP) improves adherence, weight loss, and glycemic outcomes among adults with prediabetes, compared to the standard individual-focused DPP.

Participants will be 200 index participants with prediabetes, along with their family members, recruited from rural and urban sites and stratified by geographic location. Index participants will be block randomized to receive either standard DPP or an adapted version that adds 6 weeks of family health history and genetics education-using the CDC's My Family Health Portrait tool-paired with family participation and skill-building sessions.

All participants will attend regular clinic visits to monitor weight and HbA1c at 6 and 12 months and will have session attendance tracked throughout. Family members will also complete health assessments to measure whether health improvements extend beyond the index participant, and researchers will use the Actor-Partner Interdependence Model to identify factors explaining variation in family-level outcomes.

This is a 2-arm randomized controlled trial comparing standard DPP to a family-adapted DPP incorporating family health history, genetics education, and family skill-building.

Inclusion Criteria:

• Age ≥18 years.
• Fasting HbA1c 5.7-6.4% confirmed by CLIA-waived point-of-care testing.
• BMI ≥25 kg/m².
• Able to provide informed consent.
• Has an adult household/family or framily (fictive kin) member willing to enroll as a paired participant.
• Willing to attend in-person sessions

Exclusion Criteria:

• Minors <18 years
• Prior diagnosis of T1 or T2D.
• HbA1c ≥6.5% at screening (Aim 1/2 curriculum eligibility)
• Current glucose-lowering medication use
• Pregnancy
• Physical-activity contraindications
• Individuals unable to speak or understand English