Women with Gestational Diabetes Mellitus (GDM) are 12-times more likely to develop Type 2 Diabetes (T2D) 4-6 years after delivery than women without GDM. There has been evidence that lifestyle modifications such as physical activity (PA), dietary intake, sleep, and stress management can prevent or delay type 2 diabetes (T2D). The purpose of this study is to assess the efficacy of a holistic lifestyle digital health intervention with post-GDM women in large community settings in Singapore. The study consists of a 1-year randomized controlled trial (RCT) with 3 years follow-up. Women who are eligible for the study will be randomized to either Group 1 (Intervention) or Group 2 (Control) at baseline. Both groups will be followed in years 2-4. Women from both groups will be provided with an Oura ring for tracking physical activity, sleep, and heart rate variability (a proxy for stress), and the "HAPPY app," which will provide health promotion information about physical activity, diet, sleep, and mental wellbeing, as well as display the information collected (such as body mass index, blood pressure, and OGTT results). The active group will receive the "LVL UP app" a smartphone-based chatbot-delivered intervention, designed to provide personalized recommendations through multiple digital coaching sessions aimed at improving health literacy and practicing healthy lifestyles to prevent Type 2 diabetes and common mental disorders (i.e., anxiety, depression).

The overall goal of this study is to reduce the risk of Type 2 diabetes (T2D) and pre-diabetes in Asian women and their children by focusing upon a major high-risk group - women with a history of gestational diabetes (GDM) in Singapore. GDM is diabetes diagnosed for the first-time during pregnancy and has traditionally been considered a benign condition because typically glucose levels return to normal after delivery. Women with pregnancies complicated by GDM often progress to develop T2D later in life.

There is evidence that holistic lifestyle modifications that include strategies to improve dietary intake, physical activity, and mental well-being can prevent or delay the onset of type 2 diabetes. The use of digital health interventions can also assist in the prevention of T2D. However, limited studies have been conducted with Asian populations.

This study aims (1) to identify post-GDM women from large community settings in Singapore and to assess the efficacy of a holistic lifestyle digital intervention (focusing on diet, physical activity, sleep, and mental well-being) on glucose regulation with those identified women.

Secondary objectives are: (a) to examine the potential impacts of the proposed intervention on the health and well-being of subjects' family members (e.g., children); (b) to determine the diabetes risk of the subjects over a 3-year follow-up period; (c) to explore potential economic impacts of the proposed intervention (e.g., healthcare expenditures); (d) to study the importance of gut microbiota and epigenetic factors in relation to changes in glucose metabolism, and (e) to ascertain the safety of the proposed intervention.

The study is a 1-year randomized controlled trial with three years of follow-up. The primary outcomes involved the incidence of Type 2 diabetes confirmed by a 2-hr 75g Oral Glucose Tolerance Test (OGTT) over a 4-year period. Secondary outcomes are (1) incidence of impaired fasting glucose and impaired glucose tolerance; (b) changes in cardiometabolic variables (e.g., body weight, HbA1c, insulin, blood lipids, blood pressures) in the women; (c) changes in women's body composition; (d) changes in women's mental well-being (e.g., defined by BDI-II, STAI, WHO-5, PSS-4); (e) changes in the health and wellbeing of their children, and (f) a composite of major adverse events (MAE) comprising fatal and non-fatal events associated with Type 2 diabetes.

Eligible women will be randomized at baseline to either Group 1 (Intervention) or Group 2 (Control) for 1 year.

Group 1 (Intervention) consists of several virtual coaching sessions about healthy lifestyle delivered by a conversational agent (chatbot) embedded in the LvL UP App within 24 weeks (weeks 2 to 26) to complete three levels of health literacy. Additionally, individuals will receive an Oura ring at baseline (activity-tracking wearable that collects lifestyle data), as well as the HAPPY App (educational content about lifestyle and health outcomes [e.g., body mass index, blood pressure, OGTT results]).

Group 2 (Control) subjects will receive an Oura ring at baseline, and the HAPPY App

Follow-up Period Upon completion of the one-year RCT period, both groups will be followed-up for 3 years. During the follow-up visits, body measurements, OGTT, bio-sampling, and data collection will be conducted.

Both groups will be assessed at baseline, week 26, 1 year visit, 2-year visit (follow-up 1), 3-year visit (follow-up 2), and 4-year visit (follow-up 3)

Inclusion Criteria:

1. Female, age: 21 - 45 years
2. Had a history of GDM (at least 1 year and not more than 10 years)
3. Chinese, Malay or Indian ethnic groups
4. Body mass index (at least 18.5 kg/m2 and not more than 35 kg/m2)
5. Not planning to conceive in the next one year
6. Not performing exclusive breastfeeding during study period
7. Own a smartphone compatible with the study mobile Apps
8. Proficient in English language
9. Plan to stay in Singapore for the next 4 years
10. Willing to comply to study protocol
11. Able to provide a written informed consent

Exclusion Criteria:

1. Current or previous diagnosis of diabetes (Type 1 or 2), except GDM
2. Currently pregnant
3. Given birth within the last 12 weeks
4. Severely limited mobility (e.g., wheelchair bound, require long-term walking aid, etc.)
5. Diagnosed with malnutrition or eating disorder
6. Diagnosed with cancers, unstable heart diseases, severe kidney diseases, severe liver diseases
7. Diagnosed with severe insomnia, unstable mental conditions, dementia, or cognitive impairment
8. Experienced alcohol or drug abuse
9. Currently having medications known to influence glucose metabolism (e.g. peroral corticosteroids)
10. Currently participating in concurrent clinical trial or lifestyle intervention study