This project examines the feasibility of a smartphone-based intervention to reduce obesity and breast cancer risk among Chinese women in China. The proposed intervention is to use the mobile application and an activity tracker device to promote a healthier lifestyle and physical activity. The intervention will be tailored to the participants' behaviors, personal needs, and preferences. The aim is to reduce abdominal obesity and improve healthy lifestyle behaviors in premenopausal women with children in order to reduce the growing cancer burden in China.

Cancer presents a major disease burden across the globe. The incidence and mortality of gynecologic cancers have increased significantly in China over the last two decades with breast and endometrial cancer as leading causes of death in women in China. Obesity, especially abdominal obesity, and unhealthy lifestyles are major risk factors for breast and endometrial cancer. A high risk group for obesity is mothers with dependent children as they have high levels of stress and family responsibilities that prevent regular engagement in a healthy lifestyle and early screening activities. Because reducing postmenopausal abdominal obesity is very difficult and because of the significant increased risk for gynecologic cancers in obese postmenopausal women, interventions that aim to reduce abdominal obesity and improve healthy lifestyle behaviors in premenopausal women with children are critical to reducing the growing cancer burden in China. A smartphone-based intervention provides a promising platform for obesity and cancer prevention. In this proposed study, the research team will modify the Healthy Mothers Healthy Children: Technology-Based Intervention to Prevent Obesity, which was developed by the principal investigator. The proposed intervention (titled "The Smartphone-Based Cancer and Obesity Prevention Education Program for Chinese Women: SCOPE-Chinese Women") is a smartphone-based, data-driven, and individually tailored intervention. It includes 12 weekly educational modules and six bi-weekly tailored messages delivered via WeChat, a popular communication app in China. The intervention will also be tailored to the participants' behaviors, personal needs, and preferences. The overall goal of this proposed study is to assess the feasibility and estimate the preliminary efficacy of the SCOPE-Chinese Women intervention using a randomized control study design (RCT). The following aims will be addressed.

Aim 1: To assess the feasibility of the smartphone-based lifestyle intervention (i.e., SCOPE-Chinese Women).

Aim 2: To estimate the preliminary efficacy of the SCOPE-Chinese Women intervention on the primary outcome (waist circumference) and secondary outcomes (body mass index, self-efficacy, food intake, physical activity, and metabolic risk) between the intervention and control groups at baseline, 3 months, and 6 months.

Aim 3: To understand participants' acceptance, barriers to adherence, and recommendations for intervention.

Inclusion Criteria:

Participants must:

• Be female
• Be at least 18 years old
• Have a waist circumference great than 80 cm
• Own a smartphone
• Be able to read Chinese and speak Mandarin
• Be premenopausal
• Have a child between the age of 1 and 18 years old

Exclusion Criteria:

Women are excluded from the study if they:

• Are pregnant
• Gave birth less than 12 months prior to enrollment date
• Have an acute or life-threatening disease (e.g., renal failure).

To decrease cross-contamination of treatment effect, the six study sites will be the units of randomization. A Statistical Package for Social Sciences (SPSS) program will be used to statistically match the groups and to randomly assign each study group.