Design and methods of the Apple Women's Health Study: a digital longitudinal cohort study

Area of Science:

• Digital Health
• Women's Health Research
• Longitudinal Cohort Studies

Background:

• Limited prospective longitudinal cohorts exist for women's health and gynecologic conditions.
• The Apple Women's Health Study addresses this gap by examining menstrual cycles, health, and behavior.

Purpose of the Study:

• To describe the design and methods of the Apple Women's Health Study.
• To present the demographic characteristics of the initial 10,000 participants.

Main Methods:

• Mobile-application-based longitudinal cohort study utilizing survey and sensor data.
• 10,000 participants enrolled via the Apple Research app between November 2019 and May 2020.
• Monthly follow-up surveys and optional sensor-based data collection via Apple Watch and HealthKit.

Main Results:

• The initial cohort (N=10,000) was diverse in race, ethnicity, and education, predominantly using iPhones.
• 72% used Apple Watch; 24.4% consented to sensor data collection.
• Menstrual cycle tracking via HealthKit was high (82.7% overall), with an average tracking duration of 4.44 months.

Conclusions:

• The Apple Women's Health Study successfully recruited a diverse cohort using a mobile platform.
• High-dimensional data from this cohort can advance understanding of women's health and population trends.
• Strategies to improve survey response rates are crucial for future retention and data quality.