The Women's Health Initiative (WHI) is a long-term national health study that has focused on strategies for preventing the major causes of death, disability, and frailty in older women, specifically heart disease, cancer, and osteoporotic fractures.
Hormone Therapy Trials (HT): This component examined the effects of
combined hormones or estrogen alone on the prevention of heart disease and
osteoporotic fractures, and associated risk for breast cancer. Women
participating in this component took hormone pills or a placebo (inactive pill)
until the Estrogen plus Progestin and Estrogen Alone trials were stopped early
in July 2002 and March 2004, respectively. All HT participants continued to be
followed without intervention until close-out.
Dietary Modification Trial (DM): The Dietary Modification component evaluated the effect of a low-fat and high fruit, vegetable and grain diet on the prevention of breast and colorectal cancers and heart disease. Study participants followed either their usual eating pattern or a low-fat dietary pattern.
Calcium/Vitamin D Trial (CaD): This component evaluated the effect of calcium and vitamin D supplementation on the prevention of osteoporotic fractures and colorectal cancer. Women in this component took calcium and vitamin D pills or placebos.
WHI Extension Studies continued follow-up of consenting participants, the first consenting participants from each of the original WHI study components for an additional five years (2005-2010) of follow-up, and the second consenting participants from the first Extension Study for an additional five years (2010-2015). In 2015, WHI was awarded additional funding to continue follow-up of participants through 2020. Annual updates on health outcomes are collected by mail from the participants enrolled in each Extension Study. See WHI Timeline for WHI and the Extension Studies.
The following sections describe the study's design, procedures, and components:
Design and Protocol - Design of the WHI Clinical Trial and Observational Study.
Recruitment - Specifics about recruitment methods.
Screening and Enrollment - Eligibility, screening, enrollment, and randomization.
Retention & adherence - Retention strategies and adherence monitoring.
Data collection procedures - Clinical measurements and data collection forms.
Biospecimen collection - Blood collection, storage, and analytes.
Outcomes - Clinical outcomes, ascertainment, and adjudication.
Hormone Therapy Trials - Overview, intervention, follow-up, and findings.
Dietary Modification Trial - Overview, intervention, follow-up, and findings.
Calcium and Vitamin D Trial - Overview, intervention, follow-up, and findings.
Observational Study - Overview, intervention, follow-up, and findings.
WHI Findings - Where to find publications and summaries about WHI findings.
WHI Extension Study (2005-2010) - Overview of extended follow-up of consenting participants, 2005 - 2010.
WHI Extension Study (2010-2015) - Overview of extended follow-up of consenting participants, 2010 - 2015.
Long Life Study, including OPACH
Rossouw J, Anderson G, Oberman A. Baseline Monograph - Foreword. Ann Epidemiol 2003;13:S1-S4.