Women make up a majority of the older population, spend more years in the disabled state and, make up a substantially larger proportion of the nursing home population than men, and have more vulnerability in terms of need for formal and informal care because of their higher rate of widowhood, especially at the oldest ages, compared to men. Despite these factors, little is known about the ways in which specific major chronic diseases cause physical disability, nor about the factors that lead to worsening or improvement. This understanding is necessary in order to define ways to prevent physical disability or its worsening in older adults.
The Women's Health and Aging Study was designed to break new ground by identifying the opportunities for prevention of disability and frailty progression in older adults.
Participants in the study were selected at random from among women aged 65 and over living in community residences in 12 zip code areas of Baltimore City and County. The initial sample included 5,300 women, stratified by age so as to ensure sufficient numbers in the oldest age groups. A brief screening interview identified approximately 1,400 women who were moderately to severely disabled. Of these, 1,002 agreed to participate in the remainder of the study. These women completed a baseline interview and an examination conducted in their homes by a research nurse that included performance-based measures of disability. Follow-up in-person interviews were conducted with participants every six months for the next three years, and annual telephone interviews for two years after that. Enrollment and longitudinal data collection were conducted between 1992 and 2000.
An important component of the investigation is the determination of the causes of the disability experienced by these women. The study is investigating the role of major chronic diseases in causing disability, including coronary heart disease, congestive heart failure, chronic obstructive pulmonary disease, osteoarthritis of hands, hips and knees, rheumatoid arthritis, hip fracture, stroke, intermittent claudication, diabetes, cancer, Parkinson's Disease, vision and hearing impairment, falls and balance abnormalities, and urinary incontinence. Data from the interviews were supplemented by information abstracted from medical records at hospitals and physicians offices to verify the presence and severity of specific diseases and conditions. A team of clinicians reviewed each case and decided what conditions caused the limitations of functioning. The follow-up information is used to assess the long-term changes in disability and factors that influence the direction and rate of change. In addition, the study assesses the role of cognition and a range of psychosocial factors in modifying the ways in which diseases cause disability.
This investigation represents the next generation of epidemiologic research on older populations. It addresses a need for more detailed, more biomedically oriented research to be done on a smaller, more intensively studied yet representative sample of older women. Supported by Contract No. N01-AG-1-2112 from the National Institute on Aging to the Johns Hopkins University School of Medicine, Baltimore, Maryland.
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