Nurses' Health Study
The Nurses' Health Study (NHS) is considered the "grandmother" of women's health studies and represents the single largest cohort study of women, which has resulted in more than 265 published scientific papers. The NHS was established in 1976 to study the relationship between the use of oral contraceptives and cigarette smoking and the risk of major illnesses. For a variety of reasons, including the dedication and commitment of the participants, the scope and range of the study has broadened over time to evaluate the implications of various lifestyle factors such as exercise and diet on women's health.
The study was comprised of data from 127,000 nurses between the ages of 30 and 55. Participants receive detailed questionnaires every 2 years in which they report medical histories, daily diet habits and major life events that have occurred in the past 24 months.
The response rate averages 90 percent, and the data compiled from the study is now equivalent to more than 600,000 typed pages.
Some of the major findings of the Nurses' Health Study include:
- Birth control pills do not increase non-smoking women's risk of heart disease.
- Women who take oral contraceptives for more than 5 years have less than half the risk of ovarian cancer than women who have never used birth control pills.
- Women who take estrogen after menopause decrease their risk of heart disease, but raise their risk of developing breast cancer.
- Increased dietary calcium intake among post-menopausal women is not protective against fractures of the hip and wrist, although a positive relationship was observed between protein intake and risk of fractures.
- A diet rich in red meat raises the risk of colon cancer.
- Women who drink moderate amounts of alcohol (1-3 drinks per week) cut their risk of heart attack in half, but increase their risk of breast cancer by one third.
- Limiting fat intake and eating more high fiber foods does not reduce a woman's risk of breast cancer.
- Women who have taken multi-vitamin supplements that contain folic acid have a 75 percent reduced risk of colon cancer.
Send Feedback to: 
