Nurses' Health Study
The Nurses' Health Study (abbreviated NHS) is a U.S. longitudinal study that yielded important contributions to food science and cancer risk in women. Since 1976 there are the two annual surveys and partly clinical studies of thousands of nurses.
It is the world's most important health longitudinal study that has been running for 30 years.
The English name of the study has no generally recognized German translation has been found. It expresses the composition and the main issue, namely the health of female carers. Sometimes the term Womans Health is used for the study.
First focus of the study was the question of the effect of birth control pills on breast cancer risk.
Due to the size of the participants circle numerous epidemiological data are now available. Recurring themes of the evaluations are nutrition and various cancer risks, particularly the risk of breast cancer but also cardiovascular disease and cognitive function among older women.
- 2.1 stroke and vegetables
- 2.2 Dietary fiber and colorectal cancer
- 2.3 vegetables and fruits and cardiovascular disease
Study design of the two cohorts
Meanwhile, two cohorts differed ( composition of participants):
Cohort 1 in 1976: Approx. 122,000 35 - to 55 - year-old married nurses ( 170,000 had been written ) of 11 populous states.
1980, the first questionnaire on dietary habits was used. After this every four years have been collected, the demographic and other health data in two yearly intervals. The response rate here was about 90%. This showed that the basic assumption, nurses were good to motivate them to participate in the follow-up appointments and re-investigations, was correct. 33,000 blood samples were collected from 1989 to 1990.
Cohort 2 from 1989: In particular, women were included who had already taken the pill as a teenager. Approximately 117,000 25 - to 42 - year-old married nurses ( 125,000 had been sought as a target on the first letter to 517,000 answered approximately 123,000, 24 %. ). After exclusion of incomplete questionnaires were 116 686 participants in this cohort ( Nurses' Health Study II). Again, about 30,000 blood samples were collected in the 1990s and to participate in the re-investigations in each case was about 90%. Due to the large number of ( non-participation in follow-up appointments ) with long course of study is still secured the statistical representativeness of the results, even with the usual drop outs.
Participating individuals and institutions
The two doctors Frank E. Speizer, and Walter C. Willett are considered the founders.
Participating institutions are the Harvard Medical School, Harvard School of Public Health, Brigham and Women 's Hospital, Dana -Farber Cancer Institute, Children's Hospital Boston, Beth Israel Deaconess Medical Center and the Channing Laboratory.
Was funded study by the National Institutes of Health, an agency of the U.S. Department of Health.
Examples of questions, results
The following examples of issues, results or partial results from the study should be interpreted cautiously. The English " findings " describes the results.
Based on which attendance numbers it came to testify? What was this in the original ( because unverified quotes often " sensationalist " shorten )? Name the research group relationships or a cause - effect relationship?
Stroke and vegetables
In the study, were observed in the 75 596 nurses for 14 years, showed that in the consumption of vegetables, especially green leafy vegetables and citrus fruits and their juices, rarely occurred a stroke.
Dietary fiber and colorectal cancer
The fiber - thesis of many nutritionists claims: dietary fiber protect against colon cancer. This thesis has not yet been proven. Also Nurses' Health with 76 947 over 16 years observed nurses showed no clear relationship between fiber intake and colorectal cancer.
Fruit and vegetables and cardiovascular disease
On 2 November 2004, the news agency CNN issued a statement that data from large epidemiological studies Nurses' Health Study and Health Professionals Follow -up Study showed that a high intake of fruits and vegetables - such as vegetarians usual - a statistically significant, small protective effect against cardiovascular diseases caused. In the Nurses' Health Study, 71,910 nurses were studied and the Health Professionals Follow -up Study 37 725 male doctors.