The Nurses’ Health Study

The Study

The Nurses’ Health Study began in 1976 with 121,700 female registered nurses and has followed participants for decades. Researchers repeatedly collected information about health, lifestyle, medications, and newly diagnosed diseases, and detailed dietary questionnaires were added in 1980.

Links to This Study

• Official Nurses’ Health Study history
  The study’s official history page explains how the original cohort was established, how participants have been followed, and how the research focus expanded over time.
• Selected Nurses’ Health Study publications
  The official study website provides selected scientific papers produced from the Nurses’ Health Studies.

How Did the Study Begin?

In 1976, researchers enrolled 121,700 female registered nurses who were 30 to 55 years old. The participants were followed repeatedly over time rather than studied only once.

How Were the Women Followed?

Researchers collected updated information about health, lifestyle, medications, and newly diagnosed diseases. Follow-up questionnaires have generally been sent every two years.

Detailed dietary questionnaires were added in 1980 and repeated over time, allowing researchers to examine long-term eating patterns rather than relying on a single dietary measurement.

Why Is This Study So Important for Nutrition Research?

Many chronic diseases take years or decades to develop. A very large prospective cohort followed over such a long period allows researchers to examine whether earlier eating patterns and lifestyle factors are associated with diseases that appear much later.

The Nurses’ Health Study has generated thousands of scientific papers on nutrition and chronic disease.

What Nutrition Questions Have Researchers Studied?

Researchers have examined questions involving dietary fats and heart disease, type 2 diabetes, fruits and vegetables, red and processed meat, beverages, overall dietary patterns, and healthy aging.

There is therefore no single “Nurses’ Health Study nutrition paper.” The cohort has been used to answer many different research questions over decades.

One Landmark Nutrition Paper

A 1997 analysis examined dietary fat intake and coronary heart disease risk among women in the Nurses’ Health Study.

• PubMed record — 1997 dietary-fat paper
  The U.S. National Library of Medicine’s record for Dietary Fat Intake and the Risk of Coronary Heart Disease in Women.
• DOI — permanent study identifier
  The DOI is the paper’s permanent digital identifier and should continue to direct readers to the official journal page even if the journal’s web address changes.
• Official journal page — New England Journal of Medicine
  The official publisher page for this landmark Nurses’ Health Study nutrition analysis.

What Are the Strengths of the Nurses’ Health Study?

Its strengths include its very large size, decades of follow-up, repeated measurements of diet and lifestyle, and detailed information about many factors that could affect health.

These features allow researchers to study long-term relationships that would be very difficult or impossible to test in randomized trials lasting decades.

An Important Limitation

The Nurses’ Health Study is observational. Researchers observe what participants eat and how their health changes; they do not randomly assign women to different lifelong diets.

For that reason, the study can identify associations but cannot by itself prove that a particular food or dietary pattern caused or prevented a disease.

Why Were Only Women Included?

The original Nurses’ Health Study specifically recruited female registered nurses. That gave researchers a large, relatively stable group of participants who could provide detailed health information over many years.

However, it also meant that the original cohort could not directly answer whether the same diet and lifestyle relationships applied to men.

What About Men?

To study many of the same questions in men, researchers later established the Health Professionals Follow-Up Study, which began in 1986 with male health professionals.

Together, the Nurses’ Health Study and the Health Professionals Follow-Up Study have provided valuable information about how diet and lifestyle are associated with long-term health in both women and men.

The Nurses’ Health Study II and III

The research program later expanded with additional cohorts. The Nurses’ Health Study II began in 1989 with a younger generation of female nurses, and Nurses’ Health Study 3 began in 2010.

Together, these cohorts have allowed researchers to examine health across different generations and stages of adult life.

Why Is This Included Under “What Happens Over a Lifetime?”

The great strength of the Nurses’ Health Study is time. Researchers have been able to watch health patterns unfold over decades.

That long perspective helps answer questions short-term trials cannot: whether everyday eating and lifestyle patterns are associated with health and chronic disease many years later.