Nurses' Health Study
The Nurses' Health Study, established in 1976 by Dr. Frank Speizer, and the Nurses' Health Study II, established in 1989 by Dr. Walter Willett, were long-term epidemiological studies conducted on women's health. The study followed 121,700 female registered nurses since 1976 and 116,000 female nurses since 1989 to assess risk factors for cancer and cardiovascular disease. The studies are among the largest investigations into risk factors for major chronic diseases in women ever conducted. The studies include clinicians, epidemiologists, and statisticians at the Channing Laboratory. Participating organizations from the Massachusetts medical community include the Harvard Medical School, Harvard School of Public Health, and several Harvard-affiliated hospitals, including Brigham and Women's Hospital, Dana–Farber Cancer Institute, Children's Hospital Boston, and Beth Israel Deaconess Medical Center.
The study is recruiting a new cohort of 100,000 female licensed practical nurses (LPNs) and registered nurses (RNs) (or those studying to become one) aged 20-46 called the Nurses' Health Study 3 (NHS3). NHS3 is completely online, using social media for recruitment.
A cohort of nurses aged 30 to 55 were initially surveyed in 1976 and biennially thereafter. A second cohort of nurses were enrolled in 1989.
Over time additional questions have been added, most notably the dietary assessment added in 1980. Deaths, usually reported by kin or by postal authorities, were followed up. Where possible and permitted, in cases suggestive of cardiovascular disease/coronary heart disease the followup went beyond death certificates to gather available documentation from autopsy reports and other records. Mortality followup is better than 98 percent.
In 1996, over 16,000 children of women in the second Nurses' Health Study cohort were enrolled in their own follow-up study called the Growing Up Today Study, or GUTS.
Selected studies 
Studies to date have led to the publication of hundreds of peer-reviewed papers.
NHS researchers have examined the effect of exposures like smoking, oral contraceptive use, alcohol consumption, and diet on disease risk. 
|Breast Cancer||Coronary Heart Disease (CHD)/Stroke||Colon Cancer||Hip Fracture||Cognitive Functioning||Eye Disease|
|Smoking||No relation with past or current smoking||Strong positive association with CHD and stroke; risk reduced within 2-4 years of smoking cessation.||Increases risk of colon cancer||Increases risk of hip fracture for current smokers. Risk increases with greater number of cigarettes smoked per day.||Not examined.||Increases risk of cataracts and “wet” AMD (the most severe form of Age-related Macular Degeneration).|
|Oral Contraceptives||Current use increases risk. Past use no association.||Current use increases risk. Past use no association.||Reduces risk of colon cancer.||Not examined.||Not examined.||Reduces risk of “wet” AMD.|
|Alcohol||One or more drinks per day increases risk.||Moderate alcohol intake reduces the risk of CHD.||Two or more drinks per day increases risk.||High consumption increases the risk of hip fracture. However, low or moderate consumption is associated with greater bone density.||Moderate intake (½ –1 serving per day) reduces risk of cognitive impairment.||No relation to age related eye diseases.|
|Diet||Higher intake of red meat increases risk of premenopausal breast cancer.||A Mediterranean-type diet reduces risk of incident CHD and stroke. Fish intake reduces risk of stroke. Nut and wholegrain consumption reduces risk of CHD. Refined carbohydrates and trans fats increase risk.||Higher intakes of folate, vitamin B6, calcium and vitamin D reduces risk. High intake of red and processed meats increases risk.||Reduction of risk with calcium supplement use among women with low calcium diets; higher dietary calcium intake has no effect. Vitamin D intake reduces risk and retinol intake increases risk.||Higher vegetable intake, especially green leafy vegetables, reduces risk of cognitive impairment.||Some antioxidants reduce risk of cataracts and AMD. Higher intake of fish may reduce risk of cataracts and AMD.|
- http://www.channing.harvard.edu/nhs/?page_id=73 NHS official site - participating organizations
- Nurses' Health Study 3 (official site)
- http://www.facebook.com/nhs3.org NHS3 on Facebook
- http://www.twitter.com/nhs3 NHS3 on Twitter
- http://ccn.aacnjournals.org/content/31/6/9.full NHS3 appeal in December 2011 issue of Critical Care Nurse
- List of NHS publications indexed by year
- PBS Frontline interview with Walter Willett (April 8, 2004)