The Nurses' Health Study (NHS) began in 1976 when a cohort of 121,700 nurses aged 30-55 was assembled, by investigators from Harvard University, to improve our understanding of women’s health and the prevention of chronic diseases. The study design consisted of contacting the nurses every two years to complete questionnaires and undergo clinical examinations. While comparative epidemiological studies suffer from rapid depopulation, the NHS retained more than 94% of its original population. Better said, the nurses were incredibly committed to the purpose of the study and had the skills to sample their own blood, saliva, hair, nails and complete health-related surveys.
To celebrate the 40th anniversary of the NHS, a compendium of findings was published in the September 2016 issue of the American Journal of Public Health (AJPH). The reviews assembled provide unique perspective on the effects on women’s health of lifestyle, social and mental health determinants, biomarkers, genes, and proteins on most chronic diseases, including skin disorders, mental health occupational health, eye health, cardiovascular and renal disease as well as reproductive health, neurodegenerative disorders and life course exposures.
PCNA members will take great interest in the findings related to diet, lifestyle, biomarkers, genetic factors and risk of cardiovascular diseases (CVD) in the NHS:
- While there may have been no surprise that the study demonstrated increased CVD risk among those who smoked and were sedentary and overweight, an additional lifestyle survey demonstrated increased risk of CVD associated with shift work, poor sleep, phobic anxiety, depression, caregiving and job insecurity.
- Oral contraceptive use was found to increase the risk of CVD, while postmenopausal hormone use was found to lower the risk of coronary heart disease and raise the risk of stroke in all age groups.
- Very detailed nutritional surveys highlighted the importance of a heart-healthy diet, including a variety of fruits, vegetables, nuts, legumes, and whole grains while limiting the intake of red meats, saturated fat, sugar-sweetened beverages, and refined grains.
Women in the original NHS continue to be followed via biennial questionnaires, with many of the participants now in their 80’s and 90’s. The range of lifestyle, health outcome, and chronic disease data has greatly expanded over time, as has the data base and biorepository. Additional arms of the NHS have grown as well. In 1989, the Nurses' Health Study II was started, enrolling nurses aged 25 to 42, with the goal of better understanding the effects of oral contraceptives on women’s health. In 2010 the NHS 3 was started and is still enrolling nurses aged 19-49 in the US and Canada. This new study has increased diversity, with 14% of participants identifying themselves as from a racial or ethnic minority. In 2015. the enrollment expanded to include male nurses.
Our gratitude and congratulations go to those nurses who have participated in the NHS for any or all of its 40 years! Thanks to you and the many researchers involved in helping to expand the breadth of knowledge on risk factors and ways to prevent the major chronic diseases of our time, including CVD, cancer, diabetes, cognitive decline, reproductive disorders, depression, and anxiety… just to mention just a few!
To learn more about the Nurses' Health Study or to join NHS3, visit www.nurseshealthstudy.org.