The NHS started in 1976 with the enrollment of 121,700 US registered
female nurses aged 30 to 55 years, who replied to a mailed health
questionnaire.40 The HPFS commenced in 1986 when 51,529 malehealth professionals agreed to join a similarly designed prospective
cohort analysis.41 Participants were monitored using biennial questionnaires
covering health status, lifestyle tendencies, and dietary
habits. Follow-up rates were high (>85% of the total possible persontime).
The Human Research Committees of Brigham and Women’s
Hospital and Massachusetts Eye and Ear Infirmary approved this study;
furthermore, the research adhered to the Declaration of Helsinki
tenets.