1 Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
2 Department of Occupational and Environmental Health Sciences, West Virginia University School of Public Health, Morgantown, WV, USA.
3 Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA; Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA. Electronic address: xuehong.zhang@channing.harvard.edu.