Table 1.

Characteristics of Health Professionals Follow-up Study (HPFS) and Nurses’ Health Study (NHS) cohorts.

Cohort	N	Mean heme, SD (mg/day)	Mean body mass index, SD (kg/m2)	Mean age at baseline, SD (years)
HPFS Cases Controls	1998 725 1273	1.29 (0.43) 1.39 (0.43) 1.23 (0.42)	25.05 (3.46) 27.87 (3.82) 25.01 (2.74)	54.19 (8.36) 52.93 (8.16) 54.91 (8.39)
NHS Cases Controls	2773 1081 1692	1.36 (0.45) 1.41 (0.44) 1.33 (0.45)	26.08 (5.00) 28.66 (4.95) 24.43 (4.29)	47.47 (6.76) 47.31 (6.73) 47.57 (6.78)

SD, standard deviation.