Table 2. Waist Circumference (Quartiles) and Risk for Incident Primary Hyperparathyroidism.

	Waist Circumference
	Q1	Q2	Q3	Q4	P-trend
Range (cm)	≤68.6	68.7-76.2	76.3-86.4	≥86.5
Median waist circumference (cm)a	66.0	71.1	78.7	91.4
Incident Cases of P-HPTH	73	79	112	135
Person-years of Follow-Up	354,014	330,382	389,620	340,221
Age-adjusted RR	Ref	1.32 (0.96,1.82)	1.65 (1.23, 2.22)	2.09 (1.57, 2.79)	<0.001
Multivariate-adjusted Model 1 RR*	Ref	1.29 (0.94, 1.78)	1.57 (1.16, 2.12)	1.96 (1.45, 2.65)	<0.001
Multivariate-adjusted Model 2 RR**	Ref	1.34 (0.97, 1.86)	1.70 (1.24, 2.31)	2.27 (1.63, 3.18)	<0.001
Multivariate-adjusted Model 3 RR***	Ref	1.30 (0.95, 1.80)	1.61 (1.19, 2.19)	2.06 (1.52, 2.81)	<0.001

^aData from baseline in 1986

^*Model 1: Multivariable model includes age, race, smoking status (past, current, never), physical activity (quintiles), menopausal status (pre or post), postmenopausal hormone use (yes or no), physical examination in prior two years, bisphosphonate use, history of hypertension, diabetes, chronic kidney disease, congestive heart failure, or osteoporosis, total vitamin D and vitamin A intake, supplemental calcium and alcohol intake, dietary intakes of calcium, magnesium, and protein, and UV-B radiation flux.

^**Model 2: Multivariable model includes adjustment for all variables in Model 1 and also BMI

^***Model 3: Multivariable model includes adjustment for all variables in Model 1 and also predicted 25(OH)D levels

Note: Waist circumference values for the year 2000 are shown; however waist circumference was updated over the course of the study.