Table 4.

Multivariate-adjusted differences in intact parathyroid hormone in non-Hispanic blacks

Variable	Number	Difference in PTH (pg/ml)	95% CI	p, trend
Age (years)
<30	673	Referent		<0.01
30–39	281	3.5	0.6, 6.5
40–49	307	5.0	1.9, 8.0
50–59	199	6.6	3.7, 9.4
≥60	332	8.0	5.4, 10.7
Gender
Male	886	Referent
Female	906	4.5	1.9, 7.0
Body mass index (kg/m2)
<21	164	−4.0	−7.9, 0.0	0.05
21–24	365	Referent
25–29	511	0.1	−2.3, 2.5
30–34	381	−2.1	−4.7, 0.5
≥35	344	2.2	−1.3, 5.6
Smoking
Never	827	Referent
Past	262	0.4	−2.4, 3.2
Current	373	−6.1	−8.7, −3.5
Number of cigarettes per daya
<10	115	Referent		<0.01
10–19	104	−3.2	−8.5, 2.0
≥20	97	−6.0	−9.4, −2.6
Dietary calcium intake (mg/day)
<558	765	Referent		0.19
558–836	413	−0.7	−2.8, 1.4
837–1,246	350	−3.6	−6.3, −0.8
≥1,247	264	−1.6	−5.9, 2.7
Serum 25(OH) vitamin D (ng/mL)
<10	422	Referent		<0.01
10–13	477	−3.5	−6.4, −0.6
14–18	479	−4.0	−7.3, −0.6
≥19	522	−8.8	−11.3, −6.3
Serum calcium (mg/dL)
<9.3	340	Referent		<0.01
9.3–9.4	373	0.9	−2.0, 3.8
9.5–9.6	395	−0.6	−3.6, 2.4
≥9.7	684	−5.1	−7.6, −2.6
Serum phosphorous (mg/dL)
<3.5	431	Referent		0.71
3.5–3.7	402	1.7	−0.3, 3.6
3.8–4.1	462	1.4	−1.3, 4.2
≥4.2	497	0.0	−2.3, 2.4
Serum uric acid (mg/dL)
<4.3	418	Referent		<0.01
4.3–5.1	421	3.5	0.4, 6.7
5.2–6.0	287	4.7	2.3, 7.2
≥6.1	215	5.5	3.0, 8.1
Serum retinol (μg/dL)
<49.2	869	Referent		0.65
49.2–58.7	412	1.5	−0.5, 3.5
58.8–69.5	287	0.0	−3.0, 3.0
≥69.6	215	1.9	−1.4, 5.1

Note: Covariates in the multivariate regression model are adjusted for age, gender, body mass index, smoking status, dietary calcium intake, dietary protein intake, season of blood draw, serum 25(OH)D serum calcium, serum phosphorus, serum creatinine, serum uric acid, serum retinol, and fasting status

^aModel limited to participants who reported currently smoking