Table 2.

Characteristics by BLL quartile of adults ≥ 17 years of age participating in the NHANES III DNA bank.

Characteristic	Quartile 1 (0.7–1.4 μg/dL)	Quartile 2 (1.5–2.3 μg/dL)	Quartile 3 (2.4–3.7 μg/dL)	Quartile 4 (3.8–52.9 μg/dL)	p-Value for trend
Median BLL (μg/dL)	0.70	1.90	3.00	5.00
ALAD2 carriers, 1-2/2-2 (%)	15.1	14.2	11.6	13.5
BP (mmHg)
Systolic BP	113.5 ± 0.41	116.9 ± 0.46	121.1 ± 0.81	124.6 ± 0.58	< 0.001
Diastolic BP	71.6 ± 0.45	73.0 ± 0.42	74.3 ± 0.44	75.3 ± 0.50	< 0.001
Systolic BP = 140 mmHg (%)a	3.0	7.2	11.9	15.1	< 0.001
Diastolic BP = 90 mmHg (%)a	3.2	4.6	6.2	8.0	< 0.001
Hypertension, yes (%)b	10.9	18.4	27.4	33.1	< 0.001
Race (%)
Non-Hispanic white	83.7	83.5	81.8	77.6
Non-Hispanic black	10.8	11.4	12.1	15.4	< 0.01
Mexican American	5.6	5.1	6.1	7.0
Age [years (%)]
17–39	71.3	50.6	39.7	28.9
40–59	21.6	32.6	32.8	35.5	< 0.001
≥ 60	7.1	16.9	27.5	35.6
Sex (%)
Male	26.6	40.2	53.8	69.1	< 0.001
Female	73.4	59.8	46.2	30.9
BMI (kg/m2)	26.66 ± 0.47	26.70 ± 0.21	26.70 ± 0.21	26.63 ± 0.22	0.9
Smoking history (%)
Current	14.2	21.7	29.8	36.6
Former	19.16	25.4	23.9	32.1	< 0.001
Never	66.7	52.9	46.3	31.3
Alcohol use (%)
None	52.5	50.8	46.0	40.6
< 4 drinks/week	31.6	28.4	27.2	24.3	< 0.001
≥ 4 drinks/week	15.9	20.9	26.8	35.2
Education (%)
< High school	16.6	15.6	25.7	32.2
Completed high school	36.7	33.1	34.2	34.7	< 0.001
Some college	46.7	51.2	40.2	33.1
Serum creatinine (mg/dL)	0.78 ± 0.01	0.83 ± 0.01	0.88 ± 0.01	0.94 ± 0.01	< 0.001
Serum calcium (mg/dL)	9.15 ± 0.03	9.17 ± 0.03	9.22 ± 0.03	9.21 ± 0.04	0.02
Log glycosylated hemoglobin (%)	1.64 ± 0.01	1.67 ± 0.01	1.70 ± 0.01	1.70 ± 0.01	< 0.001
Hematocrit (%)	40.72 ± 0.24	41.72 ± 0.14	42.83 ± 0.20	43.19 ± 0.16	< 0.001

Values are percent or mean ± SE.

^aSubject with systolic BP of ≥ 140 mmHg or diastolic BP of ≥ 90 mmHg not currently treated for hypertension.

^bHypertension defined as a self-report of currently taking antihypertensive medication, systolic BP of ≥ 140 mmHg, or diastolic BP of ≥ 90 mmHg.