Table 2.

Adjusted 8-year change (95% CI) in QTc interval, QRSc duration, and JTc intervala from baseline to follow-up ECG examination, by lead biomarker concentration at baseline, among participants who were free of IVCD, AVCD, and arrhythmia at baseline ECG.

Table 2. Adjusted 8-year change (95% CI) in QTc interval, QRSc duration, and JTc intervala from baseline to follow-up ECG examination, by lead biomarker concentration at baseline, among participants who were free of IVCD, AVCD, and arrhythmia at baseline ECG.
Lead biomarker level		n		QTc		QRSc		JTc
Tibia lead tertile (µg/g)
< 16		191		Reference		Reference		Reference
16.0–23		208		7.49 (1.22 to 13.75)		0.52 (–3.60 to 4.65)		7.84 (1.23 to 14.45)
> 23		195		7.94 (1.42 to 14.45)		5.94 (1.66 to 10.22)		3.19 (–3.68 to 10.05)
p for trend test				0.03		0.005		0.52
Patella lead tertile (µg/g)
< 22		207		Reference		Reference		Reference
22–33		190		4.14 (–2.19 to 10.46)		2.87 (–1.02 to 7.33)		0.94 (–5.73 to 7.61)
> 33		202		2.69 (–3.68 to 9.06)		3.16 (–1.34 to 7.07)		0.53 (–6.18 to 7.23)
p for trend test				0.45		0.20		0.90
Blood lead tertile (µg/dL)
< 4		240		Reference		Reference		Reference
4–6		153		1.72 (–4.94 to 8.38)		2.76 (–1.65 to 7.17)		–0.11 (–7.09 to 6.87)
> 6		196		–3.54 (–9.74 to 2.66)		1.51 (–2.58 to 5.61)		–6.15 (–12.63 to 0.34)
p for trend test				0.32		0.40		0.08
aAdjusted for age (years) and age squared, education (≤ high school, some college, college graduate, or graduate school), smoking (never, former, or current and pack-years), BMI (kg/m2), albumin-adjusted serum calcium (mg/dL), and diabetes status (yes/no) at baseline, as well as years between ECG tests and QT-prolongation drugs (yes/no) at the time of ECG measurement. The measures analysis approach includes participants who did not have a follow-up ECG (see “Materials and Methods”).