Table 4.

Effect of vitamin D treatment on ECG measures.

Normal distribution	Placebo	Vitamin D		P-value
	Mean ± SD	Mean ± SD	Net change (95% CI)
PR interval, ms			− 0.48 (− 2.35, 1.39)	0.62
Baseline	171 ± 25	174 ± 28
2-year	174 ± 27	176 ± 30
P wave duration, ms			− 1.49 (− 3.36, 0.38)	0.12
Baseline	114 ± 13	114 ± 13
2-year	110 ± 14	109 ± 14
P wave amplitude, mV			0.001 (− 0.003, 0.004)	0.67
Baseline	0.123 ± 0.037	0.123 ± 0.036
2-year	0.121 ± 0.035	0.121 ± 0.037
P terminal force, mVms			− 204.5 (− 490.2, 81.3)	0.16
Baseline	2403 ± 2143	2349 ± 1912
2-year	3256 ± 2302	3002 ± 2230
QRS duration, ms			− 0.003 (− 0.93, 0.92)	0.99
Baseline	94 ± 13	93 ± 13
2-year	95 ± 14	94 ± 14
Cornell, mV			− 0.44 (− 0.87, − 0.01)	0.044
Baseline	1.18 ± 0.56	1.14 ± 0.52
2-year	1.31 ± 0.56	1.23 ± 0.53
Heart rate, bpm			0.44 (− 1.38, 0.50)	0.36
Baseline	65 ± 10	65 ± 10
2-year	64 ± 10	63 ± 10

Non-normal distribution	Placebo	Vitamin D		P-value
	Median (25–75 percentile)	Median (25–75 percentile)	Net change %(95% CI)
QTc interval 1, ms			0.42 (− 0.21, 1.05)	0.2
Baseline	416 (413–419)	416 (413–418)
2-year	419 (416–421)	420 (418–423)
QTc interval 2, ms			0.15 (− 0.30, 0.61)	0.50
Baseline	426 (424–428)	425 (424–427)
2-year	426 (424–428)	426 (424–428)
SDNN, ms			0.08 (− 7. 72, 8.55)	0.98
Baseline	18.0 (17.1–19.0)	18.8 (17.8–19.8)
2-year	17.3 (16.3–18.2)	18.2 (17.2–19.2)
RMSSD, ms			0.52 (− 7.28, 8.98)	0.90
Baseline	18.1 (17.1–19.2)	19.0 (17.9–20.1)
2-year	18.2 (17.2–19.3)	19.3 (18.2–20.5)

Treatment effect model adjusted for age, gender, race, BMI mean blood pressure, and active treatment.

QTc interval 1 represents QTc calculated with the Framingham formula, QTc interval 2 with the Fredericia formula.