Table 5.

Comparisons by severity cutoff of groups of sleep breathing parameters and serotonin findings.

	Mean ± SD		U	Z	p-Value
	AHI < 5	AHI ≥ 5
	N = 88	N = 17
TPH1	109.15 ± 119.233	155.75 ± 122.988	559.00	− 1.640	0.101
AADC	1384.70 ± 915.643	1047.40 ± 559.005	593.00	1.344	0.179
Serotonin	110.01 ± 55.773	93.41 ± 51.520	640.00	0.935	0.350

	AHI < 15	AHI ≥ 15
	N = 99	N = 6
TPH1	109.88 ± 118.851	229.15 ± 101.851	108.00	− 2.602	0.009
AADC	1343.09 ± 896.472	1115.65 ± 319.490	290.00	0.090	0.928
Serotonin	108.52 ± 55.552	87.60 ± 49.218	239.00	0.794	0.427

	AHI < 30	AHI ≥ 30
	N = 102	N = 3
TPH1	112.45 ± 119.378	260.92 ± 55.754	34.00	− 2.279	0.023
AADC	1335.88 ± 885.440	1133.14 ± 358.859	153.00	0.010	0.992
Serotonin	107.55 ± 55.752	99.67 ± 38.078	142.00	0.202	0.840

	ODI < 5	ODI ≥ 5
	N = 88	N = 17
TPH1	109.20 ± 118,911	155.47 ± 124,787	574.00	− 1.509	0.131
AADC	1380.75 ± 916,682	1067.84 ± 562,370	613.00	1.170	0.242
Serotonin	112.38 ± 56,053	81.12 ± 43,114	515.00	2.023	0.043

	AS < 93%	AS ≥ 93%
	N = 9	N = 96
TPH1	226.64 ± 175.134	106.38 ± 109.806	199.00	− 2.661	0.008
AADC	1091.39 ± 395.088	1352.47 ± 904.679	399.00	0.372	0.710
Serotonin	87.06 ± 35.832	109.22 ± 56.448	322.00	1.253	0.210

Apnea–hypopnea index (AHI), oxygen desaturation index (ODI), average oxygen saturation (AS), standard deviation (SD), tryptophan hydroxylase 1 (TPH1), aromatic l-amino acid decarboxylase (AADC).