Tab. III.

Relation between the tested characteristics

Relation between		Group II		Group III
		Correlation coefficient (r)	Statistical significance	Correlation coefficient (r)	Statistical significance
6-HMS – D	ISI	–0.594	< 0.001	–0.707	< 0.001
	BMI	–0.020	> 0.05	–0.651	< 0.001
	WHR	0.022	> 0.05	–0.322	> 0.05
6-HMS – N	ISI	–0.810	< 0.001	–0.821	< 0.001
	BMI	–0.105	> 0.05	–0.756	< 0.001
	WHR	0.032	> 0.05	–0.339	> 0.05

6-HMS – 6-hydroxymelatonin sulphate, D – excretion during the day: µg/15 h, N – nocturnal excretion: µg/9 h, ISI – Insomnia Severity Index, BMI – body mass index, WHR – waist-hip ratio