Table 1.

Descriptive statistics of participant characteristics according to study group: female students (n 100) attending two middle schools in average-income areas of Qom, Iran, April–June 2011

	Experimental group		Control group
Variable	n	%	n	%
Occupation of father
Self-employed	22	44	18	36
Employee	14	28	9	18
Casual labourer	11	22	16	32
Retired	3	6	7	14
Occupation of mother
Self-employed	3	6	2	4
Employee	3	6	2	4
Household duties	44	88	46	92
Father's education level
Illiterate	3	6	3	6
≤12th grade	39	78	43	86
>12th grade	8	16	4	8
Mother's education level
Illiterate	4	8	2	4
≤12th grade	44	88	46	92
>12th grade	2	4	2	4
Family size	50	100	50	100
Mean	5·52		5·38
sd	1·40		1·19
Sleep time
Before 22.00 hours	8	16	8	16
22.00 to 23.00 hours	22	44	16	32
23.00 to 00.00 hours	12	24	20	40
After 00.00 hours	8	16	6	12
Dinner time
Before 20.00 hours	12	24	9	18
20.00 to 22.00 hours	31	62	37	74
22.00 to 00.00 hours	6	12	3	6
After 00.00 hours	1	2	1	2
Time of waking up
Before 06.00 hours	17	34	11	22
06.00 to 06.30 hours	21	42	25	50
06.30 to 07.00 hours	12	24	14	28
Participation for preparing breakfast
Always	10	20	8	16
Sometimes	28	56	27	54
Never	12	24	15	30
Responsible for preparing breakfast
Mother	44	88	40	80
Other family members	3	6	2	4
Student	3	6	8	16