Table 1.

General characteristics of the study group.

Subject	Number of Subjects (n)	Percentage of Subject (%)
Sex
Girls	1465	47.00
Boys	1662	53.00
Age groups [years]
<3	20	0.64
3–6	146	4.67
7–11	1156	36.97
12–18	1805	57.72
Place of residence
Village	1603	51.26
City under 20,000 residents	414	13.24
City with 20,000 to 100,000 residents	793	25.36
City over 100,000 residents	317	10.14
Medical history
Children with chronic disease	638	20.40
Children without chronic disease	2489	79.60