Table 3 Children data for waves 7, 9, and 11 (data for waves 8, and 10 shown in Additional file 1: Table S2)

Duration of data sampling for specific follow-up (FU) wave

04/17—07/18

04/19—07/20

04/21—07/22

Children, N

496

353

249

 Set of twins

18

11

5

Age (n observations)

(496)

(353)

(249)

 Mean (SD)

5.1 (0.1)

7.1 (0.1)

9.1 (0.1)

SARS-COV-2-infection

–

–

(249)

 Ever, N (%)

–

–

15 (6.0)

Health related quality of life (KINDL)^a

pre-pandemic

(479)

pre-pandemic

(280)

during pandemic

(57)

during pandemic

(242)

Total score, Mean (SD),

Median (Q1, Q3)

80.6 (0.4),

81.3 (76.0, 86.5)

84.2 (0.5),

84.4 (79.2, 90.1)

81.5 (1.1),

81.3 (77.1, 86.5)

81.9 (0.6),

83.3 (77.1, 88.5)

N

(494)

(289)

(62)

(245)

Family, Mean (SD),

Median (Q1, Q3)

82.5 (0.5),

81.3 (75.0, 93.8)

83.1 (0.7),

81.3 (75.0, 93.8)

79.3 (1.5),

81.3 (75, 87.5)

81.8 (0.8),

81.3 (75.0, 93.8)

N

(494)

(289)

(62)

(245)

 Physical well-being, Mean (SD), Median (Q1, Q3)

84.3 (0.6),

87.5 (75.0, 93.8)

86.7 (0.7),

87.5 (81.3, 93.8)

87.3 (1.2),

87.5 (81.3, 93.8)

87.3 (0.9),

93.8 (81.3, 100.0)

N

(494)

(289)

(62)

(245)

 Emotional well-being,

 Mean (SD), Median (Q1, Q3)

86.0 (0.5),

87.5 (81.3, 93.8)

85.6 (0.7),

87.5 (75, 93.8)

83.7 (1.4),

84.4 (75, 87.5)

82.6 (0.8),

87.5 (75.0, 93.8)

N

(492)

(289)

(62)

(245)

 Self-esteem, Mean (SD), Median (Q1, Q3)

79.4 (0.6),

78.1 (75.0, 87.5)

78.9 (0.8),

75.0 (68.8, 87.5)

74.8 (1.9),

75.0 (68.8, 81.3)

76.8 (0.9),

75.0 (68.8, 87.5)

N

(493)

(289)

(58)

(244)

 Friends, Mean (SD),

 Median (Q1, Q3)

81.8 (0.5),

81.3 (75.0, 87.5)

80.7 (0.7),

81.3 (75.0, 87.5)

75.4 (2.5),

75 (68.8, 87.5)

80.9 (0.9),

81.3 (75.0, 93.8)

N

(482)

(280)

(58)

(243)

 School, Mean (SD),

 Median (Q1, Q3)

69.7 (0.4),

68.8 (62.5, 75.0)

89.5 (0.6),

93.8 (87.5, 100.0)

87.4 (1.5),

87.5 (81.3, 93.8)

81.8 (0.9),

81.3 (75.0, 93.8)

SDQ Strengths and Difficulties Questionnaire^b

(493)

(289)

(64)

(248)

Total Difficulties Score, Mean (SD),

Median (Q1, Q3)

7.1 (0.2),

6.3 (4.0, 9.0)

6.4 (0.3),

6.0 (3.0, 9.0)

7.5 (0.7),

6.0 (4.0, 10.0)

6.7 (0.3),

6.0 (3.0, 10.0)

 SDQ emotion, Mean (SD)

1.4 (0.07)

1.3 (0.09)

1.1 (0.2)

1.5 (0.1)

 SDQ behavior, Mean (SD)

1.9 (0.07)

1.5 (0.09)

2.0 (0.2)

1.5 (0.1)

 SDQ hyperactive, Mean (SD)

2.7 (0.1)

2.6 (0.1)

3.3 (0.3)

2.8 (0.2)

 SDQ peers, Mean (SD)

1.1 (0.07)

1.0 (0.09)

1.1 (0.2)

1.0 (0.09)

 SDQ prosocial, Mean (SD)

7.9 (0.08)

8.1 (0.1)

7.7 (0.3)

8.2 (0.1)

Physical Activity Score^c

(495)

(289)

(64)

(249)

 Mean (SD),

 Median (Q1, Q3)

0.4 (0.1),

1.0 (-1.0, 3.0)

1.6 (0.2),

1.0 (-1.0, 3.0)

1.8 (0.4),

2.0 (-1.0, 3.0)

1.2 (0.2),

1.0 (-1.0, 3.0)

Screen-time (h/week)^d

(491)

(287)

(62)

(248)

 Mean (SD),

 Median (Q1, Q3)

5.4 (0.2),

4.5 (2.0, 8.0)

6.9 (0.3),

5.0 (3.0, 9.0)

8.8 (0.9),

7.0 (4.1, 11.5)

10.9 (0.5),

8.6 (5.5, 14.5)

Time spent with books (h/week)^e

(491)

(287)

(62)

(248)

 Mean (SD),

 Median (Q1, Q3)

6.7 (0.2),

6.0 (3.5, 8.4)

6.7 (0.3),

5.3 (3.5, 8.4)

6.2 (0.6),

4.5 (3.5, 8.0)

6.7 (0.3),

5.4 (3.5, 9.0)