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Table 1 Characteristics of participants with complete data compared with participants with missing data or losses of follow-up, stratified by gender

From: Body mass index at 11 years and bone mass at age 18: path analysis within the 1993 Pelotas (Brazil) birth cohort study

Variables

Males

Females

N Mean (SD); percentage

N Mean (SD); percentage

Participants included in the analysis

Participants excluded from the analysisa

p-value

Participants included in the analysis

Participants excluded from the analysisa

p-value

Follow-up at 11 years

      

Family income

N = 1601

N = 590

 

N = 1706

N = 555

 
 

1219.77 (2966.82)

1054.02 (2403.48)

0.224b

1062.79 (1597.87)

849.28 (1565.43)

0.006b

Maternal education (years)

N = 1601

N = 572

 

N = 1706

N = 535

 

 0-4

24.9%

29.6%

0.099c

22.6%

35.9%

<0.001c

 5-8

42.5%

42.1%

 

43.5%

44.1%

 

 9-11

22.4%

20.1%

 

23.5%

13.6%

 

 ≥12

10.2%

8.2%

 

10.4%

6.4%

 

Skin color

N = 1601

N = 509

 

N = 1706

N = 507

 

 White

65.5%

60.5%

0.040c

65.2%

59.2%

0.013c

 Non-white

34.5%

39.5%

 

34.8%

40.8%

 

Total physical activity (minutes/week)

N = 1601

N = 515

 

N = 1706

N = 465

 
 

514.80 (523.77)

559.49 (563.32)

0.098b

347.41 (405.32)

325.42 (367.51)

0.29b

Smoking

N = 1601

N = 484

 

N = 1706

N = 487

 

 No

97.6%

96.3%

0.129c

98.1%

96.7%

0.061c

 Yes

2.4%

3.7%

 

1.9%

3.3%

 

BMI z scored

N = 1601

N = 583

 

N = 1706

N = 551

 
 

0.46 (1.22)

0.52 (1.35)

0.349b

0.27 (1.23)

0.31 (1.20)

0.531b

Follow-up at 18 years

      

Total physical activity (minutes/week)

N = 1601

N = 407

 

N = 1706

N = 381

 
 

855.53 (914.26)

910.45 (913.21)

0.279b

455.94 (583.28)

460.20 (521.76)

0.895b

Smoking

N = 1601

N = 414

 

N = 1706

N = 385

 

 No

86.2%

79.5%

0.001c

88.5%

81.0%

<0.001c

 Yes

13.8%

20.5%

 

11.5%

19.0%

 

BMI z scored

N = 1601

N = 372

 

N = 1706

N = 295

 
 

0.25 (1.15)

0.45 (1.39)

0.005b

0.44 (1.18)

0.47 (1.30)

0.753b

Fat mass (kg)

N = 1601

N = 369

 

N = 1706

N = 297

 
 

12.46 (8.72)

14.40 (12.60)

<0.001b

20.75 (8.90)

21.19 (11.60)

0.453b

Fat free mass (kg)

N = 1601

N = 369

 

N = 1706

N = 297

 
 

57.74 (7.04)

58.67 (8.25)

0.026b

40.15 (4.99)

40.67 (5.41)

0.101b

Height (m)

N = 1601

N = 369

 

N = 1706

N = 298

 
 

1.74 (0.07)

1.74 (0.08)

0.857b

1.61 (0.06)

1.61 (0.06)

0.874b

Calcium intake (mg/day)

N = 1601

N = 336

 

N = 1706

N = 316

 
 

709.16 (332.71)

726.61 (340.34)

0.384b

694.27 (351.62)

679.39 (364.83)

0.492b

Bone mineral content (g)

N = 1601

N = 302

 

N = 1706

N = 246

 
 

2963.12 (465.24)

2927.32 (441.61)

0.216b

2410.69 (396.08)

2411.90 (386.86)

0.964b

Bone mineral density (g/cm2)

N = 1601

N = 302

 

N = 1706

N = 246

 
 

1.22 (0.10)

1.22 (0.09)

0.544b

1.13 (0.08)

1.13 (0.08)

0.902b

  1. The 1993 Pelotas Birth Cohort. Brazil.
  2. N - Number of observations; SD - Standard deviation; BMI - body mass index
  3. aParticipants excluded from analysis due to losses of follow-up or missing data.
  4. bt-test
  5. cChi-square test
  6. dAccording to the World Health Organization for children and teenagers from 5 to 19 years.