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Table 2 Association of various factors and estimating BMI beyond or within ±1.40 kg/m2.

From: Challenging the role of social norms regarding body weight as an explanation for weight, height, and BMI misreporting biases: Development and application of a new approach to examining misreporting and misclassification bias in surveys

Self-reported BMI:

Under-Estimated

Correctly Estimated

Over-Estimated

 

BMID (self-reported - measured):

< -1.40 kg/m2

Within ±1.40 kg/m2

> 1.40 kg/m2

 
 

N = 852 (43.8%)

N = 1000 (51.4%)

N = 93 (4.8%)

 
 

N

%

N

%

N

%

P value

BMI Category §

       

   Underweight

0

0.0

13

1.3

2

2.2

 

   Normal Weight

153

18.0

490

49.0

48

51.6

 

   Overweight

371

43.5

363

36.3

31

33.3

 

   Obese, Class I

233

27.3

107

10.7

8

8.6

 

   Obese, Class II

75

8.8

21

2.1

2

2.2

 

   Obese, Class III

20

2.3

6

0.6

2

2.2

< 0.001

Sex

       

   Male

366

43.0

449

44.9

47

43.0

 

   Female

486

57.0

551

55.1

46

57.0

0.327

Age

       

   18-29 y

90

10.6

184

18.4

16

17.2

 

   30-44 y

202

23.7

329

32.9

34

36.6

 

   45-64 y

331

38.8

366

36.6

29

31.2

 

   65+ y

229

26.9

121

12.1

14

15.1

< 0.001

Social class §§

       

   SC 1-2

334

37.6

382

39.8

26

26.8

 

   SC 3-4

366

41.2

372

38.8

40

41.2

 

   SC 5-6

119

13.4

134

14.0

20

20.6

 

   Unclassified

70

7.9

71

7.4

11

11.3

0.134

Current smoking status

       

   Former smoker

238

27.9

227

22.7

15

16.1

 

   Non-smoker

431

50.6

479

47.9

43

46.2

 

   Smoker

183

21.5

294

29.4

35

37.6

< 0.001

Alcohol consumption

       

   Never

183

21.6

137

13.7

23

25.0

 

   Monthly or less

145

17.1

150

15.0

25

27.2

 

   3-4 times/month

198

23.3

268

26.8

19

20.7

 

   2-3 times/week

235

27.7

338

33.8

18

19.6

 

   4 or more times/week

88

10.4

107

10.7

7

7.6

< 0.001

Marital status

       

   Single (never married)

185

21.8

244

24.5

28

30.1

 

   Married/Cohabiting

538

63.3

641

64.3

53

57.0

 

   Divorced/Separated/Widowed

127

14.9

112

11.2

12

12.9

0.066

Education

       

   Some/Completed Primary School

138

16.2

113

11.3

18

19.4

 

   Some/Completed Secondary School

387

45.4

423

42.3

48

51.6

 

   Diploma/Certificate

156

18.3

222

22.2

11

11.8

 

   Bachelors/Postgraduate Degree

171

20.1

242

24.2

16

17.2

0.001

Ethnicity

       

   White

826

98.2

971

97.9

90

96.8

 

   Black

5

0.6

4

0.4

1

1.1

 

   Asian

3

0.4

8

0.8

2

2.2

 

   Other

7

0.8

9

0.9

0

0.0

0.392

Physical Activity

       

   High IPAQ Score

221

25.9

214

21.4

25

26.9

 

   Medium IPAQ Score

425

49.9

514

51.4

47

50.5

 

   Low IPAQ Score

206

24.2

272

27.2

21

22.6

0.156

Self-described weight §§§

       

   About the right weight

419

49.6

607

60.8

48

51.6

 

   Too heavy

377

44.6

324

32.5

35

37.6

 

   Too light

22

2.6

42

4.2

3

3.2

 

   Not sure

27

3.2

25

2.5

7

7.5

<0.001

Attempting to manage weight

       

   No

406

47.7

540

54.0

49

52.7

 

   Lose weight

320

37.6

294

29.4

32

34.4

 

   Maintain weight

118

13.8

157

15.7

12

12.9

 

   Gain weight

8

0.9

9

0.9

0

0.0

0.020

  1. BMI, body mass index; SC, social class; IPAQ, International Physical Activity Questionnaire.
  2. § BMI categories defined as: Underweight (<18.5 kg/m2), Normal Range (18.5-24.9 kg/m2), Overweight (25.0-29.9 kg/m2), Class I Obese (30.0-34.9 kg/m2), Class II Obese (35.0-39.9 kg/m2), and Class III Obese (40.0 + kg/m2).
  3. §§ Household social class defined according occupation type, as per methods in ref. [23].
  4. §§§ Self-described weight taking into account one's age and height.
  5. All comparisons were made using Pearson chi-squared tests.