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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.