title: 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.
abstract: BACKGROUND
  Cultural pressures to be thin and tall are postulated to cause people to misreport their body weight and height towards more socially normative (i.e., desirable) values, but a paucity of direct evidence supports this idea. We developed a novel non-linear approach to examining weight, height, and BMI misreporting biases and used this approach to examine the association between socially non-normative weight and misreporting biases in adults.
  
  
  METHODS
  The Survey of Lifestyles, Attitudes, and Nutrition 2007 (SLÁN 2007), a nationally representative survey of the Republic of Ireland (N = 1942 analyzed) was used. Self-reported weight (height) was classified as under-reported by ≥ 2.0 kg (2.0 cm), over-reported by ≥ 2.0 kg (2.0 cm), or accurately reported within 2.0 kg (2.0 cm) to account for technical errors of measurement and short-term fluctuations in measured weight (height). A simulation strategy was used to define self-report-based BMI as under-estimated by more than 1.40 kg/m2, over-estimated by more than 1.40 kg/m2, or accurately estimated within 1.40 kg/m2. Patterns of biases in self-reported weight, height, and BMI were explored. Logistic regression was used to identify factors associated with mis-estimated BMI and to calculate adjusted odds ratios (AOR) and 99% confidence intervals (99%CI).
  
  
  RESULTS
  The patterns of bias contributing the most to BMI mis-estimation were consistently, in decreasing order of influence, (1) under-reported weight combined with over-reported height, (2) under-reported weight with accurately reported height, and (3) accurately reported weight with over-reported height. Average bias in self-report-based BMI was -1.34 kg/m2 overall and -0.49, -1.33, and -2.66 kg/m2 in normal, overweight, and obese categories, respectively. Despite the increasing degree of bias with progressively higher BMI categories, persons describing themselves as too heavy were, within any given BMI category, less likely to have under-estimated BMI (AOR 0.5, 99%CI: 0.3-0.8, P < 0.001), to be misclassified in a lower BMI category (AOR 0.3, 99%CI: 0.2-0.5, P < 0.001), to under-report weight (AOR 0.5, 99%CI: 0.3-0.7, P < 0.001), and to over-report height (OR 0.7, 99%CI: 0.6-1.0, P = 0.007).
  
  
  CONCLUSIONS
  A novel non-linear approach to examining weight, height, and BMI misreporting biases was developed. Perceiving oneself as too heavy appears to reduce rather than exacerbate weight, height, and BMI misreporting biases.
authors: Department of Epidemiology and Public Health & HRB Centre for Health and Diet Research, University College Cork, Ireland. jon.brestoff@gmail.com
authors: Jonathan R
authors: JR
authors: Brestoff
authors: Ivan J
authors: IJ
authors: Perry
authors: Jan
authors: J
authors: Van den Broeck
references: Eur J Clin Nutr. 2006 Mar;60(3):372-7
references: 16278688
references: BMC Public Health. 2009 Nov 19;9:421
references: 19922675
references: Am J Epidemiol. 1987 Jan;125(1):122-6
references: 3788941
references: Obes Res. 1999 Jul;7(4):334-41
references: 10440589
references: Econ Hum Biol. 2011 Jan;9(1):78-91
references: 20621569
references: BMC Public Health. 2010 Sep 17;10:560
references: 20849632
references: Int J Behav Nutr Phys Act. 2006 Jul 19;3:17
references: 16854220
references: Int J Obes Relat Metab Disord. 2000 May;24(5):663-5
references: 10849592
references: Am J Clin Nutr. 1990 Dec;52(6):1125-33
references: 2239790
references: Health Econ. 2007 Sep;16(9):945-66
references: 17605138
references: Scand J Soc Med. 1987;15(3):191-8
references: 3616534
references: Int J Obes Relat Metab Disord. 1992 Jan;16(1):1-9
references: 1314237
references: Am J Epidemiol. 1982 Feb;115(2):223-30
references: 7058781
references: BMC Public Health. 2001;1:11
references: 11716792
references: J Epidemiol Community Health. 1996 Feb;50(1):105-6
references: 8762365
references: Public Health Nutr. 2002 Aug;5(4):561-5
references: 12186665
references: Soc Sci Med. 2009 Jan;68(2):251-9
references: 19059688
references: J Public Health Med. 1998 Jun;20(2):206-10
references: 9675741
references: Int J Obes Relat Metab Disord. 2000 Sep;24(9):1111-8
references: 11033979
references: Obes Rev. 2007 Jul;8(4):307-26
references: 17578381
references: Nutr J. 2005 Oct 06;4:27
references: 16209706
references: Obesity (Silver Spring). 2007 Jan;15(1):197-208
references: 17228048
references: Popul Health Metr. 2009 Jan 06;7:2
references: 19126232
references: J R Soc Med. 2006 May;99(5):250-7
references: 16672759
references: J Am Diet Assoc. 2001 Jan;101(1):28-34; quiz 35-6
references: 11209581
references: Econ Hum Biol. 2008 Mar;6(1):181-90
references: 17482531
references: Int J Obes Relat Metab Disord. 1993 Nov;17(11):663-7
references: 8281225