title: Validity of self-measured waist circumference in adults at risk of type 2 diabetes and cardiovascular disease.
abstract: BACKGROUND
  Waist circumference (WC) is used to indirectly measure abdominal adipose tissue and the associated risk of type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). Because of its easy implementation and low cost, self-measured WC is commonly used as a screening tool. However, discrepancies between self-measured and objectively measured WC may result in misclassification of individuals when using established cut-off values. The aim of this study was to determine the accuracy of self-measured WC in adults at risk of T2DM and/or CVD, and to determine the anthropometric, demographic and behavioural characteristics associated with bias in self-measured WC.
  
  
  METHODS
  Self-measured and objectively measured WC was obtained from 622 participants (58.4% female; mean age 43.4 ± 5.3 years) in the Hoorn Prevention Study. The associations of gender, age, educational level, body mass index, smoking status, dietary habits, physical activity and sedentary behaviour with the discrepancies between self-measured and objectively measured WC were analysed using independents t-test and one-way ANOVA. Bland-Altman plots were used to plot the agreement between the two measures.
  
  
  RESULTS
  On average, self-measured WC was overestimated by 5.98 ± 4.82 cm (P < 0.001). Overestimation was consistent across all subgroups, but was more pronounced in those who were younger and those with lower educational attainment.
  
  
  CONCLUSIONS
  The results support self-measured WC as a useful tool for large-scale populations and epidemiological studies when objective measurement is not feasible, but overestimation should be taken into account when screening adults at risk of T2DM and/or CVD.
authors.forename: Ana María
authors.initials: AM
authors.lastname: Contardo Ayala
authors.forename: Giel
authors.initials: G
authors.lastname: Nijpels
authors.forename: Jeroen
authors.initials: J
authors.lastname: Lakerveld
mesh_terms: D000328:Adult; D000368:Aged; D000886:Anthropometry / Q000379:methods; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000209:etiology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D012307:Risk Factors; D057566:Self Report; D055105:Waist Circumference