eprintid: 10155184 rev_number: 8 eprint_status: archive userid: 699 dir: disk0/10/15/51/84 datestamp: 2022-09-07 11:43:30 lastmod: 2022-09-07 11:43:30 status_changed: 2022-09-07 11:43:30 type: article metadata_visibility: show sword_depositor: 699 creators_name: Cole, Tim J creators_name: Lobstein, Tim title: An improved algorithm to harmonize child overweight and obesity prevalence rates ispublished: inpress divisions: UCL divisions: G25 divisions: D13 divisions: B02 keywords: CDC, harmonization, IOTF, obesity, overweight, prevalence, WHO note: © 2022 The Authors. Pediatric Obesity published by John Wiley & Sons Ltd on behalf of World Obesity Federation. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/). abstract: BACKGROUND: Prevalence rates of child overweight and obesity for a group of children vary depending on the BMI reference and cut-off used. Previously we developed an algorithm to convert prevalence rates based on one reference to those based on another. OBJECTIVE: To improve the algorithm by combining information on overweight and obesity prevalence. METHODS: The original algorithm assumed that prevalence according to two different cut-offs A and B differed by a constant amount dz $$ dz $$ on the z-score scale. However the results showed that the z-score difference tended to be greater in the upper tail of the distribution and was better represented by b × dz $$ b\times dz $$ , where b $$ b $$ was a constant that varied by group. The improved algorithm uses paired prevalence rates of overweight and obesity to estimate b $$ b $$ for each group. Prevalence based on cut-off A is then transformed to a z-score, adjusted up or down according to b × dz $$ b\times dz $$ and back-transformed, and this predicts prevalence based on cut-off B. The algorithm's performance was tested on 228 groups of children aged 6-17 years from 20 countries. RESULTS: The revised algorithm performed much better than the original. The standard deviation (SD) of residuals, the difference between observed and predicted prevalence, was 0.8% (n = 2320 comparisons), while the SD of the difference between pairs of the original prevalence rates was 4.3%, meaning that the algorithm explained 96.7% of the baseline variance (88.2% with original algorithm). CONCLUSIONS: The improved algorithm appears to be effective at harmonizing prevalence rates of child overweight and obesity based on different references. date: 2022-08-23 date_type: published publisher: WILEY official_url: https://doi.org/10.1111/ijpo.12970 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1973917 doi: 10.1111/ijpo.12970 lyricists_name: Cole, Timothy lyricists_id: TCOLE39 actors_name: Flynn, Bernadette actors_id: BFFLY94 actors_role: owner funding_acknowledgements: [National Institute for Health (NIH)]; R01 HD30880 [Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)]; R01 AG065357 [National Institute on Aging (NIA)]; R01DK104371 [National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)]; R01HL108427 [National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)]; D43 TW009077 [NIH Fogarty grant]; [China-Japan Friendship Hospital, Ministry of Health]; [Chinese National Human Genome Center at Shanghai]; [Beijing Municipal Center for Disease Prevention and Control] full_text_status: public publication: Pediatric Obesity article_number: e12970 pages: 10 event_location: England citation: Cole, Tim J; Lobstein, Tim; (2022) An improved algorithm to harmonize child overweight and obesity prevalence rates. Pediatric Obesity , Article e12970. 10.1111/ijpo.12970 <https://doi.org/10.1111/ijpo.12970>. (In press). Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10155184/1/An%20improved%20algorithm%20to%20harmonize%20child%20overweight%20and%20obesity%20prevalence%20rates.pdf