| Title: |
An improved algorithm to harmonize child overweight and obesity prevalence rates |
| Authors: |
Cole, Tim J; Lobstein, Tim |
| Source: |
Pediatric Obesity , Article e12970. (2022) (In press). |
| Publisher Information: |
WILEY |
| Publication Year: |
2022 |
| Collection: |
University College London: UCL Discovery |
| Subject Terms: |
CDC; harmonization; IOTF; obesity; overweight; prevalence; WHO |
| Description: |
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. |
| Document Type: |
article in journal/newspaper |
| File Description: |
text |
| Language: |
English |
| Relation: |
https://discovery.ucl.ac.uk/id/eprint/10155184/1/An%20improved%20algorithm%20to%20harmonize%20child%20overweight%20and%20obesity%20prevalence%20rates.pdf; https://discovery.ucl.ac.uk/id/eprint/10155184/ |
| Availability: |
https://discovery.ucl.ac.uk/id/eprint/10155184/1/An%20improved%20algorithm%20to%20harmonize%20child%20overweight%20and%20obesity%20prevalence%20rates.pdf; https://discovery.ucl.ac.uk/id/eprint/10155184/ |
| Rights: |
open |
| Accession Number: |
edsbas.A4C93F6A |
| Database: |
BASE |