What is ICAD?
Objective methods, such as accelerometers, have become a preferred option when measuring population levels of physical activity, examining trends in activity patterns and when examining associations between activity and health outcomes in young people.
The International Children’s Accelerometry Database (ICAD) project is a consortium including 20 partners which pooled and reduced raw accelerometer data using standardized methods. Data were processed to create comparable accelerometer variables in over 37,000 young people aged 3 to 18 years across studies from Europe, the US, Brazil and Australia. In addition, non-accelerometer data were harmonised in a transparent and structured way.
By pooling data from different studies the ICAD has the potential to:
- increase statistical power due to a large sample size
- create a more heterogeneous and potentially more representative sample
- standardize and optimize the analytical methods used in the generation of outcome variables, and
- provide a means to study the causes of inter-study variability in physical activity.
NEW! Release of ICAD 2
Early 2017, a new version of ICAD was released. Compared to the first release, the updated ICAD includes more longitudinal data and provides access to a wider range of non-accelerometer data. All accelerometer data has been reprocessed to ensure consistency across waves. Example harmonised variables have been derived for a range of demographic and health-related constructs; further data is available for harmonisation by individual researchers (see Data Harmonisation page).
ICAD funding and management
The initial ICAD project was funded by the National Prevention Research Initiative. ICAD is led by a Steering Committee including representatives from all contributing partners.
The ICAD is managed in collaboration by the MRC Epidemiology Unit, Loughborough University and Norwegian School of Sport Sciences. A Working Group manages the day-to-day running of ICAD. The ICAD Working Group consists of: Dr Andrew Atkin, Prof Ulf Ekelund, Dr Dale Esliger, Dr Bjorge H Hansen, Dr Lauren Sherar, and Dr Esther van Sluijs.
The database is managed by the MRC Epidemiology Unit and is publicly available for data requests from bona fide researchers across the world. For the purposes of ICAD data sharing the following definition of a bona fide researcher has been adopted (see p24).
Applying to use ICAD data
The ICAD is open for data requests as a supported access resource. Please find information regarding the application process to access the data below. General and pre-submission enquiries should be directed to Lauren Sherar (email@example.com). Please review the available variables, and the information provided on data harmonisation. Please contact firstname.lastname@example.org with data requests using the application form below. Data will be released in chronological order by date of proposal acceptance and is usually within 5 to 10 working days.
- General instructions for ICAD use
- ICAD online Data Dictionary
- ICAD application form
- Data use agreement
Publishing and presenting ICAD Data
- ICAD approved proposals and progress (updated May 2017)
- List of ICAD partners
- Log of changes to ICAD database
- ICAD symposium at ISBNPA Annual Meeting (June 2015, Edinburgh): see video here.
- Accelerometry data reduction settings for ICAD 2 (Dec 2015):
ICAD papers (most recent first)
- Moore JB, Beets MW, Brazendale K, Blair SN, Pate RR, Andersen LB, Anderssen SA, Grøntved A, Hallal PC, Kordas K, Kriemler S, Reilly JJ, Sardinha LB. Associations of Vigorous-intensity Physical Activity with Biomarkers in Youth. Med Sci Sports Exerc. 2017 Mar 8. [full text]
- Mitchell JA, Dowda M, Pate RR, Kordas K, Froberg K, Sardinha LB, Kolle E, Page A. Physical Activity and Pediatric Obesity: A Quantile Regression Analysis.Med Sci Sports Exerc. 2017 Mar;49(3):466-473. [full text]
- Sherar LB, Griffin TP, Ekelund U, Cooper AR, Esliger DW, van Sluijs EM, Bo Andersen L, Cardon G, Davey R, Froberg K, Hallal PC, Janz KF, Kordas K, Kriemler S, Pate RR, Puder JJ, Sardinha LB, Timperio AF, Page AS. Association between maternal education and objectively measured physical activity and sedentary time in adolescents. J Epidemiol Community Health. 2016 Jun;70(6):541-8. [full text]
- Corder K, Sharp SJ, Atkin AJ, Andersen LB, Cardon G, Page A, Davey R, Grøntved A, Hallal PC, Janz KF, Kordas K, Kriemler S, Puder JJ, Sardinha LB, Ekelund U, Van Sluijs EM, on behalf of the International Children’s Accelerometry Database (ICAD) Collaborators. Age-related patterns of vigorous-intensity physical activity in youth: the International Children’s Accelerometry Database. Prev Med Reports, 2016;4:17-22. [full text]
- Brazendale K, Beets MW, Bornstein DB, Moore JB, Pate RR, Weaver RG, Falck RS, Chandler JL, Andersen LB, Anderssen SA, Cardon G, Cooper A, Davey R, Froberg K, Hallal PC, Janz KF, Kordas K, Kriemler S, Puder JJ, Reilly JJ, SAlmon J, Sardinha LB, Timperio A, van Sluijs EMF, on behalf of the International Children’s Accelerometry Database (ICAD) Collaborators. Equating accelerometer estimates among youth: the Rosetta Stone 2. J Sci Med Sports, 2016 Mar;19(3):242-9. [full text]
- Cooper AR, Goodman A, Page AS, Sherar LB, Esliger DW, van Sluijs EM, Andersen LB, Anderssen S, Cardon G, Davey R, Froberg K, Hallal P, Janz KF, Kordas K, Kreimler S, Pate RR, Puder JJ, Reilly JJ, Salmon J, Sardinha LB, Timperio A, Ekelund U. Objectively measured physical activity and sedentary time in youth: the International children’s accelerometry database (ICAD). Int J Behav Nutr Phys Act. 2015 Sep 17;12:113. [full text]
- Hildebrand M, Kolle E, Hansen BJ, Collings PJ, Wijndaele K, Kordas K, Cooper AR, Sherar LB, Andersen LB, Sardinha LB, Kriemler S, Hallal P, Van Sluijs E, Ekelund U. Association between birth weight and objectively measured sedentary time is mediated by central adiposity: data in 10,793 youth from the International Children’s Accelerometry Database. Am J Clin Nutr, 2015 May;101(5):983-90 [full text]
- Goodman A, Page AS, Cooper AR; International Children’s Accelerometry Database (ICAD) Collaborators. Daylight saving time as a potential public health intervention: an observational study of evening daylight and objectively-measured physical activity among 23,000 children from 9 countries. Int J Behav Nutr Phys Act, 2014, Oct 23;11:84.[full text]
- Atkin AJ, Sharp SJ, Corder K, van Sluijs EM; on behalf of the International Children’s Accelerometry Database (ICAD) Collaborators. Prevalence and correlates of screen time in youth: an international perspective. Am J Prev Med, 2014 Sep 16 [full text]
- Kwon S, Janz KF; International Children’s Accelerometry Database (ICAD) Collaborators. Tracking of accelerometry-measured physical activity during childhood: ICAD pooled analysis. Int J Behav Nutr Phys Act, 2012; 9:68 [full text]
- Ekelund U, Luan JA, Sherar LB, Esliger DW, Grew P, Cooper A. Moderate to Vigorous Physical Activity and Sedentary Time and Cardiometabolic Risk Factors in Children and Adolescents. JAMA, 2012; 307: 704-712 [full text]
- Sherar L, Griew P, Esliger D, Cooper A, Ekelund U, Judge K, Riddoch C. International children’s accelerometry database (ICAD): Design and methods. BMC Public Health, 2011 [full text]
Studies that have contributed data
– NHANES (wave 2003/2004 and 2005/2006)
– Project TAAG (Trial of Activity for Adolescent Girls)
– CHAMPS US (Physical Activity in Pre-School Children)
– 1993 Pelotas Birth Cohort
– European Youth Heart Study (Norway, Portugal, Estonia and Denmark)
– PEACH Project (Personal and Environmental Association with Children’s Health)
– Project MAGIC (Movement and Activity Glasgow Intervention with Children’s Health)
– ALSPAC (Avon Longitudinal Study of Parents and Children)
– SPEEDY (Sport Physical Activity & Eating Behaviour: Environmental Determinants in Young People)
– CHAMPS UK (Children’s Health and Activity Monitoring Program)
– Belgium Pre-school Study
– Swiss Ballabeina Study
– Swiss Kinder-Sportstudie (KISS) Study
– Project CLAN (Children Living in Active Neighbourhoods)
– Project HEAPS (Healthy Eating And Play Study)