BMJ Open 2:e000362 doi:10.1136/bmjopen-2011-000362
  • Public health
    • Research

Cohort profile: Ho Chi Minh City Youth Cohort—changes in diet, physical activity, sedentary behaviour and relationship with overweight/obesity in adolescents

  1. Michael John Dibley2
  1. 1Department of Community Health, Pham Ngoc Thach University of Medicine, Ho Chi Minh City, Vietnam
  2. 2Sydney School of Public Health, Sydney Medical School, The University of Sydney, Sydney, Australia
  1. Correspondence to Dr Trang Doan Hanh Nguyen Hoang; nguyenhoang_doantrang{at}
  • Received 30 August 2011
  • Accepted 24 January 2012
  • Published 15 February 2012


Objectives The Ho Chi Minh Youth cohort study aimed to assess the change in nutritional status; indicators of adiposity; diet; physical activity and sedentary behaviours; home, neighbourhood and school microenvironments and their complex relationships in adolescents in urban areas of Ho Chi Minh City.

Design Prospective 5-year cohort.

Setting Systematic random sampling was used to select 18 schools in urban districts.

Participants Children were followed up over 5 years with an assessment in each year. Consent, from both adolescents and their parents, was required. At baseline, 759 students were recruited into the cohort, and of these students, 740 remained in the cohort for the first round, 712 for the second round, 630 for the third round and 585 for the last round of follow-up.

Primary and secondary outcome measures Anthropometric measurements were taken using established guidelines. Six main groups of exposure factors including dietary intake and behaviours, physical activity and sedentary behaviours, family social and physical environment, school environment, socioeconomic status and parental characteristics were measured.

Results Retention rate was high (77%). Within 5-year period, the prevalence of combined overweight and obesity using International Obesity Task Force cut-off values increased from 14.2% to 21.8%. Time spent on physical activity decreased significantly in the 5-year period from 87 to 50 min/day. Time spent on sedentary behaviours increased in the 5-year period from 512 to 600 min/day.

Conclusions The complete data analysis of this cohort study will allow a full exploration of the role of environmental and lifestyle behaviours on adolescent overweight and obesity and also identify the factors most strongly associated with excess weight gain and the appearance of overweight and obesity in different age groups of adolescents from this large city in Vietnam.


  • To cite: Trang Nguyen HHD, Hong TK, Dibley MJ. Cohort profile: Ho Chi Minh City Youth Cohort—changes in diet, physical activity, sedentary behaviour and relationship with overweight/obesity in adolescents. BMJ Open 2012;2:e000362. doi:10.1136/bmjopen-2011-000362

  • Contributors TNHHD, HKT and MJD all contributed to the conceptualisation, design and management of the study and all revised this manuscript critically. All authors gave final approval of the version to be published.

  • Funding This work was supported by the Nestlé Foundation grant (P673-1773).

  • Competing interests None.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Access to the data set is available from the corresponding author (nguyenhoang_doantrang{at} or the principle investigator (hongutc{at} in STATA format for academic researchers interested in undertaking a formally agreed collaborative research project.

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