Background/Aim Physical inactivity (PIA) is a growing global health problem and evidence suggests that PIA is a key driver for cardiovascular and chronic diseases. Recent data from South Africa revealed that only about half of the children achieved recommended daily physical activity (PA) levels. Assessing the intensity of PA in children from low socioeconomic communities in low-income and middle-income countries is important to estimate the extent of cardiovascular risk and overall impact on health.
Methods We conducted a cross-sectional survey in eight quintile 3 primary schools in disadvantaged communities in the Port Elizabeth region, South Africa. Children aged 10–15 years were subjected to PA, blood pressure, cholesterol, blood glucose and skinfold thickness assessments. Cardiovascular risk markers were converted into standardised z-scores and summed, to obtain a clustered cardiovascular risk score.
Results Overall, 650 children had complete data records. 40.8% of the children did not meet recommended PA levels (ie, logged <60 min of moderate-to-vigorous physical activity (MVPA) per day). If quartiles were developed based on children’s cardiorespiratory fitness (CRF) and MVPA levels, a significant difference was found in clustered cardiovascular risk among children in the highest versus lowest fitness (p<0.001) or MVPA (p<0.001) quartiles.
Conclusions CRF and objectively assessed PA are closely linked with children’s clustered cardiovascular risk. Given that 4 out of 10 South African schoolchildren from marginalised communities do not meet international PA recommendations, efforts should be made to ensure that promoting a physically active lifestyle is recognised as an important educational goal in primary schools.
Trial registration numbers ISRCTN68411960 and H14-HEA-HMS-002.
- Non-communicable disease
- Physical activity
- Risk factor
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Contributors IM, CW, RDR, HS, PS, NP-H, JU, UP and MG designed the study, established the methods and wrote the original study protocol. All other authors contributed to the development of the study protocol. IM, CW, RDR, LA, JD, SG, NJ, SN, DS, UP and MG conducted the fieldwork of the study. IM, LA, JD, SG, NJ, SN and DS managed data entry, cleaning and preparation of the database. Statistical analysis was done by MG. IM wrote the first draft of the manuscript with support of MG. CW, RDR, AA, LA, JD, SG, NJ, SN, SDR, DS, HS, PS, CW, NP-H, JU and UP provided comments on the drafts and have read and approved the final version of the manuscript prior to submission. IM and MG are guarantors of the paper.
Funding The cross-sectional study presented here was financially supported by the Novartis Foundation (Basel, Switzerland). The funder had no role in study design, data collection, data analysis or data interpretation, nor the decision to submit the paper for publication.
Competing interests The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication. All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf, indicating no support from any other organisation for the submitted work, no financial relationships with any other organisations that might have an interest in the submitted work in the previous three years, and no other relationships or activities that could appear to have influenced the submitted work. AA and SDR are employees of Novartis Foundation (Basel, Switzerland); ChrW is an employee of Novartis International AG (Basel, Switzerland). All other authors declare no financial competing interests.
Ethics approval This study was approved by the ethics committees of Northwest and Central Switzerland (EKNZ; reference no. 2014-179, approval date: June 17, 2014), the Nelson Mandela University (NMU; study number H14-HEA-HMS-002, approval date: July 4, 2014), the Eastern Cape Department of Education (approval date: August 3, 2014) and the Eastern Cape Department of Health (approval date: November 7, 2014). The study is registered at ISRCTN registry under controlled-trials.com (identifier: ISRCTN68411960, registration date: October 1, 2014).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement The raw datasets are available from the corresponding author on reasonable request.
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