UC Davis

Purpose

Scant research has investigated whether health promotion interventions have sustained effects in increasing physical activity and healthful diet among adolescents in sub-Saharan Africa, which is experiencing an epidemiological transition from infectious diseases to noncommunicable diseases as leading causes of mortality. We examined whether an intervention increased adherence to 5-a-day diet and physical activity guidelines during a 54-month postintervention period among South African adolescents and whether its effects weakened at long-term (42 and 54 months postintervention) compared with short-term (3, 6, and 12 months postintervention) follow-up.

Methods

We randomized 18 randomly selected schools serving grade 6 learners (mean age = 12.6) in a township and a semirural area in Eastern Cape Province, South Africa, to one of the two 12-hour interventions: health promotion, targeting healthful diet and physical activity; attention-matched control, targeting sexual risk behaviors. We tested the intervention's effects on adherence to 5-a-day diet and physical activity guidelines using generalized estimating equations logistic regression models adjusting for baseline behavior and clustering within schools.

Results

Health promotion intervention participants had higher odds of meeting 5-a-day diet and physical activity guidelines than control participants. The effect on 5-a-day diet did not weaken at long-term compared with short-term follow-up, but the effect on physical activity guidelines was weaker at long-term follow-up, mainly because of a reduced effect on muscle-strengthening physical activity. The intervention also increased health promotion attitude and intention and health knowledge and reduced binge drinking compared with the control group.

Conclusions

A 12-hour intervention in grade 6 shows promise in increasing self-reported adherence to healthful diet and physical activity guidelines during a 4.5-year postintervention period among South African adolescents.