Teenage years are often seen as a time of strength and vitality when lifelong habits for good health begin to take shape. But new research from the University of the Western Cape (UWC) suggests this picture may be shifting, with a worrying number of adolescents in Cape Town showing early signs of metabolic syndrome, a cluster of interrelated conditions that increases the risk of heart disease and type 2 diabetes later in life. This comes as World Obesity Day is being commemorated across the globe.
Metabolic syndrome, or MetS, includes conditions such as abdominal obesity, high blood pressure, raised blood sugar and abnormal cholesterol levels. While this condition is well studied in adults, less is known about its prevalence among teenagers in sub-Saharan Africa. To address this gap, researchers led by PhD student Annalie Wentzel from the School of Public Health assessed about 500 teenagers, aged 13 to 18, mostly from lower to middle-income schools and households in Cape Town.
Other authors on the study include Prof Zandile Mchiza and Dr Kim Anh Nguyen from the South African Medical Research Council, Prof Naomi Levitt from the Chronic Disease Initiative for Africa at the University of Cape Town, and Dr Peter von Philipsborn, Chair of Public Health Nutrition at the University of Bayreuth in Germany.
Researchers assessed the prevalence of MetS among adolescents using five international guidelines and compared how closely these guidelines aligned with one another. They measured factors such as blood pressure and fasting blood sugar, while considering lifestyle habits, including physical activity and screen time.
The results showed that four of the guidelines produced very similar findings, with between 4.7% and 5.7% of adolescents found to have metabolic syndrome. However, one guideline called de Ferranti, stood out, identifying a much higher rate of almost 18%. Large waistline and high blood pressure were the most common risk factors for metabolic syndrome, irrespective of the guidelines used. The study found that girls, particularly black African, were more likely than boys to have metabolic syndrome under most diagnostic criteria.
This higher risk among females was mainly associated with greater abdominal obesity, higher body mass index, and elevated blood pressure. This increased risk in girls is shaped by a mix of biological, behavioural and social factors, including the early onset of puberty in girls, which is associated with natural increases in body fat and changes in cholesterol levels during adolescence.
“Cultural norms in many South African settings that favour a larger female body size, or view weight gain as a sign of health or maturity, may reinforce acceptance of higher adiposity levels and normalise overweight,” researchers noted.
Living conditions and school backgrounds played a role, with adolescents living in informal housing having significantly higher rates of metabolic syndrome than those living in brick houses – suggesting a link between informal housing and metabolic disorders.
Furthermore, they have noted that the high levels of elevated blood pressure, abdominal obesity and unhealthy cholesterol levels, especially among girls, highlight the urgent need for early and targeted health interventions. The findings also stress the importance of using appropriate health screening tools that account for differences between boys and girls and across populations.
