Health and social scientists need to weigh in

To the Editor: In South Africa, a substantial segment of the population is overweight.¹ In 2000, non-communicable diseases (NCDs) accounted for 37% of deaths among adults² and this figure is rising alongside expanding waistlines. Overweight children are twice as likely to have elevated blood pressure, 13 times more likely to have elevated insulin levels, and 7 times more likely to have higher triglyceride levels.³ This noxious cocktail of risk factors predisposes overweight young people to develop NCDs as adults.

The Birth to Twenty (Bt20) cohort⁴ found that more than 70% of black female caregivers were overweight, and a staggering two-thirds of these adults were obese. Also, 9% of black female adolescents at age 13 were overweight and an additional 6% were obese.

We need evidence-based research that tackles the social epidemiology of obesity. There is no published South African research incorporating joint insights from both social and health science theory. We need to move towards a more comprehensive local model of obesity causation - properties of food (portion size, energy density, sugar-sweetened beverage intake); socioeconomic factors (transportation, food pricing and availability of food choices, sedentary work, child care arrangements); home-environmental influences (parental role modelling, family meals, crèche, school meals, TV viewing); and eating behaviours (snacking).

Consider this Bt20 scenario: an adolescent living in Soweto uses public transport to school as her mother can’t afford a bicycle and it’s not safe or ‘cool’ to ride. She has R10 for lunch, which she spends on a sweetened beverage and a packet of potato chips. There are few sports facilities at school and physical education is not promoted, and consequently she doesn’t participate in any school sport. At home she watches the afternoon ‘soaps’ and snacks on sandwiches. She strolls down the street to meet up with her friends, but engages in little other home-based physical activity. Her mother, who is obese and has high blood pressure, gets little exercise other than walking to and from the taxi rank and local grocery store. With her modest income she prepares a usual dinner - stiff maize-meal with fatty bones fried in oil and made into gravy. After dinner she has her fourth cup of coffee for the day with 3 teaspoons of sugar and watches some television while doing the ironing.

This may seem over-simplistic, but this daily scenario is commonplace and is placing young urban adolescents, especially girls, at high risk of developing obesity-related diseases. If social and health scientists do not work together to understand and combat the complex aetiology of obesity by imparting information to health professionals, educators and parents, then the South African NCD burden will increase unabated.