Female sex and higher education linked to escalating prevalence of obesity and overweight in Africa

Female sex and higher education are significantly linked to the escalating prevalence of obesity and overweight in Africa, finds one of the largest and most detailed analyses of body weight trends in the region, published in the open access journal BMJ Global Health.

Women’s odds of obesity in Africa are 5 times greater than those of men’s, while obesity is 3 times more likely in those with tertiary level education than in those with lower levels, the findings indicate.

The global prevalence of overweight and obesity has more than doubled over the past 4 decades. In 2022, 2.5 billion adults were overweight, representing 43% of all the world’s adults, and 890 million were living with obesity, note the researchers.

While recent research suggests that the rate of increase in overweight and obesity may be slowing in high income countries, it seems to be speeding up in low- and middle-income countries, where around two thirds of those living with obesity now reside, they explain.

Africa is particularly vulnerable because of its fragile healthcare systems, limited resources, socioeconomic complexities, urbanisation and sparse public health policies, they add.

The researchers wanted to explore the extent of overweight and obesity in Africa, and capture 20 year trends (2003-22).

They analysed data from 54 nationally and regionally representative STEPS (STEPwise approach to non-communicable disease risk factor surveillance) surveys carried out between 2003 and 2022 for 36 of the 47 countries in the World Health Organization (WHO) Africa region—representing three-quarters of the total population and 156 million adults.

Underweight was defined as a BMI of less than 18.5, overweight as a BMI of between 25 and 29.9, and obesity as a BMI of 30 or more.

The surveys captured weekly physical activity levels from low (below the recommended weekly tally) to high (above this) and daily portions of fruits and vegetables consumed (from 0-1 to 4-5).

In all, data were obtained for 198,901 adults with an average age of 36; half were women. Of the countries included in the analysis, 13 were in West Africa, 9 in East Africa, 5 in Southern Africa, 8 in Central Africa and 1 in North Africa (Algeria).

The analysis revealed that the age standardised and weighted prevalence of underweight, overweight, and obesity was 11.5%, just under 18%, and 9%, respectively.

Twenty year trends showed a significant increase in the overall prevalence of obesity from nearly 15.5% in 2003 to nearly 17% in 2022; of underweight from 12% to just under 13%; and a levelling out in the prevalence of overweight (around 18% between 2003 and 2022).

The prevalence of overweight and obesity was, respectively, just under 18% and 9% higher in women (21% and nearly 13.5%) than in men (15% and just over 4.5%).

After adjusting for potentially influential factors, female sex, older age, higher education level, physical inactivity and poor diet were all associated with overweight or obesity.

The odds of overweight and obesity were, respectively, twice as high and almost 5 times as high, in women as they were in men. And those educated to tertiary level were twice as likely to be overweight and nearly 4 times as likely to be obese than those educated to lower levels.

“Taken together, these findings underscore the need for targeted public health interventions that consider the unique socio-cultural and economic contexts affecting women in the WHO African region,” say the researchers.

“Also, the results raise the point that education and awareness campaigns should not solely target individuals with lower education levels, as those with higher education may also require information and support,” they add.

“The present study further underscores the dual burden of malnutrition in the Africa region, showing significant increased trends in both obesity and underweight,” they continue.

The researchers acknowledge various limitations to their findings including that the WHO Africa region does not cover all of the continent, and that no data were available from South Africa, a country with one of the highest rates of overweight and obesity.

Nor did they study potentially influential factors, including cultural norms, accessibility to preventive healthcare, commercial factors, and household income. And the survey focused only on 18–69 year olds, excluding children and older adults.

But they nevertheless conclude: “These findings support the urgent need to intensify preventive health policies and programmes in the WHO African region.”