London: Obesity is increasing more rapidly in the world’s rural areas than in cities, according to a study of global trends in body-mass index (BMI). The study, published in the journal Nature, analysed the height and weight data of over 112 million adults across urban and rural areas of 200 countries and territories between 1985 and 2017. Height and weight can be used to calculate BMI, an internationally recognised scale which tells us whether an individual has a healthy weight for their height, said researchers led by Imperial College London in the UK.
The study found that from 1985 to 2017, BMI rose by an average of two kilogrammes per square metre (kg/m2) in women and 2.2 kg/m2 in men globally, equivalent to each person becoming five to six kg heavier. Over half of the global rise over these 33 years was due to increases in BMI in rural areas. In some low- and middle-income countries, rural areas were responsible for over 80 per cent of the increase. The team found that since 1985, average BMI in rural areas has increased by 2.1 kg/m2 in both women and men.
However, in cities, the increase was 1.3 kg/m2 and 1.6 kg/m2 in women and men respectively. These trends have led to striking changes in the geography of BMI over the three decades, researchers said. In 1985, urban men and women in over three quarters of the countries had a higher BMI than their rural counterparts, they said. Over time, the gap between urban and rural BMI in many of these countries shrank or even reversed. “The results of this massive global study overturn commonly held perceptions that more people living in cities is the main cause of the global rise in obesity,” said Professor Majid Ezzati of Imperial’s School of Public Health.
“This means that we need to rethink how we tackle this global health problem,” Ezzati said. The team found important differences between high-, middle-, and low-income countries. In high-income countries, the study showed that BMI has been generally higher in rural areas since 1985, especially for women. The researchers suggest this is due to the disadvantages experienced by those living outside cities: lower income and education, limited availability and higher price of healthy foods, and fewer leisure and sports facilities. “Discussions around public health tend to focus more on the negative aspects of living in cities,” said Ezzati.