While high-income countries have significantly reduced blood pressure and cholesterol levels since 1980, the prevalence of obesity has almost doubled. Three research studies published in the Feb. 3 issue of the Lancet, show that these levels vary greatly by country and region.

The studies, written by Majid Ezzati, MD, of the Imperial College in London, and colleagues outline the trends of body mass index (BMI), systolic blood pressure (BP) and cholesterol levels since 1980 in almost 3 million participants in 199 countries.

The researchers used a Bayesian hierarchical model to estimate mean BMI, BP and cholesterol levels by age, country and year.

In 2008, 9.8 percent of the world’s male population were obese, as were 13.8 percent of women. In 1980, these rates were 4.8 percent and 7.9 percent.

The researchers found that worldwide mean BMI increased by 0.4 kg/m² per decade for men and 0.5 kg/m² for women. Changes in BMI for women decreased in 19 countries while male BMI increased in all but eight countries. Male and female BMIs in 2008 were highest in Oceania countries, reaching 33.9 kg/m² for men and 35 kg/m² in Nauru.

BMI was highest in the U.S., while female BMI was lowest in Bangladesh and the Democratic Republic of the Congo for men. Lastly, the researchers reported that in 2008, 1.46 billion adults worldwide had a BMI that was equal to or greater than 25 kg/m². Of these, 205 million men and 297 million women were obese.

As for cholesterol levels, the researchers reported that the mean total cholesterol worldwide was 4.64 mmol/L for men and 4.76 mmol/L for women. The mean total levels of cholesterol saw a small change between 1980 and 2008, only falling by less than 0.1 mmol/L in both men and women. In high-income regions including Australasia, North America and western, central and eastern Europe, these levels fell by almost 0.2 mmol/L per decade for both sexes.

On the contrary, cholesterol levels for men and women increased by 0.08 mmol/L and 0.09 mmol/L, respectively, in east and southeast Asia and Pacific. In 2008, the researchers reported that cholesterol was highest in high-income regions including Australasia, North America and western Europe—5.24 mmol/L for men and 5.23 mmol/L for women. Cholesterol was lowest in sub-Saharan Africa at 4.08 mmol/L for men and 4.27 mmol/L for women.

Lastly, in the blood pressure study, the researchers found that systolic BP levels globally were 128.1 mmHg for men and 124.4 mmHg in women. Between 1980 and 2008, these numbers decreased by 0.8 mmHg in men and 1 mmHg in women.

While female BP dropped by 3.5 mmHg or more in western Europe and Australasia, male BP dropped more significantly in North America, by 2.8 mmHg per decade. And while female BP was highest in regions of eastern and western Africa, male BP was highest in the Baltic and eastern and western African countries, while western Europe saw the highest rates of BP for both sexes.

"Our results show that overweight and obesity, high blood pressure and high cholesterol are no longer western problems or problems of wealthy nations. Their presence has shifted towards low and middle income countries, making them global problems,” Ezzati and colleagues wrote.

Ezzati et al said that implementing policies that would focus on healthier diets, including lowering salt intakes, could improve detection and control of BMI, BP and cholesterol levels.

In an accompanying editorial, Drs. Salim Yusuf and Sonia S. Anand of McMaster University in Hamilton, Ontario, wrote that "[f]ocusing on controlling these three risk factors [blood pressure, total cholesterol and smoking] will rapidly and to a large extent reduce cardiovascular disease globally within a few years, while we continue our efforts to stem and ultimately reverse the tide of obesity, which will need more prolonged and societal-based interventions over decades."

The studies were funded by the Bill & Melinda Gates Foundation and the World Health Organization.