Worldwide adult obesity prevalence has doubled since 1980

Three studies of global health trends recently published in The Lancet suggest the worldwide prevalence of obesity has doubled since 1980, but that average blood pressure and cholesterol levels have decreased in wealthy Western countries.

The three studies were conducted by the Global Burden of Metabolic Risk Factors of Chronic Diseases Collaborating Group. To calculate their totals, the authors culled health data of adults 25 years and older from published and unpublished health examination surveys and epidemiological studies across 199 countries and territories. To define their trends, they compared data from 2008 to data from 1980.

According to their findings, more than one in 10 of the world’s adults was obese in 2008, with women more likely to be obese than men. Obesity was defined as having a BMI above 30 kg/m². Overall, the study estimated that more than half a billion adults worldwide are obese.

The study of systolic blood pressure (SBP) observed a slight decrease in the percentage of the world’s population with uncontrolled hypertension, defined as SBP higher than 140 mm Hg or diastolic BP higher than 90 mm Hg. High-income countries achieved larger reductions in uncontrolled hypertension, with men in North America faring the best by losing 2.8 mm Hg in SBP per decade on average. Increases in SPB in both sexes were observed in Oceania, east Africa, and south and Southeast Asia.

The final study reported that the 2008 age-standardized mean cholesterol level worldwide was 4.6 mmol/L for men and 4.76 mmol/L for women. The researchers also found average cholesterol levels decreasing by 0.2 mmol/L per decade in North America, Australia and Europe. Cholesterol increases were observed in east and Southeast Asia and the Pacific region (0.8 mmol/L per decade for men and 0.9 mmol/L per decade for women).

"Our results show that overweight and obesity, high BP 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,” author Majid Ezzati, PhD, Imperial College London, United Kingdom, said in a press release.

"The findings are an opportunity to implement policies that lead to healthier diets, especially lower salt intake, at all levels of economic development, as well as looking at how we improve detection and control through the primary healthcare system.,” Ezzati continued. “Policies and targets for cardiovascular risk factors should get special attention at the High-level Meeting of the United Nations General Assembly on Non-Communicable Diseases in September 2011."

Other global trends observed by the studies include:

BMI:

In 2008, 9.8% of men and 13.8% of women in the world were obese, defined as having a BMI above 30 kg/m². This compares to 4.8% for men and 7.9% for women in 1980.
Pacific island nations have the highest average BMI in the world.
Among high income countries, USA has the single highest BMI. Japan has the lowest BMI.
Among high-income countries, between 1980 and 2008, BMI rose the most in USA, by more than 1 kg/m² per decade. Women had virtually no rise in BMI in Belgium, Finland, France and Switzerland. Italy was the only high-income European country in which female BMI may have fallen from 1980 to 2008. Italy and Switzerland also saw one the smallest increases in male BMI.

Blood pressure:

The USA, South Korea, Cambodia, Australia and Canada had some of the lowest blood pressures for both men and women, below 120 mmHg for women and below 125 mmHg for men.
Systolic blood pressure levels are highest in Baltic and East and West African countries, reaching 135 mmHg for women and 138 mmHg for men.
Among high income countries, Portugal, Finland and Norway have the highest blood pressure.
Men had higher blood pressure than women in most world regions.

Cholesterol:

Among western high-income countries, Greece has the lowest cholesterol for both men and women, defined as below 5 mmol/L. USA, Canada, and Sweden also had low cholesterol.
Western European countries like Greenland, Iceland, Andorra, and Germany have the highest cholesterol levels in the world, with mean serum total cholesterols of around 5.5 mmol/L.
African countries have the lowest cholesterol, some as low as 4 mmol/L.
Uniquely among high-income countries, Japan has seen its average cholesterol in men and women rise from a low starting point in 1980 to the levels seen in Western Europe in 2008. Singapore and China also experienced increases. These changes are at least partly due to changes in diet, including increasing intake of animal products and fats.

For more information:

Finucane M. Lancet. 2011; doi:10.1016/S0140-6736(10)62037-5.
Danaei G. Lancet. 2011; doi:10.1016/S0140-6736(10)62036-3.
Farzadfar F. Lancet. 2011; doi:10.1016/S0140-6736(10)62038-7.

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