Image caption Obesity rates have risen worldwide

One in 10 of the world's adults is obese, according to a joint UK-US study published in The Lancet

Imperial College London and Harvard researchers studied body mass index (BMI), cholesterol and high blood pressure data from 1980 to 2008.

High blood pressure and cholesterol fell in many developed countries while obesity generally rose worldwide.

Men in the UK have the sixth highest BMI in Europe while UK women have the ninth highest BMI in Europe.

Obesity, cholesterol and high blood pressure are all risk factors for heart disease.

In 2008, 9.8% of men and 13.8% of women in the world were obese - they had a BMI above 30kg/m2.

This is compared with 4.8% for men and 7.9% for women in 1980.

What is BMI - Body Mass Index? BMI is measured by taking a person's weight in kg and dividing by the square of their height in metres. A BMI of 18.5 to 25 is considered healthy, over 25 is deemed overweight and greater than 30 is obese.

Pacific island nations had the highest average BMI in the world at 34-35kg/m2.

This was up to 70% higher than some countries in south-east Asia and sub-Saharan Africa.

In common with the rest of the world, BMI rose among most high-income countries.

Among those countries, BMI rose the most in the USA between 1980 and 2008, followed by New Zealand and Australia for women and the UK and Australia for men.

Western countries bucking the BMI trend Some countries in Western Europe succeeded in stabilising their BMI levels. There was virtually no rise in women's BMI in Belgium, Finland, France, Italy and Switzerland. Italy and Switzerland also saw the smallest increases in male BMI across the period.

However, while obesity rates in many countries across the world increased, many higher income countries succeeded in reducing both high blood pressure and cholesterol.

Large reductions in high blood pressure were seen, for example, in women in Australasia and men in North America.

Overall, the percentage of people in the world with high blood pressure fell slightly.

However, for UK adults, blood pressure fell by less that most other European high-income countries.

Blood pressure levels were highest in the Baltic and East and West African countries. Systolic blood pressure levels reached 135 mmHg for women and 138 mmHg for men in those areas.

UK BMI, Blood Pressure and Cholesterol Levels, 1980 - 2008 BMI LEVELS

BMI levels for UK men were 24.7 in 1980, rising to 27.4 in 2008.

BMI levels for women were 24.2 in 1980 and 26.9 in 2008.

BLOOD PRESSURE LEVELS

Systolic Blood Pressure levels were measured - that's the pressure while the heart is pumping blood around. It is measured in millimetres of mercury.

In 1980 men had blood pressure of 136.5 mmHg falling to 131.2 in 2008.

In 1980 women had blood pressure levels of 131.0 falling to 124.1 in 2008.

CHOLESTEROL LEVELS

Cholesterol blood levels were measured in millimoles per litre (mmol/L).

In 1980 men's cholesterol blood levels were 6.2mmol/L, falling to 5.4mmol/L in 2008.

In 1980 women's cholesterol blood levels were 6.2mmol/L falling to 5.4mmol/L in 2008

Average levels of total blood cholesterol fell across many Western countries including North America, Australasia and Europe.

In the UK men and women both showed one of the largest drops in cholesterol in high income countries. However the UK's cholesterol is still ninth highest in the world.

Conversely, blood cholesterol levels increased in the East, south-east Asia and the Pacific region.

Professor Majid Ezzati, a lead author of the study welcomed the improved results in high blood pressure and cholesterol in higher income countries, saying: "It's heartening that many countries have successfully reduced blood pressure and cholesterol despite rising BMI.

"Improved screening and treatment probably helped to lower these risk factors in high-income countries, as did using less salt and healthier, unsaturated fats."

The British Heart Foundation (BHF) said the increasing obesity rates were "striking."

However their associate medical director, Dr Mike Knapton welcomed the progress in high blood pressure and cholesterol saying; "It's not all bad news.

"We've seen marked progress in reducing blood pressure and cholesterol across the developed world, proving lifestyle and medical interventions can work."