New research suggests the size of your waist can predict your chance of death.

As the rate of obesity in many countries continues to rise, health officials worry about the expanding waistlines of their citizens.

And it turns out there's reason to worry. New research suggests the size of your waist can predict your chance of death.  

Eric Jacobs and his colleagues from the American Cancer Society asked about  100 000 older Americans - men and women, rich and poor, smokers and non-smokers - to measure their waistlines intermittently over a nine-year period.

Jacobs says there's something about the fat that gathers near the waist that makes it particularly harmful.

"We know that deep abdominal fat has been linked with higher blood levels of cholesterol and insulin," he says. "Also inflammation-related proteins that have been linked to cardiovascular disease."

During the nine years they followed their subjects, 9300 of the men and 5300 of the women died.  Jacobs and his colleagues reviewed the information they had about them: their weight, height and their waist size.

"And what we saw was that the bigger the waist size, the greater the risk of death," Jacobs says. "In fact, those with the very biggest waist sizes had about twice the risk of dying as those with the smallest waists."

Jacobs says the deaths were from all causes, not just cancer, or heart disease or lung disease. Simply having a larger waist made it more probable that someone would die sooner. And in Jacobs' analysis, it turns out it didn't matter how much people weighed, either, only their waist size mattered.

"For example, among women with weights that were considered normal for their height, the risk of dying increased about 25 per cent for each additional four inches (10cm) of waist size," Jacobs says.

He explains someone who's sedentary and someone who's active could weigh the same, but the person who didn't do much exercise would probably have more abdominal fat. The active person's weight might come more from muscle which is denser than fat  - so, it adds weight without adding inches.

"So even if your weight is considered normal for your height, even if you haven't noticed a big weight gain, if your waist size is starting to increase, if you are having to move into a bigger pants size, that's a signal that you need to start eating better and exercising more," Jacobs says.

And he says there's really no short cut.  There's no proven method to lose so-called 'belly fat.'  Diet and exercise are really the only ways to shrink waist size.