Scientists appear to have discovered why people who are apple shaped are at an increased risk of developing kidney disease.

Apple-shaped bodies are those in which fat is mostly concentrated in the abdominal region. People who are apple shaped are more likely to develop kidney disease than pear-shaped people, but until now, it was unclear why.

Dutch scientists decided to investigate this further. They looked at possible links between kidney health and waist-to-hip ratios - which show how central body fat is distributed - in 315 healthy women of normal weight.

They found that a higher waist-to-hip ratio, like that found in apple-shaped people, was linked to lower kidney function, lower kidney blood flow and higher blood pressure within the kidneys.

"We found that apple-shaped persons, even if totally healthy and with a normal blood pressure, have an elevated blood pressure in their kidneys. When they are also overweight or obese, this is even worse," the scientists explained.

They believe that this high blood pressure within the kidneys of people who are apple shaped is responsible for the increased risk of kidney disease seen in this group.

They noted that previous research has indicated that this high blood pressure within the kidneys can be treated with certain drugs or by restricting salt intake.

"Our current data suggest that such interventions could be particularly useful in subjects with a central body fat distribution," they added.

Details of these findings are published in the Journal of the American Society of Nephrology.