Kids bulge two sizes in 20 years

Children's average waistlines have expanded by about two clothing sizes in the past 20 years in what British scientists say is further proof of the growing problem of obesity in the young.

In a study of nearly 350 children aged 12 to 14, researchers at the East Leeds Primary Care Trust found waistlines were 4cm bigger than those of youngsters two decades ago.

New Zealand has no comparable figures, but health experts say children here are getting bigger - a major study published last year showed one third of children were overweight or obese.

Dr Mary Rudolph, who led the British study, said the results were particularly worrying because it was known that in adults an increase in fat around the waist was associated with cardio-vascular disease.

"It's a call for saying we really need to move fast to try to tackle this," she added.

The average waist size for 12- to 14-year-old girls in the study was 66cm, while in the 1980s it was 62cm.

In contrast, figures from the 2002 National Children's Nutrition Survey show the average waist measurement for New Zealand girls aged 11 to 14 was 75cm.

Maori and Pacific Island girls had higher averages of 77.9cm and 83cm, while European and other girls were lower at 73cm.

Otago University nutritionist Professor Jim Mann, chairman of the Children's Food and Nutrition Committee, said that while New Zealand children were undoubtedly getting bigger it would be dangerous to make comparisons with the British research as the groups were not part of the same standardised study.

He said no data from overseas was directly comparable to New Zealand.

New Zealand adult statistics were "broadly" comparable with other countries such as Britain, Australia, the US and Canada and Professor Mann believed that was likely to be the case with children.

While scientists use body mass index (BMI) to measure overweight and obesity, research has shown that where fat accumulates is an important indicator of health risks.

BMI is calculated by dividing weight in kilograms by height in metres squared. A BMI of 30 or more is considered obese.

Waist circumference is important because a build-up of fat around the abdomen is more dangerous than on the thighs or the bottom.

Obesity is also linked to diabetes, a disease experts predict will affect 3 million people in Britain and 221 million worldwide by 2010.

Childhood obesity has risen dramatically in most countries in Europe and in the US due to a decrease in physical activity and changes in eating habits.

Nearly 16 per cent of children aged 6 to 16 in Britain are obese.

Health experts have warned that rates could soar higher if strategies are not developed to tackle the problem.

The scientists, who reported their findings in the journal Archives of Disease in Childhood, compared the height, weight, BMI and waist measurements of children from 18 schools in 1996-1998 and again in 2001.

Four per cent of girls in the study were obese in 1996 and 2001 but the number of obese boys rose from zero to 3 per cent over the same time.

- Reuters, Rebecca Walsh