Last Updated: 2007-10-22 16:13:43 -0400 (Reuters Health)

NEW YORK (Reuters Health) – The increasing prevalence of overweight and obesity has left few parts of the world unaffected, according to results of the International Day for Evaluation of Abdominal Obesity (IDEA) study.

IDEA study participants were primary care physicians in 63 countries representing five continents who recruited 168,159 consecutive patients aged 18 to 80 years, on two pre-specified half days.

Reporting in the October 23rd issue of Circulation, the investigators show that waist circumference is a more accurate clinical marker for risk of cardiovascular disease (CVD) and diabetes than is body mass index (BMI). Increased waist circumference denotes risk "even in patients with normal weight."

Lead author Dr. Beverley Balkau, director of research at INSERM in Villejuif, France and her associates report that the frequency of overweight (BMI 25 to 30) was "remarkably similar across region," affecting 40% of men and 30% of women.

While roughly one out of four adults were obese (BMI > 30), the prevalence varied widely by region, with low rates in southern and eastern Asia (approximately 7%) and high rates in the Middle East and some regions of Africa (approximately 39%).

Even after accounting for BMI, a high waist circumference was associated with prevalent cardiovascular disease and diabetes.

The authors analyzed morbidity based on quintiles of waist circumference. Among men in the highest quintile (107 cm or higher), the prevalence of CVD and diabetes were 2 and 3-fold higher, respectively, compared with those in the lowest quintile (< 84 cm).

Similar comparisons among women in the highest and lowest quintiles (101 cm or greater versus < 76 cm) showed that the odds ratios were 2.6 for CVD and nearly 6 for diabetes.

"Our findings support the need for worldwide population-based initiatives to target adiposity," Dr. Balkau and associates state, emphasizing that interventions should begin early in life.

Circulation 2007;116.