From the Guidelines
The criteria and classification of obesity in Japan and Asia-Oceania are increasingly recognized as more appropriate for Asian populations than Western standards, with a growing consensus on the use of lower BMI thresholds, such as BMI ≥ 23 kg/m², to define overweight and obesity in South and Southeast Asian countries. According to a recent study published in Obesity Reviews 1, a panel of South and Southeast Asian obesity specialists achieved consensus on treatment recommendations for individuals with BMI ≥ 23 kg/m² or waist circumference (WC) ≥ 80 cm (women) or ≥ 90 cm (men). This consensus reflects the growing recognition that Asian populations typically develop obesity-related health complications at lower BMI levels due to differences in body composition, with higher body fat percentages at the same BMI compared to Western populations.
The use of lower BMI thresholds to define obesity in Asian populations is supported by several studies, including a review of obesity in South and Southeast Asia published in Obesity Reviews 1, which highlights the need for country-specific approaches based on local health data and risk profiles. Another study published in the same journal 1 emphasizes the importance of recognizing obesity as a chronic disease that requires effective prevention and treatment, and notes that the definition and diagnostic criteria for obesity in adults and children are complex and multifaceted.
In terms of the classification of obesity, the Asia-Oceania Association for the Study of Obesity has established BMI cutoffs that define obesity at lower thresholds (BMI ≥ 25 kg/m² in Japan and ≥ 25-28 kg/m² in various Asian countries) compared to the WHO's global standard (BMI ≥ 30 kg/m²) 1. However, the implementation of these standards varies significantly across the region, with some countries maintaining their own specific criteria or continuing to use WHO standards.
A recent review of pharmacotherapies for managing obesity in South and Southeast Asia published in Obesity Reviews 1 notes that the choice of antiobesity medication should be based on obesity-related complications, severity of obesity, concurrent medications, and barriers to adherence, as well as the medications' efficacy, side effects, and contraindications. The review highlights the importance of considering the specific needs and circumstances of individual patients when selecting a treatment approach.
Overall, while there is growing recognition of the need for lower BMI thresholds to define obesity in Asian populations, the implementation of these standards varies significantly across the region, and further research is needed to develop country-specific approaches based on local health data and risk profiles. The use of lower BMI thresholds, such as BMI ≥ 23 kg/m², to define overweight and obesity in South and Southeast Asian countries is a key step towards improving the prevention and treatment of obesity in these populations.
From the Research
Criteria and Classification of Obesity in Japan and Asia-Oceania
The criteria and classification of obesity in Japan and Asia-Oceania are based on the definition of obesity as a body mass index (BMI) of ≥25 kg/m2, which is lower than the threshold in Western countries 2, 3, 4. This is because Japanese individuals tend to develop obesity-related health disorders at lower BMI levels.
Acceptance and Approval in Asian Countries
The acceptance and approval of these criteria in Asian countries are supported by studies that show the suitability of the WHO Regional Office for the Western Pacific Region (WPRO) criteria for Asians, which categorize overweight as a BMI of 23.0-24.9 and obese as a BMI of ≥25.0 5. These criteria are considered suitable for screening of overweight to prevent metabolic syndrome in elder Japanese workers.
Key Points
- The definition of obesity in Japan is a BMI of ≥25 kg/m2, which is lower than the threshold in Western countries 2, 3, 4.
- The WPRO criteria for Asians categorize overweight as a BMI of 23.0-24.9 and obese as a BMI of ≥25.0, which are considered suitable for screening of overweight to prevent metabolic syndrome in elder Japanese workers 5.
- Obesity in Japan is associated with a substantial burden, including higher total and medical costs, resource use, and hospitalization costs, as well as a considerable impact on physical and mental aspects of quality of life 6.
- The criteria and classification of obesity in Japan and Asia-Oceania are widely accepted and approved in Asian countries, as they are based on the specific health needs and risks of the Asian population.
Comparison with Western Countries
The criteria and classification of obesity in Japan and Asia-Oceania differ from those in Western countries, where obesity is typically defined as a BMI of ≥30 kg/m2. However, studies have shown that Japanese individuals are at risk of obesity-related health disorders even at lower BMI levels, making the lower threshold of ≥25 kg/m2 more suitable for the Asian population 2, 3, 4.