Deriving ethnic-specific BMI cutoff points for assessing diabetes risk.

Area of Science:

• Public Health
• Epidemiology
• Metabolic Disease Research

Background:

• The universal definition of obesity (body mass index [BMI] ≥ 30 kg/m²) is primarily based on white populations.
• Its applicability to nonwhite populations, who may have different body compositions and metabolic profiles, has been questioned.
• Obesity is a significant risk factor for type 2 diabetes.

Purpose of the Study:

• To compare diabetes incidence rates across different ethnic groups (white, South Asian, Chinese, black).
• To identify ethnic-specific body mass index (BMI) cutoff values for assessing diabetes risk.
• To evaluate the appropriateness of the current obesity definition in diverse populations.

Main Methods:

• A multiethnic cohort study involving 59,824 non-diabetic adults aged 30 years and older in Ontario, Canada.
• Data sourced from Statistics Canada's population health surveys.
• Follow-up for up to 12.8 years for diabetes incidence using linked health administrative databases.

Main Results:

• Diabetes risk was significantly higher in South Asian (HR 3.40), black (HR 1.99), and Chinese (HR 1.87) individuals compared to white individuals, after adjusting for confounders.
• The median age of diabetes diagnosis was lower in South Asian (49 years), Chinese (55 years), and black (57 years) individuals compared to white individuals (58 years).
• Equivalent BMI cutoffs for a diabetes incidence rate similar to a BMI of 30 kg/m² in whites were 24 kg/m² for South Asians, 25 kg/m² for Chinese, and 26 kg/m² for black individuals.

Conclusions:

• South Asian, Chinese, and black populations exhibit higher diabetes incidence rates, earlier age of onset, and lower BMI ranges compared to white populations.
• Current obesity targets for ideal body weight need to be lowered for nonwhite populations.
• Ethnically tailored prevention strategies are crucial for managing diabetes risk in diverse ethnic groups.