Anthropometric assessment - waist-to-hip ratio (WHR)

Definition

Waist-to-hip ratio (waist circumference divided by hip circumference) estimates central/visceral adiposity distribution - a better predictor of cardiometabolic risk than BMI alone, since visceral fat specifically (rather than total body fat) drives much of the metabolic risk associated with excess adiposity
Increasingly used alongside or instead of BMI in cardiometabolic risk assessment, given growing recognition that fat distribution (not just total quantity) matters for health risk

Visceral (central/abdominal) fat is metabolically more active and more strongly associated with insulin resistance, dyslipidaemia, and cardiovascular risk than subcutaneous fat elsewhere on the body - explaining why two individuals with identical BMI but different fat distribution patterns can have substantially different metabolic risk profiles

An elevated waist-to-hip ratio (thresholds vary by sex and population, generally higher risk above approximately 0.90 in men and 0.85 in women) identifies central adiposity-associated risk even in individuals with a "normal" BMI ("normal weight obesity"/metabolically unhealthy normal weight)
Waist circumference alone (without the hip ratio) is sometimes used as a simpler alternative measure with similar risk-stratification value

An elevated waist-to-hip ratio should prompt metabolic risk assessment (glucose, lipids, blood pressure) even when BMI is in the normal range, given this measure's independent contribution to cardiometabolic risk stratification beyond BMI alone
Used alongside BMI (not as a replacement) for comprehensive body composition-related risk assessment

Normal-weight obesity/metabolically unhealthy normal weight (elevated WHR with normal BMI), visceral vs subcutaneous fat metabolic risk difference, sex-specific threshold variation
A normal BMI does not exclude elevated cardiometabolic risk from central adiposity - "normal weight obesity" (normal BMI with an elevated waist-to-hip ratio) carries meaningfully elevated metabolic risk that BMI alone would miss, making waist-to-hip ratio a valuable complementary measure rather than a redundant one

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