Do Thick Thighs Save Lives or Add QALYs?
Yes, larger thigh circumference is associated with reduced mortality and lower risk of cardiovascular disease and type 2 diabetes, though the benefit appears to have a threshold effect around 60 cm, below which risk increases substantially. 1
Mortality and Cardiovascular Benefits
The most compelling evidence comes from a prospective Danish cohort study that followed 2,816 adults for over 12 years. This study demonstrated that:
- Small thigh circumference (below approximately 60 cm) was associated with significantly increased risk of premature death and cardiovascular disease in both men and women 1
- The relationship showed a clear threshold effect: below 60 cm, risk increased dramatically, but above this threshold, having even larger thighs provided no additional mortality benefit 1
- These protective effects remained independent of abdominal obesity, general obesity (BMI), lifestyle factors, blood pressure, and lipid levels 1
- After adjusting for covariates, larger thigh circumference was negatively associated with mortality in men (though this association was not significant in women in some analyses) 2
Metabolic Disease Protection
Beyond mortality, thigh circumference demonstrates important metabolic benefits:
- Larger thigh circumference is associated with lower risk of type 2 diabetes in both men and women, independent of BMI, age, and waist circumference 2
- Greater subcutaneous thigh fat is independently associated with more favorable glucose levels in men and improved lipid profiles (lower triglycerides, higher HDL-cholesterol) in both sexes, even after accounting for harmful abdominal fat 3
- The waist-to-thigh ratio shows the greatest discriminating power for predicting type 2 diabetes compared to other anthropometric measures including BMI, waist circumference, and waist-to-hip ratio 2
The Mechanism: Muscle Mass Matters
The protective effect of larger thighs appears related to muscle mass rather than just fat:
- Thigh circumference serves as a reliable indicator of total muscle mass, strongly correlating with lean tissue volume measured by MRI 2
- The adverse effects of small thighs are likely related to insufficient muscle mass in the lower extremities 1
- Maintaining adequate muscle mass is critical for preventing sarcopenia and functional decline, which are associated with falls, fractures, frailty, and mortality 4
Clinical Application and Measurement
Thigh circumference should be measured at specific anatomical landmarks: 1 cm below the gluteal line on the right leg, below the gluteal fold on the left leg, or at mid-thigh 5, 2
The measurement offers several practical advantages:
- Simple, rapid, and low-cost assessment tool 2
- Not affected by fluid retention, unlike some other anthropometric measures 2
- Can help identify individuals at increased risk of premature morbidity and mortality in primary care settings 1
Important Caveats
The critical threshold appears to be around 60 cm—below this, risk increases substantially, but above this, additional thigh size does not confer further mortality benefit 1. This is not a case where "bigger is always better."
Gender differences exist in interpretation: the protective associations may be stronger or more consistent in men than women for certain outcomes 2. Additionally, thigh circumference reflects both muscle and fat tissue, with the fat component being the main contributor in women while men show equal dependence on both 3.
The Broader Context
While thigh circumference is protective, it should be considered alongside other evidence-based predictors of longevity: regular physical activity, healthy dietary patterns, positive psychological well-being, maintaining normal body weight, and avoiding tobacco remain the five most important modifiable factors for a long and healthy life 6.