Calf circumference: cutoff values from the NHANES 1999-2006

Area of Science:

• Geriatric Medicine
• Anthropometry
• Sarcopenia Research

Background:

• Calf circumference (CC) is a practical marker for skeletal muscle (SM) mass and sarcopenia in older adults.
• Existing CC cutoff values lack representation across the full adult lifespan.
• A need exists for updated CC reference values in diverse populations.

Purpose of the Study:

• To establish calf circumference (CC) cutoff points for skeletal muscle (SM) assessment in a diverse adult population.
• To identify confounding factors, such as BMI, affecting CC measurements.
• To provide updated reference values for diagnosing low SM and sarcopenia.

Main Methods:

• Utilized data from the NHANES 1999-2006 sample (n=17,789) including demographic, anthropometric, and DXA imaging data.
• Partitioned the adult sample (≥18 years) by sex, ethnicity, and race.
• Derived CC cutoff points based on a reference population (18-39 years, BMI 18.5-24.9) at 1 and 2 SDs below the mean, adjusting for BMI.

Main Results:

• CC strongly correlated with appendicular lean mass (r=0.84-0.86, P<0.001).
• Significant CC differences were observed across sex, ethnicity, race, and BMI groups.
• Developed rounded CC cutoff values: males (34/32 cm), females (33/31 cm) for moderate/severe low SM, recommending BMI-adjusted values for non-normal weight ranges.

Conclusions:

• Defined calf circumference (CC) values in a diverse adult population.
• Introduced a BMI-adjustment approach to mitigate adiposity confounding effects.
• Enhanced CC's utility as a clinical estimate of skeletal muscle (SM) mass.