Body fat distribution is an important risk indicator for cardiovascular and metabolic diseases. Ultrasonography (US) is a non-invasive tool without adverse effects, validated to measure subcutaneous adipose tissue (SAT) however its use is evaluator dependent. To our knowledge, there are no reliable studies that measure the thickness of the SAT in the supra umbilical scar regions using the US.

To evaluate the intra-rater reliability for measuring supra-abdominal SAT thickness in the US in adults.

We evaluated 44 participants (22 women and 22 men), aged between 20 and 42 years. For each gender, 12 eutrophic and 10 overweight participants were included. The participants were submitted to two days of SAT thickness evaluation, with a difference of 7 days between evaluations, using ultrasound (Ultrasound GE Healthcare Venue 40®). The measurements were performed by a linear transducer with a frequency of 12 MHz, positioned transversally one centimeter above and one centimeter below the umbilical scar. The evaluations were always performed by the same evaluator. Three measurements were taken in each region, and the three measurements' average was used. Intra-rater reliability was evaluated using the intraclass correlation coefficient (ICC). The ICC classification was considered low (<0.50), moderate (0.50-0.75), good (0.75-0.90), and excellent (>0.90) correlation. The level of statistical significance was set at p<0.05.

Participants were characterized according to age (females: 25(23-32 years); males: 25(23-29)), body mass (females: 63.85±9.96; males: 78.93±11.03), height (females: 1.62±0.06 and males: 1.77±0.05), and body mass index (females: 24.20±3.47 and males: 25.22±3.30). The supra-abdominal ICC in women was 0.82 (confidence interval = 0.62-0.92), and in men, it was 0.91 (0.81-0.96). The infra-abdominal ICC for women was 0.77 (0.52-0.90) and for men was 0.89 (0.75-0.95). The reliability of the supra-abdominal SAT thickness measurement in women was considered good and in men it was excellent. On the other hand, in the infra-abdominal region, it was considered good for both women and men.

Ultrasonographic assessment for supra and infra-abdominal SAT can be performed in adults. Furthermore, there are differences between the reliability of measurements in the supra-abdominal region in men and women.

The US is characterized as a safe, cost-effective, and accurate method. Besides being painless, non-invasive, and not exposing individuals to ionizing radiation. Considering that the US is a method highly dependent on the skill of the operator, this study evaluated the intra-rater reliability for assessing the thickness of the abdominal SAT of the supra and infra-abdominal regions in men and women. This amplified assessment can be used to track changes in at-risk populations and throughout aging.