Effects of ethnicity and gender on reliable measurements using the Sahara ultrasonometer

The objectives of this study were to evaluate the relationship between age and ultrasound (US) parameters and to assess the influences of ethnicity, sex, body mass index (BMI), and age on the ability to obtain a reliable measurement as indicated by the Sahara software. Quantitative ultrasound parameters were assessed in 1554 African American and Caucasian men and women between the ages of 18 and 93 using the Sahara ultrasonometer. The relationships among age and broadband ultrasound attenuation, speed of sound (SOS), qualitative ultrasound index, and bone mineral density showed a decline in all US parameters with age. The relationship was linear for males and curvilinear for females for all parameters except SOS, which was also linear for females. The Sahara software indicated that 66% of the measurements for African American men were unreliable, 27% for African American females, 14% for Caucasian males, and 6% for Caucasian females. The factors found to contribute to the likelihood (odds ratio, [95% confidence interval]) of obtaining an unreliable estimate were having a high BMI (1.13, [1.1, 1.16]), being of African American ethnicity (5.29 [3.78, 7.41]), and being male (3.1 [2.8, 4.1]). Our study provides evidence that US results from the Sahara should be interpreted with caution in males, in individuals with African American ancestry, and in individuals with a high BMI.