A cross-sectional study of the association of age, race and ethnicity, and body mass index with sex steroid hormone marker profiles among men in the National Health and Nutrition Examination Survey (NHANES III)

Association between visceral adipose tissue and total testosterone among the United States male adults: a cross-sectional study

Visceral adipose tissue (VAT) is regarded as an important risk factor for obesity-related diseases. The results of the association between VAT and total testosterone (TT) are controversial and whether this association is nonlinear is still unknown. 3971 male participants who were aged 20-59 years from the National Health and Nutrition Examination Surveys 2011-2016 were included. VAT area was measured by dual-energy x-ray absorptiometry. TT in serum was assessed utilizing the isotope dilution liquid chromatography-tandem mass spectrometry technique. Linear regression models assessed the associations between VAT area and TT. A restricted cubic spline model was employed to investigate nonlinear relationships. A two-piecewise linear regression model was applied to determine the threshold effect. Subgroup analyses were conducted. The weighted methods were utilized in all analyses. VAT area was inversely associated with TT in the crude and adjusted models. In the fully adjusted model, VAT area was associated with TT (β = -0.59, 95% confidence interval [CI] = -0.74, -0.43) and compared to the first tertile of VAT area, the second and the third tertile had a lower TT level, the β and 95% CI = -65.49 (-83.72, -47.25) and -97.57 (-121.86, -73.27) respectively. We found these inverse associations were nonlinear. The cutoff point of the VAT area was 126 cm2. When the VAT area was <126 cm2, VAT area was significantly associated with a lower TT level (β = -1.55, 95% CI = -1.93 to -1.17, p < 0.0001). However, when the VAT area was ≥126 cm2, this association was less apparent (β = -0.26, 95% CI = -0.52 to 0.01, p = 0.06). No significant interactions among different ages (<50 or ≥50 years), marital, and physical activity status were found. These findings underscore the potential for VAT area as a modifiable indicator for improving testosterone deficiency.

1,1-Difluoroethane Detection Time in Blood after Inhalation Abuse Estimated by Monte Carlo PBPK Modeling

(1) Background: Inhalant abuse and misuse are still widespread problems. 1,1-Difluoroethane abuse is reported to be potentially fatal and to cause acute and chronic adverse health effects. Lab testing for difluoroethane is seldom done, partly because the maximum detection time (MDT) is unknown. We sought to reliably estimate the MDT of difluoroethane in blood after inhalation abuse; (2) Methods: MDT were estimated for the adult male American population using a physiologically based pharmacokinetic (PBPK) model and abuse patterns detailed by two individuals. Based on sensitivity analyses, variability in huffing pattern and body mass index was introduced in the model by Monte Carlo simulation; (3) Results: With a detection limit of 0.14 mg/L, the median MDT was estimated to be 10.5 h (5th-95th percentile 7.8-12.8 h) after the 2-h abuse scenario and 13.5 h (10.5-15.8 h) after the 6-h scenario. The ranges reflect variability in body mass index and hence amount of body fat; (4) Conclusions: Our simulations suggest that the MDT of difluoroethane in blood after abuse ranges from 7.8 to 15.8 h. Although shorter compared to many other drugs, these MDT are sufficient to allow for testing several hours after suspected intoxication in a patient.