TF and obesity due to melanocortin 4 receptor deficiency: Among women without obesity (BMI < 30), in unadjusted continuous outcome analyses, women taking prescription opioids (n = 195) had higher waist circumference, fasting triglycerides, and mean corpuscular volume, and lower HDL, serum iron, percent transferrin saturation, and serum folate levels compared to women not taking prescription opioids (n = 4535, Supplemental Table S5).