PRL and Insulin resistance: Furthermore, although it is very arbitrary, when insulin resistance was defined as HOMA-R ≥1.6, to increase number of such subjects (n = 33) and thus increase statistical power, multiple logistic regression analyses showed that high serum PRL levels were significantly associated with insulin resistance (OR: 2.67, 95% CI: 1.01–7.06) in men with a serum PRL level below the peak (S3 Table).