Two studies found that there were no statistically significant differences in LH levels between patients who had had COVID-19 and controls [31, 37], three studies found that LH was significantly increased in patients who had had COVID-19 compared to controls [26, 33, 38], one study found that LH was significantly decreased in patients who had had COVID-19 versus controls [39]. Here, PLOD1 is linked to COVID-19.