It should be considered, however, that the trend for higher serum LH found in our meta-analysis refers mainly to studies performed in the 1990s (Figure 3 Panel D), including HIV patients who had survived the disease in the pre-HAART era; these patients were exposed to several opportunistic infections that, at the time, often also involved the testis, thus accounting for primary hypogonadism [53,54]. This evidence concerns the gene PLOD1 and Opportunistic infection.