Risk factors associated with varicocele: a narrative review.

Background and Objective: Varicocele is characterized by the dilation and tortuosity of the internal spermatic venous plexus, leading to impaired venous return, elevated testicular temperature, and ultimately compromised sperm quality. However, most previous reviews have primarily focused on the impact of varicocele on fertility, with limited comprehensive analysis of the associated risk factors contributing to its development. Therefore, this study systematically reviews the existing literature and provides an in-depth analysis of the risk factors associated with varicocele. Methods: We conducted a literature search using PubMed, selecting peer-reviewed journal articles without time restrictions. The included publications were systematically summarized and analyzed. Key Content and Findings: Varicocele predominantly occurs on the left side (90%) due to anatomical factors such as the longer left spermatic vein and its perpendicular insertion into the left renal vein, increasing hydrostatic pressure. Genetic predispositions, including polymorphisms in glutathione S-transferase (GST) and NOS3 genes, contribute to oxidative stress and venous dysfunction. Lifestyle factors such as rapid pubertal development, intense physical activity, and high-altitude residence correlate with higher incidence, while higher body mass index (BMI) may be protective. Hematological markers, including elevated platelet indices and inflammatory cytokines such as interleukin-6 (IL-6) and C-reactive protein (CRP) are linked to varicocele severity and infertility risk. Additionally, conditions like chronic obstructive pulmonary disease (COPD), chronic constipation, and autoimmune diseases like Behçet's disease exacerbate varicocele through increased intra-abdominal pressure or vascular inflammation. Conclusions: Varicocele is a condition with multiple contributing factors. Identifying high-risk individuals early, along with lifestyle changes and targeted treatments, may help reduce fertility problems linked to varicocele. Future research should focus on better understanding how this condition develops and improving treatment options to enhance outcomes or prevent it altogether.