CRP and obstructive sleep apnea syndrome: Moreover, increased levels of proinflammatory cytokines may be associated with spermatogenesis, sperm quality, and fertility.29,30 The escalation of inflammatory cytokines, including interleukin 6, tumor necrosis factor, and C-reactive protein, was reported in patients with OSA.31 Findings of the previous research and the present study provide evidence that OSA is a substantial risk factor in infertility.