Finally, Campos-Rodriguez and colleagues17 sought to answer if OSA is a potential risk factor in cardiovascular death in women. In a prospective, controlled cohort examination of 1,116 women referred for OSA in Spain (AHI, 10 to ≥ 30), the authors calculated cardiovascular mortality rates for treated and untreated OSA by dividing the number of cardiovascular deaths by the number of person-years accumulated during follow-up, with rates expressed as per 100 person-years. Untreated groups of mild to moderate and severe OSA had higher mortality rates (0.94 per 100 person-years [95% CI, 0.10-2.40], P = .034; 3.71 per 100 person-years [95% CI, 0.09-7.50], P < .001, respectively) as compared with control subjects (0.28 per 100 person-years [95% CI, 0.10-0.91]), and CPAP treatment showed reduced rates (mild to moderate: 0.10 [95% CI, 0.08-0.59], severe: 0.31 [95% CI, 0.11-0.84]), although P values were not listed. Compared with the control group, the fully adjusted hazard ratios for cardiovascular mortality were 0.19 (95% CI, 0.02-1.67; P = .135) for the CPAP-treated, mild to moderate OSA group, 1.60 (95% CI, 0.52-4.90; P = .40) for the untreated, mild to moderate OSA group, 0.55 (95% CI, 0.17-1.74; P = .31) for the CPAP-treated, severe OSA group, and 3.50 (95% CI, 1.23-9.98; P = .019) for the untreated, severe OSA group. Cautions to note include that control subjects used for this study were patients referred to the sleep units and found to have AHI < 10 and that the untreated group may also be noncompliant with other medical recommendations, all creating possible bias. Moreover, the statistical power was not enough to obtain other cardiovascular cofounders, such as age, hormonal status, and previous cardiac events, which may have contributed to the small number of deaths seen; cardiac confounders may have limited the significance of cardiovascular death seen in mild to moderate OSA as compared with severe OSA, an effect also shown in the male population. Further studies in randomized, controlled populations of women are needed to elucidate whether severe OSA is an independent risk factor for cardiovascular mortality and if mild to moderate disease plays any cardiovascular role.