Abstract：
OBJECTIVE: Intracranial aneurysms are more common in women than in men. Some anatomical variants of the circle of Willis (CoW) are associated with a higher risk of developing intracranial aneurysms. We hypothesized that variations of the CoW are sex dependent which may partly explain why intracranial aneurysms are more common in women. We systematically reviewed and meta-analyzed the literature to compare the presence of anatomical variations of the CoW between women and men in the general population.
METHODS: A systematic search in Pubmed and EMBASE using predefined criteria, following the PRISMA guidelines was performed. The presence of different CoW anatomical variants and a complete CoW was compared between women and men using an inverse variance weighted random effects meta-analysis to calculate relative risks (RR) with 95% confidence intervals (95% CIs).
RESULTS: Fourteen studies were included reporting on 5478 healthy participants (2511 women, 2967 men). Bilateral fetal type posterior cerebral arteries (RR 2.79; 95%CI 1.65-4.72, I2=0%), and a complete CoW (RR 1.24, 95%CI 1.13-1.36; I2=0%) were more prevalent in women than in men. The variants absence or hypoplasia of one of the anterior cerebral arteries (RR 0.58, 95%CI 0.38-0.88, I2=57%) and hypoplasia or absence of both posterior communicating arteries (RR 0.79, 95%CI 0.71-0.87, I2=0%) were more prevalent in men.
CONCLUSIONS: Several anatomical variations of the CoW are sex dependent, with some variants being more common in women while others in men. Future research should assess how these sex-specific CoW variants relate to the sex-specific occurrence of intracranial aneurysms.
METHODS: A systematic search in Pubmed and EMBASE using predefined criteria, following the PRISMA guidelines was performed. The presence of different CoW anatomical variants and a complete CoW was compared between women and men using an inverse variance weighted random effects meta-analysis to calculate relative risks (RR) with 95% confidence intervals (95% CIs).
RESULTS: Fourteen studies were included reporting on 5478 healthy participants (2511 women, 2967 men). Bilateral fetal type posterior cerebral arteries (RR 2.79; 95%CI 1.65-4.72, I2=0%), and a complete CoW (RR 1.24, 95%CI 1.13-1.36; I2=0%) were more prevalent in women than in men. The variants absence or hypoplasia of one of the anterior cerebral arteries (RR 0.58, 95%CI 0.38-0.88, I2=57%) and hypoplasia or absence of both posterior communicating arteries (RR 0.79, 95%CI 0.71-0.87, I2=0%) were more prevalent in men.
CONCLUSIONS: Several anatomical variations of the CoW are sex dependent, with some variants being more common in women while others in men. Future research should assess how these sex-specific CoW variants relate to the sex-specific occurrence of intracranial aneurysms.
摘要：
目的：颅内动脉瘤在女性中比在男性中更常见。威利斯环（CoW）的一些解剖变体与颅内动脉瘤的高风险相关。我们假设CoW的变异与性别有关，这可能部分解释了为什么颅内动脉瘤在女性中更常见。我们系统地回顾和荟萃分析了文献，以比较普通人群中男女之间CoW解剖变异的存在。
方法：使用预定义标准在Pubmed和EMBASE中进行系统搜索，遵循PRISMA指南。使用逆方差加权随机效应荟萃分析在女性和男性之间比较不同CoW解剖变异和完整CoW的存在，以95%置信区间(95%CIs)计算相对风险(RR)。
结果：纳入了14项研究，报告了5478名健康参与者（2511名女性，2967名男子）。双侧胎儿型大脑后动脉（RR2.79;95CI1.65-4.72，I2=0%），完全CoW(RR1.24,95CI1.13-1.36;I2=0%)在女性中比男性更普遍。大脑前动脉之一的变异缺失或发育不全（RR0.58，95CI0.38-0.88，I2=57％）和两个后交通动脉的发育不全或缺失（RR0.79，95CI0.71-0.87，I2=0％）在男性中更为普遍。
结论：CoW的一些解剖学变异是性别依赖性的，有些变体在女性中更常见，而另一些则在男性中更常见。未来的研究应该评估这些性别特异性CoW变异如何与颅内动脉瘤的性别特异性发生相关。
方法：使用预定义标准在Pubmed和EMBASE中进行系统搜索，遵循PRISMA指南。使用逆方差加权随机效应荟萃分析在女性和男性之间比较不同CoW解剖变异和完整CoW的存在，以95%置信区间(95%CIs)计算相对风险(RR)。
结果：纳入了14项研究，报告了5478名健康参与者（2511名女性，2967名男子）。双侧胎儿型大脑后动脉（RR2.79;95CI1.65-4.72，I2=0%），完全CoW(RR1.24,95CI1.13-1.36;I2=0%)在女性中比男性更普遍。大脑前动脉之一的变异缺失或发育不全（RR0.58，95CI0.38-0.88，I2=57％）和两个后交通动脉的发育不全或缺失（RR0.79，95CI0.71-0.87，I2=0％）在男性中更为普遍。
结论：CoW的一些解剖学变异是性别依赖性的，有些变体在女性中更常见，而另一些则在男性中更常见。未来的研究应该评估这些性别特异性CoW变异如何与颅内动脉瘤的性别特异性发生相关。
