Hassanain Toma, MD

Jingfen Zhang, Guorong Liu, Hisatomi Arima, Yuechun Li, Guojuan Cheng, Ivy Shiue, et al. Incidence and Risks of Subarachnoid Hemorrhage in China. Stroke. 2013

Zhang et al. sought to determine the incidence and risks of subarachnoid hemorrhage (SAH) in China. They performed a prospective, case-control study of Baotou population in Inner Mongolia, China. They determined the incidence of SAH to be 6.2 per 100,000. Using multi-variable analysis, they also determined the relative risk (RR) of SAH in smokers to be 2.31, while the population attributed risk (PAR) for smoking, hypertension and low income were 18%, 36% and 59%, respectively.

The authors cite a study that estimates the worldwide incidence of SAH to be 9 per 100,000. This is interesting because one could interpret their results to reveal that being of Chinese descent imparts a 50% reduction in the incidence of SAH. Sadly however, the authors also admit that the population studied is not a true representation of the general Chinese population, for example, they observed a wide disparity in tobacco use between their population and the national average.

Furthermore, the authors found that being overweight imparted protection against SAH (RR 0.55). This finding certainly puts into question our understanding of SAH pathogenesis versus the generalizability of their patient population. I, for one, have no plans to endorse weight gain to lower the risk of SAH in my patients of Chinese descent.