OBJECTIVE

A case-control study was conducted in Japan to examine the joint effects of oxidative stress and antioxidants on the risk of subarachnoid hemorrhage (SAH).

METHODS

The study included 201 consecutive patients with first spontaneous SAH aged 30 to 79 years who had aneurysm(s) confirmed by angiography and/or computed tomographic scan and were admitted to two medical hospitals in Nagoya, Japan, from April 1992 to March 1997. Community control subjects were identified and matched to each case by gender and age (+/-2 years). Conditional logistic regression modeling was used to compute odds ratios (ORs) adjusted for body mass index, physical activity, family history of SAH, a history of hypertension, drinking habit, and frequency of green-yellow vegetables and fruits, and tea consumption.

RESULTS

The greatest risk for SAH was posed by combination of current smoking and a less frequent intake of soy products (adjusted OR = 5.3; 95% confidence interval [CI], 2.0 to 14.3). Less frequent intake of soy products significantly elevated SAH risk, independent of smoking habits.

CONCLUSIONS

These data suggested that enhancement of the antioxidant defense system such as much intake of soy products may be important in preventing SAH rather than the reduction of such oxidants as smoking. Our findings should prove useful for targeting individuals/populations in programs for primary prevention of SAH.