As with all therapeutic recommendations, patient preferences must be considered. Risk factors, which directly increase disease prob- ability and if absent or removed reduce disease probability, or risk markers, which are attributes or exposures associated with increased probability of disease but are not necessarily of a first stroke, were classified according to their potential for modification.7 Although this distinction is some- what subjective, risk factors considered both well documented and modifiable were those with clear, supportive epidemiolog- ical evidence and evidence of risk reduction when modified in the context of randomized clinical trials. Less well-docu- mented or potentially modifiable risk factors were those either with less clear epidemiological evidence or without evidence from randomized clinical trials demonstrating a reduction of stroke risk when modified. Assessing the Risk of First Stroke It may be helpful for healthcare providers and patients to be able to estimate risk for a first stroke for an individual patient. Patients prefer being told their own individual risk through the use of a global risk assessment tool, although it has only a small effect on preferences for reducing risk and no effect on patient beliefs or behavior compared with standard risk As detailed in other sections, numerous individual factors can contribute to stroke risk. The levels of evidence supporting a causal relationship among several of these factors and stroke vary, and specific or proven treat- ments for some may be lacking. Although most risk factors have an independent effect, there may be important interac- tions between individual factors that need to be considered in predicting overall risk or choosing an appropriate risk modifi- cation program. 