A comparative analysis of risk factors and stroke risk for Asian and non-Asian men: The Asia Pacific Cohort Studies Collaboration Karice K. Hyun 1 , Rachel R. Huxley 1,2 *, Hisatomi Arima 1 , Jean Woo 3 , Tai Hing Lam 4 , Hirotsugu Ueshima 5 , Xianghua Fang 6 , Sanne A. E. Peters 1,7 , Sun Ha Jee 8 , Graham G. Giles 9,10,11 , Federica Barzi 1 , and Mark Woodward 1,12 Background The risk of stroke is high in men among both Asian and non-Asian populations, despite differences in risk factor profiles; whether risk factors act similarly in these popu- lations is unknown. Aim To study the associations between five major risk factors and stroke risk, comparing Asian with non-Asian men. Methods We obtained data from the Asia Pacific Cohort Studies Collaboration, a pooled analysis of individual partici- pant data from 44 studies involving 386 411 men with 9·4 years follow-up. Using cohorts from Asia and Australia/New Zealand Cox models were fitted to estimate risk factor asso- ciations for ischemic and haemorrhagic stroke. Results We identified significant, positive associations between all five risk factors and risk of ischemic stroke. The associations between body mass index, smoking, and diabetes with ischemic stroke were comparable for men from Asia and Australia/New Zealand. The association between systolic blood pressure and ischemic stroke was stronger for Asian than Australia/New Zealand cohorts, whereas the reverse was true for total cholesterol. For haemorrhagic stroke, only sys- tolic blood pressure and smoking were associated with increased risk, although the relationship with systolic blood pressure was significantly stronger for men from Asia than Australia/New Zealand (P interaction = 0·03), whereas the reverse was true for smoking (P interaction = 0·001). There was an inverse trend of total cholesterol with haemorrhagic stroke, significant only for Asian men. Conclusions Men from the Asia-Pacific region share common risk factors for stroke. Strategies aimed at lowering population levels of systolic blood pressure, total cholesterol, body mass index, smoking, and diabetes are likely to be beneficial in reducing stroke risk, particularly for ischemic stroke, across the region. Key words: Asia, epidemiology, haemorrhagic stroke, ischemic stroke, meta-analysis, non-Asia, risk factors Introduction Most population studies show the age-adjusted incidence of stroke to be higher for men than women (1–3), but the reasons for this have yet to be fully elucidated. The sex disparity in stroke incidence and mortality is likely to be due to a combination of factors that includes the tendency for men, compared with women, to have more adverse cardiovascular risk profiles (espe- cially in higher-income countries) and a lower level of awareness of the risk factors and symptoms of stroke (4). There are also substantial between-country differences in the incidence of ische- mic stroke (IS) and haemorrhagic stroke (HS), due to their dif- ferent pathophysiology (5). HS is the less common stroke subtype overall, but is more common in Asians than non-Asians. Differ- ences in stroke incidence have been ascribed, in part, to inter- country differences in the mean population level of risk factors and to changes over time in risk factor levels due to pharmaco- logical and nonpharmacological interventions (6,7). Country- specific time-trend data illustrate this point. In Australia, for example, in the decade 1998–2009, the proportion of deaths from stroke remained largely unchanged at around 6–7% of all fatali- ties (8) (Fig. S1). In South Korea, the opposing negative and posi- tive trends in HS and IS mortality rates, respectively, have meant that the proportion of all deaths due to stroke has remained high over the same time period (around 20%; Fig. S2) (9). In contrast, in Japan the proportion of all deaths due to stroke has declined by nearly one-third during 1995–2010, largely due to falls in mortal- ity from IS (Fig. S3) (10). Given the substantial differences in population baseline risk and incidence of stroke subtypes between Asian and non-Asian men, comparisons of the risk factor–stroke relationships for each population may be informative. Using individual-participant data from the Asia Pacific Cohort Studies Collaboration (APCSC), we examined regional differences in the associations between major cardiovascular risk factors and stroke. Methods We have published details of the APCSC previously (11,12). In brief, eligible studies had to have a cohort design with selection Correspondence: Rachel Huxley*, Division of Epidemiology & Community Health, University of Minnesota, 1300 S 2nd Street, Suite 300, Minneapolis, MN 55454, USA. E-mail: rhuxley@umn.edu 1 The George Institute for Global Health, University of Sydney, Sydney, NSW, Australia 2 Division of Epidemiology and Community Health, School of Public Health University of Minnesota, Minneapolis, MN, USA 3 Chinese University of Hong Kong, Hong Kong, China 4 Department of Community Medicine, The University of Hong Kong, Hong Kong, China 5 Department of Health Science, Shiga University of Medical Science, Shiga, Japan 6 Xuanwu Hospital, Capital Medical University, Beijing, China 7 Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands 8 Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, Korea 9 Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Vic., Australia 10 Centre for MEGA Epidemiology, School of Public Health, University of Melbourne, Melbourne, Vic., Australia 11 Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Vic., Australia 12 Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA Conflict of interest: None declared. DOI: 10.1111/ijs.12166 Research © 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization 606 Vol 8, December 2013, 606–611