Reducing the global burden of stroke: interstroke

We have received research funding from Takeda Pharmaceuticals; TAB has been Torgerson JS, Hauptman J, Boldrin MN, Sjostrom L. Xenical in the prevention on a speakers’ panel for and has received travel and accommodation expenses of diabetes in obese subjects (XENDOS) study. Diabetes Care 2004; 27: 155–61.
Buchanan TA. (How) Can we prevent type 2 diabetes? Diabetes 2007; Tuomilehto J, Lindstrom J, Eriksson JG, et al, for the Finnish Diabetes 56: 1502–07.
Prevention Study Group. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med The Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes 2001; 344: 1343–50.
Research (NAVIGATOR) Study Group. Eff ect of nateglinide on the incidence of diabetes and cardiovascular events. N Engl J Med 2010; Diabetes Prevention Program Research Group. Reduction in the incidence 362: 1477–90.
of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med
2002; 346: 393–403.
Zinman B, Harris SB, Neuman J, et al. Low-dose combination therapy with rosiglitazone and metformin to prevent type 2 diabetes mellitus Chaisson JL, Josse RG, Gomis R, Hanefeld M, Karasik A, Laakso M, for the (CANOE trial): a double-blind randomised controlled study. Lancet 2010; STOP-NIDDM Research Group. Acarbose for prevention of type 2 diabetes published online June 3. DOI:10.1016/S0140-6736(10)60490-4.
mellitus: the STOP-NIDDM randomised trial. Lancet 2002; 359: 2072–77.
10 Hazzard WR, Crockford PM, Buchanan KD, Vance JE, Chen R, Williams RH. Buchanan TA, Xiang AH, Peters RK, et al. Preservation of pancreatic β-cell A double antibody immunoassay for glucagon. Diabetes 1968; function and prevention of type 2 diabetes by pharmacological treatment of 17: 179–86.
insulin resistance in high-risk Hispanic women. Diabetes 2002; 51: 2796–803.
11 Xiang A, Peters RK, Kjo SL, et al. Eff ect of pioglitazone on pancreatic DREAM Trial Investigators. Eff ect of rosiglitazone on the frequency of β-cell function and diabetes risk in Hispanic women with prior gestational diabetes in patients with impaired glucose tolerance or impaired fasting diabetes. Diabetes 2006; 55: 517–22.
glucose: randomised controlled trial. Lancet 2006; 368: 1096–105.
Reducing the global burden of stroke: INTERSTROKE
Published Online
Stroke is the second leading cause of death globally, countries. In The Lancet today, the INTERSTROKE with more than 85% of deaths from stroke occurring in investigators3 report the initial fi ndings from their developing countries.1,2 However, there has been little phase 1 case-control study of risk factors for stroke See Articles page 112
research to identify the causes of stroke in low-income in 22 countries worldwide. The fi ndings suggest that and middle-income countries. An understanding of ten key risk factors explain 90% of the population-the risk factors for stroke in these countries is crucial attributable risk for stroke, and that the risk factors to determine priorities and strategies for reversing the for stroke are similar to those previously identifi ed rapidly rising rates of stroke mortality in developing for myocardial infarction in the related INTERHEART The INTERSTROKE investigators classifi ed participants INTERSTROKE
INTERHEART
(all stroke; 3000 cases,
(acute myocardial infarction;
into fi ve regions: high-income countries, South America, 3000 controls)3*
15 152 cases, 14 820 controls)4†
southeast Asia (including China), India, and Africa. They found that a self-reported history of hypertension or acute blood pressure of higher than 160/90 mm Hg was the most important risk factor for both ischaemic and intracerebral haemorrhagic stroke. Whilst hypertension is well established as the most important cause of stroke in high-income countries, INTERSTROKE confi rms that it is also the most important risk factor for stroke in developing countries.5 This fi nding is particularly relevant because it highlights the need for health authorities in these regions to develop strategies to screen the general population for high blood pressure and, if necessary, off er aff ordable treatment to reduce the burden of stroke. It also provides an impetus to develop population-wide strategies to reduce the salt Data are population-attributable risk (99% CI). *Adjusted for all stroke risk factors apart from ratio of apolipoproteins B to A1. †Adjusted for all myocardial infarction risk factors. ‡See original article for defi nition of risk factor and content in the diet of individuals in these countries.6 methods used to calculate population-attributable risk.
Smoking and abdominal obesity, as measured by Table: Comparison of the population-attributable risk (99% CI) for common risk factors‡ in the
waist-to-hip ratio, were also identifi ed as important risk INTERSTROKE and INTERHEART studies
factors for stroke. Current smokers had a signifi cantly www.thelancet.com Vol 376 July 10, 2010
higher risk of stroke in all regions, which reinforces the Phase 1 of INTERSTROKE suggests that hypertension, need to reduce the high smoking rates in countries such smoking, abdominal obesity, physical inactivity, and as China and India through tough anti-smoking policies diet are the most important modifi able risk factors for if a growing stroke and coronary disease epidemic is to stroke. These important fi ndings should help to inform be averted.7,8 The identifi cation of waist-to-hip ratio (as stroke prevention strategies around the world and to opposed to body-mass index) as a risk factor for stroke reduce the global burden of stroke.
is consistent with previous INTERHEART fi ndings for myocardial infarction, and provides further evidence Jack V Tuthat this ratio might be a better measure of obesity to Institute for Clinical Evaluative Sciences, Sunnybrook Schulich Heart identify individuals at high risk for these disorders.9 A Centre, University of Toronto, Toronto, ON, Canada M4N 3M5 surprising fi nding was the relatively low prevalence of I am supported by a Canada Research Chair in Health Services Research and a cardiac causes of stroke (eg, atrial fi brillation, rheumatic Career Investigator Award from the Heart and Stroke Foundation of Ontario. heart disease) in China and India compared with high- I declare that I have no confl icts of interest.
income countries, but this result may refl ect, in part, 1 Johnston SC, Mendis S, Mathers CD. Global variation in stroke burden and mortality: estimates from monitoring, surveillance, and modelling. lower rates of cardiac diagnostic testing.
Lancet Neurol 2009; 8: 345–54.
Identifying the causes of stroke across many diverse 2 Strong K, Mathers C, Bonita R. Preventing stroke: saving lives around the world. Lancet Neurol 2007; 6: 182–87.
regions with a standardised approach is a diffi O’Donnell MJ, Xavier D, Liu L, et al, on behalf of the INTERSTROKE investigators. Risk factors for ischaemic and intracerebral haemorrhagic research undertaking for many reasons. Although a large stroke in 22 countries (the INTERSTROKE study): a case-control study. Lancet international prospective cohort study might be the 2010; published online June 18. DOI:10.1016/S0140-6736(10)60834-3.
Yusuf S, Hawken S, Ôunpuu S, et al, on behalf of the INTERHEART Study ideal, one would need to enrol a very large sample in view Investigators. Eff ect of potentially modifi able risk factors associated with of the relatively low incidence of stroke in the general myocardial infarction in 52 countries (the INTERHEART study): case-control
study. Lancet 2004; 364: 937–52.
population, and the challenges of the long follow- Lawes CM, Bennett DA, Feigin VL, Rodgers A. Blood pressure and stroke: up required would be considerable. A more effi an overview of published reviews. Stroke 2004; 35: 776–85.
Asaria P, Chisholm D, Mathers C, Ezzati M, Beaglehole R. Chronic disease approach is to use a matched case-control design, as in prevention: health eff ects and fi nancial costs of strategies to reduce salt
intake and control tobacco use. Lancet 2007; 370: 2044–53.
INTERSTROKE, in which patients (or their proxies if they 7 Gu D, Kelly TN, Wu X, et al. Mortality attributable to smoking in China. could not communicate) in hospital with acute stroke N Engl J Med 2009; 360: 150–59.
Jha P, Jacob B, Gajalakshmi V, et al, for the RGI-CGHR Investigators. were interviewed and examined for possible risk factors, A nationally representative case-control study of smoking and death in and results compared with a control population matched India. N Engl J Med 2008; 358: 1137–47.
Yusuf S, Hawken S, Ôunpuu S, et al, on behalf of the INTERHEART Study for age and sex from the hospital or the community.10 Investigators. Obesity and the risk of myocardial infarction in 27 000 Such a design can yield useful information but selection participants from 52 countries: a case-control study. Lancet 2005;
366: 1640–49.
or recall biases might occur in terms of the individuals (or 10 O’Donnell M, Xavier D, Diener C, et al. Rationale and design of INTERSTROKE: a global case-control study of risk factors for stroke. their proxies) who agree to take part as either cases or Neuroepidemiology 2010; 35: 36–44.
controls.11,12 The INTERSTROKE investigators were aware 11 Tu JV, Willison DJ, Silver FL, et al, for the Investigators in the Registry of the Canadian Stroke Network. Impracticability of informed consent in the of these limitations and did sensitivity analyses that Registry of the Canadian Stroke Network. N Engl J Med 2004; showed that their fi ndings were generally consistent 350: 1414–21.
12 Schulz UG, Rothwell PM. Diff erences in vascular risk factors between between respondents (patient or proxies) and between etiological subtypes of ischemic stroke: importance of population-based studies. Stroke 2003; 34: 2050–59.
Public health research funding: independence is important
The Diet and Health Research Industry Club (DRINC) is while enhancing the international competitiveness See Editorial page 69
a £10 million (US$16·7 million, €11·2 million), 5-year of the UK’s food industry and its ability to develop
partnership between the UK’s Biotechnology and healthier foods. Research includes design of foods with
Biological Sciences Research Council (BBSRC) and a enhanced nutritional properties and assessment of the
consortium of leading companies.1 DRINC’s goal is to health benefi ts of bioactive ingredients. The companies
generate high-quality research into diet and health involved, which include Cadbury, Coca Cola, Nestlé,
www.thelancet.com Vol 376 July 10, 2010

Source: http://surveillance.mcgill.ca/trac/star/raw-attachment/wiki/StarWebinarsCad/Tu_Lancet_2010_7574.pdf