Stroke incidence

In many parts of Britain in the 1930s, excellent records of the hirthweight of hahies were made. When the causes of death in the subsequent adults were studied and medical records investigated, a strong correlation between low hirthweight, stroke incidence of mortahty from cardiovascular disease and diabetes was observed (Barker, 1998). It may be that low hirthweight is due to undemutrition of the mother. 

Outcome (1) CHD mortality (2) MI incidence Stroke incidence CHD mortality CHD mortality CHD mortality CHD mortality (1) CHD mortality (2) stroke mort... 

LeppalaJM, VirtamoJ, Fogelholm R, et al. Controlled trial of alpha-tocopherol and beta-carotene supplements on stroke incidence and mortality in male smokers. Atherioscler Thromb Vase Biol 2000 20 250-235. 

Stroke mortality rises rapidly with age (Rothwell et al. 2005). The increase in mortality in the elderly is mainly a result of the steep rise in the incidence of stroke with age, but also, to a lesser extent, reflects the increase in case fataUty in older patients. In other words, older people are more likely to have a stroke (incidence) and, if they do have one, it is more likely to be fatal (case fatality). 

Stroke prevalence is the total number of people with stroke in a population at a given time and is usually measured by cross-sectional surveys (Box 1.2). It is a function of stroke incidence and survival and, therefore, varies over time and between populations with differing age and sex structures. In the UK, stroke prevalence is approximately 5/1000 population and in 65 to 74 year olds is approximately 50/1000 in men and 25/1000 in... 

The most recent studies of time trends in stroke incidence do suggest that age-specific incidence is now falling (Sarti et al. 2003 Rothwell et at. 2004 Anderson et al. 2005 Hardie et al. 2005). Between the periods 1981-1984 and 2002-2004, a 40% reduction in the incidence of fatal and disabling stroke was found in Oxfordshire, UK (Rothwell et al. 2004), although this reduction was less marked in the oldest old (Fig. 1.3). High-quality population-based studies of time trends in TIA and minor stroke are lacking. However, moderate rises in TIA incidence were reported in Oxfordshire, UK, between the periods... 

Maori and Pacific Islands. People in New Zealand have a higher stroke incidence than Europeans, perhaps owing to differences in risk factors and health-related behaviors (Bonita et al. 1997 Feigin et al. 2006). 

Deprivation. In the UK, both stroke incidence and poor outcome after stroke are greater in areas of socioeconomic disadvantage (Kaplan and Keil 1993 Avendano et al. 2004). This is partly because poverty is associated with adverse health behaviors and risk factors such as smoking (Hart et al. 2000a). There is also evidence that poor maternal and infant health is associated with increased mortality from stroke in later life (Barker 1995 Martyn et al. 1996). However, the adverse effect of socioeconomic deprivation also appears to be cumulative throughout life (Davey Smith et al. 1997 Hart et al. 2000b). 

In most studies, both stroke mortality and hospital admission rates are higher in winter than in summer (Douglas et al. 1991 Pan et al. 1995 Feigin and Weibers 1997). This seasonal variation might be explained by the complications of stroke being more likely to occur in the winter (e.g. pneumonia) and cannot simply be assumed to reflect stroke incidence. Where incidence has been measured in the community, there is little seasonal variation, at least in temperate climates, although primary intracerebral hemorrhage is somewhat more likely in the winter months and on cold days (Rothwell et al. 1996 Jakovljevic et al. 1996). 

Anderson CS, Carter KN, Hackett ML et al. (2005). Study Group. Trends in stroke incidence in Auckland, New Zealand, during 1981 to 2003. Stroke 36 2087-2093... 

Bonita R, Stewart A, Beaglehole R (1990). International trends in stroke mortality 1970-1985. Stroke 21 989-992 Bonita R, Broad jB, Beaglehole R (1993). Changes in stroke incidence and case-fataUty in Auckland New Zealand 1981-1991. Lancet 342 1470-1473... 

Johansson B, Norrving B, Lindgren A (2000). Increased stroke incidence in Lund-Orup, Sweden between 1983 to 1985 and 1993 to 1995. Stroke 31 481-486... 

Is stroke incidence related to season or temperature Lancet 347 934-936... 

Rothwell PM, Coull AJ, Giles MF et al. (2004). Change in stroke incidence, mortality, case-fatality, severity and risk factors in Oxfordshire, UK from 1981 to 2004 (Oxford Vascular Study). Lancet 363 1925-1933 Rothwell PM, Coull AJ, Silver LE et al. (2005). Population-based study of event-rate, incidence, case fatality and mortality for all acute vascular events in all arterial territories (Oxford Vascular Study). 

Stegmayr B, Asplund K, Wester PO (1994). Trends in incidence, case fatality rate, and severity of stroke in Northern Sweden, 1985-1991. Stroke 25 1738-1745 Sudlow CLM, Warlow CP (1996). Comparing stroke incidence worldwide. What makes studies comparable Stroke 27 550-558 Sudlow CLM, Warlow CP (1997). Comparable studies of the incidence of stroke and its pathological types. Results from an international collahoration. Stroke 28 491-499... 

Race and sex differences in the distribution of cerebral atherosclerosis. Stroke 27 1974-1980 Wolf PA, D Agostino RB, O Neal MA et al. (1992). Secular trends in stroke incidence and mortality the Framingham Study. Stroke 23 1551-1555... 

Age is the strongest risk factor for ischemic stroke of all subtypes and for primary intracerebral hemorrhage, but it is less important for subarachnoid hemorrhage (Bamford et al. 1990 Rothwell et al. 2005). Overall stroke incidence at age 75-84 is approximately 25 times higher than at age 45-54 (see Fig. 1.2). 

Ascorbic acid has been implicated in many neurological diseases. There is a strong inverse relation between serum vitamin C concentration and stroke incidence... 

TE, Moye LA, Piller LB, Rutherford J, Simpson LM, Braunwald 107. E. Reduction of stroke incidence after myocardial infarction with pravastatin the Cholesterol and Recurrent Events (CARE) study. 108. The Care Investigators. Circulation 1999 99 216-223. 

Further support for using blood pressure as a surrogate endpoint is provided by the concordance of evidence from a number of clinical trials in which blood pressure lowering with low-dose diuretics and P-blockers was shown to reduce the incidence of stroke/ coronary artery disease/ and congestive heart failure in hypertensive patients (19). Of particular interest is a meta-analysis that was conducted to compare the extent of blood pressure reduction achieved in different clinical trials with the maximum benefit that was anticipated on epidemiolgic grounds (Table 17.3) (20). The decrease in stroke incidence anticipated for a 5- to 6-mm Hg average reduction in diastolic blood pressure was fully realized with only 2 to 3 years of antihypertensive therapy. 

Ethnic variations in diet, additives or salt content may alter metabolism rates. Lin et al. (1986) and Henry et al. (1987) report that antipyrine metabolism was different in rural Asian Indians than in Asian Indian immigrants resident in England for some years. Dietary environmental differences may also account for the findings of Gould et al. (1972) andKato etal. (1973) of a gradation ofheart and stroke incidence, lowest in residents of rural Japan, higher in Japanese in Hawaii and highest in Japanese in California. 

Stroke risk is increased above that of the general population in the elderly male individuals and in African-Americans. In addition, geographic disparity in stroke incidence exists, such that several areas of the southeastern United States have stroke mortality rates more than twice that of the national average." This phenomenon, originally describing areas of the coastal Carohnas and Georgia, has been named the Stroke Belt. ... 

In secondary prevention, carotid endarterectomy of an ulcerated and/or stenotic carotid artery is a very effective way to reduce stroke incidence and recurrence in appropriate patients and in centers where the operative morbidity and mortality are low. In fact, in ischemic stroke patients with 70% to 99% stenosis of an ipsilateral internal carotid artery, recurrent stroke risk can be reduced by up to 48% compared with medical therapy alone when combined with aspirin 325 mg daily. In patients in whom the risk of endarterectomy is thought to be excessive, carotid stenting may be effective in reducing recurrent stroke risk but is less invasive. Carotid stenting is still considered investigational, however, and issues remain regarding the optimal methods and patients for this procedure. 

Burchfiel CM, Curb JD, Rodriguez BL et al. Glucose intolerance and 22-year stroke incidence. The Honolulu Heart Program. Stroke 1994 25(5) 951-957. 

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