Rapid Responses to:
|
|
Rapid Responses: Rapid Responses published:
-
![[Read Rapid Response]](/icons/misc/sectionDOWN.gif)
The Japanese comparison
- Malcolm E Kendrick (9 June 2006)
-
Lumping 'Apples and Oranges'?
- Bruce Ovbiagele (14 June 2006)
-
Passive smoking
- ANDREW MONTGOMERY (30 June 2006)
-
Cholesterol, stroke, and age
- Anton J.M. de Craen, Gerard J. Blauw and Rudi G.J. Westendorp (4 July 2006)
|
|
|||
|
Malcolm E Kendrick, General Practitioner Benchill Medical Centre, 127 Woodhouse Lane, Wythenshawe M22 7WP
Send response to journal:
|
Yet again, a potential relationship between low cholesterol levels and haemorrhagic stroke is dismissed. Yet again, a causal relationship between high cholesterol levels, ischaemic stroke and CHD is (apparently) confirmed. Yet data from Japan directly contradicts their conclusions. From 1958 to 1995 fat consumption increased from 5% to 20% of the total daily energy consumption, and cholesterol levels rose from 3.9mmol/l to 5.0mmol/l (1). During this period the rate of stroke (combined) fell from 1344/100,000/year to 205/100,000/year. (Age group 60 - 69). This is a 6.5 fold reduction in the rate of stroke (2). (There was also a decrease in death rate from CHD) The possiblity that increased fat consumption was the causal factor in reducing the rate of stroke is strongly supported by a study in Stroke (3), which concluded that: 'A high consumption of animal fat and cholesterol was associated with a reduced risk of cerebral infarction death.' The fact is that a low cholesterol level has been found to be associated with an increased risk of haemorrhagic stroke in many different studies. And when cholesterol levels rose dramatically in Japan the rate of stroke fell off the side of a cliff. A low cholesterol level may well be a 'causal' risk factor for haemorrhagic stroke, and the connection cannot be dismissed by this study. 1:Adachi H, Hino A. Trends in nutritional intake and serum cholesterol levels over 40 years in Tanushimaru, Japanese men. J Epidemiol. 2005 May;15(3):85-9. 2: Longjian Liu, MD, MSc, PhD; Katsumi Ikeda, PhD Yukio Yamori, MD, PhD 'Changes in Stroke Mortality Rates for 1950 to 1997. A Great Slowdown of Decline Trend in Japan.'Stroke. 2001;32:1745 3: Catherine Sauvaget, Jun Nagano, Mikiko Hayashi, Michiko Yamada. 'Animal Protein, Animal Fat, and Cholesterol Intakes and the Risk fo Cerebral Infarction Mortality in the Adult Health Study.' Stroke 2004;35:1351. Competing interests: I am a member of the international network of cholesterol skeptics (THINCS) |
|||
|
|
|||
|
Bruce Ovbiagele, Assistant Professor Stroke Center and Department of Neurology, UCLA School of Medicine, Los Angeles, CA 90095
Send response to journal:
|
The statement by Ebrahim et al,[1] that “…preventive strategies that include lowering blood cholesterol should not be tempered because of concerns about a possible increased risk of hemorrhagic stroke” is too general and does not acknowledge that their study population did not include symptomatic vascular disease patients, the population most often aggressively statin-treated, with resultant low cholesterol levels. These patients frequently have cerebral vessels diseased with atherosclerosis, and evidence of silent cerebral infarcts.[2] Indeed, the only randomized trial to evaluate an intensive statin treatment strategy in primarily ischemic stroke patients noted a higher incidence of hemorrhagic stroke among those who received the high dose statin,[3] and in another study there was a trend towards increased hemorrhagic stroke with statin use among those who had a prior cerebrovascular event.[4] Another limitation of their study is the lack of information on low density liproprotein cholesterol levels, the primary treatment target in guideline recommendations.[5] References: 1. Ebrahim S, et al. Serum cholesterol, haemorrhagic stroke, ischaemic stroke, and myocardial infarction: Korean national health system prospective cohort study. BMJ. 2006 2. Uekita K, Hasebe N, Funayama N, et al. Cervical and intracranial atherosclerosis and silent brain infarction in Japanese patients with coronary artery disease. Cerebrovasc Dis. 2003;16:61-8 3. Welch M et al. The Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL) Study. 15th European Stroke Conference; May 16 -19, 2006; Brussels, Belgium. 4. Collins R, et al; Heart Protection Study Collaborative Group. Effects of cholesterol-lowering with simvastatin on stroke and other major vascular events in 20536 people with cerebrovascular disease or other high -risk conditions. Lancet. 2004 Mar 6;363:757-67. 5. Executive Summary of The Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, And Treatment of High Blood Cholesterol In Adults (Adult Treatment Panel III). Jama. 2001;285:2486-97. Competing interests: None declared |
|||
|
|
|||
|
ANDREW MONTGOMERY, locum practitioner Auckland
Send response to journal:
|
This response is not specific to this article. There have been numerous studies on the putative relation between alcohol consumption and cardiovascular disease. I have, of course, not read them all. That said I have yet to read any that explore the pathological synergy that must exist between alcohol consumption and passive smoking. The colder the climate the more likely it is that those who are heavy consumers of alcohol are also heavy passive smokers. The reasons for this are obvious and should not require elaboration. I look forward to research that controls for this major confounding variable - not just with respect to cardiovascular disease, but also with regard to malignancies of the upper airway and digestive tract. Competing interests: None declared |
|||
|
|
|||
|
Anton J.M. de Craen, epidemiologist Leiden, 2300 RC, The Netherlands, Gerard J. Blauw and Rudi G.J. Westendorp
Send response to journal:
|
Ebrahim and colleagues report whether levels of blood cholesterol are predictive for haemorrhagic and ischaemic stroke in a large cohort of young- and middle-aged Korean civil servants [1]. They found that low levels of cholesterol were associated with haemorrhagic stroke while high levels of cholesterol were associated with ischaemic stroke. Incidence of stroke rises sharply with increasing age. The overwhelming majority of all strokes occur in subjects aged 70 years and over. The mean age of the participants in this study was about 42 years (SD 9 years). This means that 95% of study participants was under 60 years at baseline and therefore under 70 at end of follow up. This is important since the predictive value of total cholesterol for cardiovascular mortality is heavily dependent on age. After age 70 there appears to be no association with cardiovascular mortality [2] while after age 80 high total cholesterol might even be beneficial [3,4]. A similar pattern with age probably also holds for cholesterol and risk of stroke [5]. We agree with the authors that “…the burden of stroke is becoming greater as the population ages, making its prevention a priority”. However, in this case it is not possible to simply transpose the findings from young- and middle-aged people to the elderly population at risk. Therefore, the study by Ebrahim et al does not contribute significant knowledge whether total cholesterol is a risk factor for the vast majority of strokes. Anton JM de Craen, Gerard J Blauw, Rudi GJ Westendorp. Department of Gerontology and Geriatrics, Leiden University Medical Centre. (1) Ebrahim S, Sung J, Song YM, Ferrer RL, Lwalor DA, Davey Smith G. Serum cholesterol, haemorrhagic stroke, ischaemic stroke, and myocardial infarction: Korean national health system prospective cohort study. BMJ 2006;333:22-27. (2) Shipley MJ, Pocock SJ, Marmot MG. Does plasma cholesterol concentration predict mortality from coronary heart disease in elderly people? 18 year follow up in Whitehall study. BMJ 1991;303:89-92. (3) Weverling-Rijnsburger AWE, Blauw GJ, Lagaay AM, Knook DL, Meinders AE, Westendorp RGJ. Total cholesterol and risk of mortality in the oldest old. Lancet 1997;350:1119-1123. (4) Schatz IJ, Masaki K, Yano K, Chen R, Rodriguez BL, Curb JD. Cholesterol and all-cause mortality in elderly people from the Honolulu Heart Program: a cohort study. Lancet 2001;358:351–355. (5) Simons LA, Simons J, Friedlander Y, McCallum J. Cholesterol and other lipids predict coronary heart disease and ischaemic stroke in the elderly, but only in those below 70 years. Atherosclerosis 2001;159:201- 208. Competing interests: None declared |
|||