Studies have found little association between cholesterol and overall stroke risk, but this could be attributable to different relations for haemorrhagic and ischaemic stroke. Stroke mortality data from prospective studies cannot usually be divided into stroke subtypes. We have therefore analysed stroke based on hospital admissions, obtained by computerised linkage with acute hospital discharges in Scotland for a large prospective cohort study

Ben-Shlomo, Y.

C. L Hart

Hart, C.

Hawthorne, V.M.

Rodgers, A.

English

PubMed

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Journal of Epidemiology & Community Health

The relation between cholesterol and haemorrhagic or ischaemic stroke in the Renfrew/Paisley study

Hart, C.L.

Hole, D.J.

Davey Smith, G.

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doi:10.1136/jech.54.11.874  2000;54;874-875 J. Epidemiol. Community Health  Carole L Hart, David J Hole and George Davey Smith    or ischaemic stroke in the Renfrew/Paisley studyThe relation between cholesterol and haemorrhagic http://jech.bmj.com/cgi/content/full/54/11/874Updated information and services can be found at:  These include: References http://jech.bmj.com/cgi/content/full/54/11/874#otherarticles6 online articles that cite this article can be accessed at:    http://jech.bmj.com/cgi/content/full/54/11/874#BIBLThis article cites 4 articles, 1 of which can be accessed free at: Rapid responses http://jech.bmj.com/cgi/eletter-submit/54/11/874You can respond to this article at:  serviceEmail alertingtop right corner of the article Receive free email alerts when new articles cite this article - sign up in the box at theTopic collections (694 articles) Stroke   Articles on similar topics can be found in the following collections  Notes    http://www.bmjjournals.com/cgi/reprintformTo order reprints of this article go to:  http://www.bmjjournals.com/subscriptions/ go to: Journal of Epidemiology and Community HealthTo subscribe to  on 14 November 2006 jech.bmj.comDownloaded from Short reportsThe relation between cholesterol and haemorrhagicor ischaemic stroke in the Renfrew/Paisley studyCarole L Hart, David J Hole, George Davey SmithStudies have found little association betweencholesterol and overall stroke risk, but thiscould be attributable to diVerent relations forhaemorrhagic and ischaemic stroke. Strokemortality data from prospective studies cannotusually be divided into stroke subtypes. Wehave therefore analysed stroke based on hospi-tal admissions, obtained by computerised link-age with acute hospital discharges in Scotlandfor a large prospective cohort study.Methods and ResultsThe Renfrew/Paisley study was carried outbetween 1972 and 1976 involving 15 406residents aged 45–64 from the towns ofRenfrew and Paisley.1 The linkage providedrecords of all main diagnoses of stroke in a 20year follow up period. There was no infor-mation on participants having strokes and notbeing admitted to hospital, but with this rela-tively young age group, most would be admit-ted. Blood samples were taken for themeasurement of plasma cholesterol, measuredin mg/dl and converted to mmol/l by multipli-cation by 0.0259. After excluding participantswith missing cholesterol readings, there were6997 men and 8270 women. Cholesterolquintiles were calculated separately for menand women, as women have higher concentra-tions of cholesterol than men.2 Cholesterolgroups were formed by taking each fifth asthe corresponding fifth for men and forwomen.Stroke was defined as ICD8 and ICD9 codes430–438. Haemorrhagic stroke was defined asICD8 codes 430 and 431, and ICD9 codes430–432. It included subarachnoid haemor-rhage and cerebral haemorrhage. Ischaemicstroke was defined as ICD8 codes 432–435and 437, and ICD9 codes 433–435. Ageadjusted stroke rates per 10 000 per year werecalculated using a life table approach andstandardised by five year age groups using theage distribution of the cohort. Cox’s propor-tional hazards models were used to calculatetrends using cholesterol as a continuousvariable and for calculating relative rates withthe lowest fifth as the baseline, and also for cal-culating the relative rates associated with onestandard deviation increase in cholesterol.There were no significant interactions betweencholesterol and sex for each type of stroke, sodata for the men and women were analysedtogether.Table 1 Haemorrhagic and ischaemic stroke rates by cholesterol in men and women aged 45–64 from the Renfrew/Paisleystudy in 20 years of follow upCholesterol quintile (mmol/l)For men <5.08 5.09–5.59 5.60–6.09 6.10–6.68 >6.69 Trend* Relative rate associated with1 standard deviation increasein cholesterolFor women <5.57 5.58–6.09 6.10–6.60 6.61–7.28 >7.29Number of participants 3276 3070 3038 3116 2767All strokeNumber of strokes 199 216 195 209 200Age adjusted rate 45.7 51.1 43.9 45.7 49.4Relative rate† 1 1.10 0.95 0.98 1.07 0.71 0.99(95% CI) (0.90, 1.33) (0.78, 1.16) (0.81, 1.19) (0.88, 1.30) (0.93, 1.05)Relative rate‡ 1 1.05 0.93 0.96 1.01 0.84 0.99(95% CI) (0.86, 1.27) (0.76, 1.13) (0.79, 1.17) (0.83, 1.23) (0.93, 1.06)HaemorrhagicNumber of strokes 23 22 17 23 5Age adjusted rate 4.6 4.9 3.2 4.5 1.1Relative rate† 1 0.97 0.73 0.95 0.23 0.017 0.76(95% CI) (0.54, 1.74) (0.39, 1.36) (0.53, 1.69) (0.09, 0.61) (0.61, 0.95)Relative rate‡ 1 0.92 0.71 0.92 0.22 0.011 0.74(95% CI) (0.51, 1.65) (0.38, 1.34) (0.52, 1.65) (0.08, 0.57) (0.59, 0.94)IschaemicNumber of strokes 50 41 35 50 60Age adjusted rate 11.5 9.3 7.6 11.8 14.5Relative rate† 1 0.85 0.70 0.98 1.35 0.08 1.12(95% CI) (0.56, 1.28) (0.46, 1.08) (0.66, 1.45) (0.93, 1.96) (0.99, 1.28)Relative rate‡ 1 0.82 0.70 0.97 1.30 0.12 1.11(95% CI) (0.54, 1.24) (0.45, 1.07) (0.66, 1.44) (0.89, 1.89) (0.97, 1.26)*Using cholesterol as a continuous variable. †Adjusted for age and sex. ‡Adjusted for age, sex, diastolic blood pressure, height,smoking (cigarettes per day and a 0/1 term for ex-smokers) and pre-existing coronary heart disease (angina, severe chest pain last-ing half an hour or more, or ischaemia on electrocardiogram).J Epidemiol Community Health 2000;54:874–875874Department of PublicHealth, University ofGlasgow, 1 LilybankGardens, GlasgowG12 8RZC L HartWest of ScotlandCancer SurveillanceUnit, Department ofPublic Health,University of GlasgowD J HoleDepartment of SocialMedicine, Universityof BristolG Davey SmithCorrespondence to:Carole Hart(c.l.hart@udcf.gla.ac.uk)Accepted for publication14 July 2000www.jech.com on 14 November 2006 jech.bmj.comDownloaded from There were 1019 participants who had ahospital discharge with a main diagnosis ofstroke, 90 of which were classified as haemor-rhagic and 236 as ischaemic. The majority ofstrokes (693) were thus ill defined. Those withill defined strokes were on average two yearsolder than those with haemorrhagic or ischae-mic strokes but there was no diVerencebetween the sexes. Although there was noapparent relation between cholesterol andoverall stroke, there was a statistically signifi-cant inverse relation between cholesterol andhaemorrhagic stroke (table 1). In contrast, therelation between cholesterol and ischaemicstroke was J shaped with participants in themiddle fifth having the lowest stroke rate andparticipants in the highest fifth having thehighest stroke rate. The diVerence between therelative rates for haemorrhagic and for ischae-mic stroke adjusting for age and sex was statis-tically significant (p=0.004). Relative rates ofstroke were calculated with additional adjust-ment for other risk factors for stroke but thisdid not account for the diVerent associationswith haemorrhagic and ischaemic stroke andhad very little eVect on the relative rates.CommentThere have been few studies examining theassociation between cholesterol and strokesubtype, although the limited data availablesuggest cholesterol is positively related toischaemic stroke and inversely related tohaemorrhagic stroke.3 4 This is particularlyclear in eastern Asia where haemorrhagicstroke is more common than in western Europeand North America.4 Cholesterol concentra-tions are lower in eastern Asia than in thisstudy. Randomised trials of cholesterol lower-ing with statins show reductions in overallstroke incidence and no increase in haemor-rhagic stroke, although power to detect the lat-ter is limited in studies completed to date.5 Theobservational inverse association of cholesteroland haemorrhagic stroke risk may be non-causal and in populations where ischaemicstroke is considerably more common thanhaemorrhagic stroke the overall benefits ofcholesterol lowering are clear.Funding: this study was provided with grants from Chest, Heartand Stroke Scotland, and the Stroke Association.Conflicts of interest: none.1 Hawthorne VM, Watt GCM, Hart CL, et al. Cardiorespira-tory disease in men and women in urban Scotland: baselinecharacteristics of the Renfrew/Paisley (Midspan) Studypopulation. Scott Med J 1995;40:102–7.2 Hart C, Davey Smith G, Hole D. Risk factors and 20 yearstroke mortality in men and women in the Renfrew/Paisleystudy in Scotland. Stroke 1999;30:1999–2007.3 Ben-Shlomo Y,Neaton J,Wentworth D, et al. Serum choles-terol and mortality from haemorrhagic and non-haemorrhagic stroke: 16 year follow up of a third of a mil-lion men screened for the Multiple Risk FactorIntervention Trial. [Abstract]. J Epidemiol CommunityHealth 1998;52:683–4.4 Rodgers A,MacMahon S, Yee T, et al. Blood pressure, chol-esterol, and stroke in eastern Asia.Lancet 1998;352:1801–7.5 Evans SN, Fotherby MD. Cholesterol and stroke.Reviews inClinical Gerontology 1999;9:1–12.Relation between cholesterol and haemorrhagic or ischaemic stroke 875www.jech.com on 14 November 2006 jech.bmj.comDownloaded from 

3 Ben-Shlomo Y,Neaton J,Wentworth D,et al.Serum cholesterol and mortality from haemorrhagic and nonhaemorrhagic stroke: 16 year follow up of a third of a million men screened for the Multiple Risk Factor Intervention Trial.

Blood pressure, cholesterol,and stroke in eastern Asia.Lancet

Cardiorespiratory disease in men and women in urban Scotland:baseline characteristics of the Renfrew/Paisley (Midspan) Study population.

Cholesterol and stroke. Reviews in Clinical Gerontology 1999;9:1–12. Relation between cholesterol and haemorrhagic or ischaemic stroke 875 www.jech.com on 14

Community Health

Risk factors and 20 year stroke mortality in men and women in the Renfrew/Paisley study in Scotland. Stroke

The relation between cholesterol and haemorrhagic or ischaemic stroke in the Renfrew/Paisley study

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