This is a surprise. Oxford University researchers have done a meta-analysis of 61 international studies of cholesterol and cardiovascular deaths and published their findings in the journal Lancet. The data came from almost 900,000 adults without previous disease who had baseline total cholesterol and blood pressure measurements. There were more than 55,000 cardiovascular deaths over the study period - 34,000 ischemic heart disease (coronary artery disease), 12,000 stroke, and10,000 'other'.

The effects of raised cholesterol on ischemic heart disease mortality were clear-cut, as expected. There was 'dose-dependence', i.e. the greater the cholesterol, the greater the risk of earlier death. The surprise came with the data on stroke. Although total cholesterol was weakly linked to both common types of stroke (ischemic and hemorrhagic) mortality in the 40-60 year-olds, in the older age groups - over 70s - there was no such correlation. In particular, those older folk with a systolic blood pressure over 145 mm Hg had what's called a negative correlation between cholesterol levels and stroke, i.e. the higher the cholesterol the lower the fatal stroke risk.

What to make of these findings? The authors of the analysis have no good answers for the stroke results. They were glad to be able to report, however, that statin drugs "substantially reduce not only coronary event rates but also total stroke rates in patients with a wide range of ages and blood pressure". So until the reasons for the stroke/cholesterol finding are explained, keep taking your statin .