Coronary heart disease and stroke during follow-up

Since the baseline data collection, deaths have been flagged by the Office for National Statistics and we have collected data regarding non-fatal coronary and stroke events during 20 years of follow-up to 2011. 

Coronary heart disease events occurred in 1256(30%) participants, of these 86% were first-ever events.  Fatal Coronary heart disease was the first recorded follow-up event in 159 participants.  Indian Asians were most (Hazard ratio(HR): 1.7), and African Caribbeans least(HR:0.64), at risk of coronary events. 

Stroke events occurred in 401 participants during follow-up, of which 371(93%) were first ever strokes.  Fatal stroke was the first recorded follow-up event in 48 participants.  African Caribbeans had the highest(HR:1.5) and Europeans(HR:1) the lowest rates of stroke.

Analyses of baseline characteristics as predictors of these events have indicated that diabetes and dysglycaemia are particularly toxic in South Asians and African Caribbeans in whom stroke was 2.5-3 times more likely to occur in association with diabetes compared with Europeans (References 17, 18, 24).  This extra diabetes-related ‘toxicity’ was also present, but  to a lesser extent for South Asians in association with incident coronary heart disease, in whom diabetes was associated with a 40% excess risk.  Other measured baseline risk factors did not explain the ethnic differentials in stroke and coronary disease.

Further study of factors acting across the life course, together with genetic and epigenetic studies  could elucidate  mechanisms underlying ethnic differences and define key time points for preventive interventions.  These findings suggest that early glycaemic control plus intervention to control blood pressure in these high risk populations may be paramount in the prevention of stroke and coronary heart disease.