Cardiac autonomic function ‘worse in Indian Asians than Europeans’
MedWire News: Indian Asians show marked impairments in cardiac autonomic function compared with their European counterparts, a study has found.
The researchers suggest that these differences may contribute to the observed disparity in hyperglycemia and vascular disease prevalence between the ethnic groups.
Nishi Chaturvedi (National Heart and Lung Institute, London, UK) and team sought to explain why, at a general population level, Indian Asians have a greater risk for diabetes and coronary heart disease (CHD) than Europeans.
Their study participants were obtained from the London Life Science Prospective Population Study (LOLIPOP), a multi-ethnic, population-based study of more than 25,000 men aged 35–75 years and women aged 55–57 years recruited from primary care.
In all, 149 Europeans and 151 Indian Asians (Punjabi Sikh) were identified from the LOLIPOP cohort; in both groups the mean age was 62 years and around two-thirds were male. Several other characteristics were equivalent between the groups, including mean blood pressure, body mass index, and the prevalence of coronary heart disease and metabolic syndrome.
Importantly, however, there were also notable differences between the ethnic groups. Diabetes was more prevalent in Indian Asians than Europeans (27.2% vs 7.4%), while other indicators of hyperglycemia and insulin resistance were more adverse.
Several measures of cardiac autonomic function also differed significantly between the groups. For instance, Indian Asians had shorter mean RR intervals (969 vs 1022 ms), lower total RR interval power (925 vs 1075 ms2), and lower baroreflex sensitivity (5.7 vs 66 ms/mmHg).
All measures of cardiac autonomic dysfunction were significantly associated with hyperglycemia; ethnic differences in cardiac autonomic function persisted after adjustment for age, blood pressure, and medication, but were attenuated or abolished after adjustment for glycated hemoglobin or hyperglycemia.
Writing in the journal Diabetologia, Chaturvedi et al conclude: “Impaired cardiac autonomic function may be a strong candidate to explain the greater risk of CHD and also the greater impact of hyperglycemia on CHD in Indian Asians compared with Europeans.
“As autonomic function improves on correction of hyperglycemia, even in the non-diabetic state, this represents an important interventional target when attempting to reduce the burden of cardiometabolic disease in Indian Asians.”
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By Joanna Lyford