Background South Asians have an increased risk of stroke and coronary heart disease (CHD) compared to white European populations. High blood pressure (BP) is an important risk factor for CHD and higher diastolic BP has previously been reported in both South Asian adults and children. Our aim was to examine whether maternal pregnancy, social and lifestyle characteristics are associated with BP at age 4/5 and contribute to these differences.

Methods Born in Bradford is a prospective study of children born to 12 453 mothers between 2007 and 2010 in Bradford, UK. All mothers completed an oral glucose tolerance test in pregnancy and provided detailed social and lifestyle data. We present data from 2129 White British and 2528 Pakistani mother/offspring pairs from the Born in Bradford study. Associations of BMI, gestational diabetes (GD), fasting and post load glucose, maternal hypertension (HDP), smoking in pregnancy and maternal education with offspring systolic and diastolic BP at age 4/5 were examined. We adjusted our results for sex and age at BP measurement.

Results Pakistani children had lower systolic (mean difference −0.16 95% CI −0.79, 0.47) but higher diastolic (mean difference 1.38 95% CI 0.74, 2.03) compared to White British children. In Pakistani children maternal BMI and HDP were strongly associated with higher systolic and diastolic BP but the effect was minimal and weak in White British children. Associations of maternal glucose and BP were consistent with the null hypothesis in both groups. Smoking and education were not associated with BP in either group.

Conclusion Ethnic differences in systolic and diastolic BP are present in children at age 4/5. Consistent with findings in adults, Pakistani origin children have on average lower systolic and higher diastolic BP compared to White British children. Maternal BMI and HDP influence BP in Pakistani children but have minimal effect in White British children. These results suggest a role for some maternal pregnancy and lifestyle exposures in ethnic differences in systolic and diastolic BP at age 4/5.