Panethnic Differences in Blood Pressure in Europe: A Systematic Review and Meta-Analysis

Abstract

Background: People of Sub Saharan Africa (SSA) and South Asians(SA) ethnic minorities living in Europe have higher risk of stroke than native Europeans(EU). Study objective is to provide an assessment of gender specific absolute differences in office systolic(SBP) and diastolic(DBP) blood pressure(BP) levels between SSA, SA, and EU.

Methods and findings: We performed a systematic review and meta-analysis of observational studies conducted in Europe that examined BP in non-selected adult SSA, SA and EU subjects. Medline, PubMed, Embase, Web of Science, and Scopus were searched from their inception through January 31st 2015, for relevant articles. Outcome measures were mean SBP and DBP differences between minorities and EU, using a random effects model and tested for heterogeneity. Twenty-one studies involving 9,070 SSA, 18,421 SA, and 130,380 EU were included. Compared with EU, SSA had higher values of both SBP (3.38 mmHg, 95% CI 1.28 to 5.48 mmHg; and 6.00 mmHg, 95% CI 2.22 to 9.78 in men and women respectively) and DBP (3.29 mmHg, 95% CI 1.80 to 4.78; 5.35 mmHg, 95% CI 3.04 to 7.66). SA had lower SBP than EU(-4.57 mmHg, 95% CI -6.20 to -2.93; -2.97 mmHg, 95% CI -5.45 to -0.49) but similar DBP values. Meta-analysis by subgroup showed that SA originating from countries where Islam is the main religion had lower SBP and DBP values than EU. In multivariate meta-regression analyses, SBP difference between minorities and EU populations, was influenced by panethnicity and diabetes prevalence.

Conclusions: 1) The higher BP in SSA is maintained over decades, suggesting limited efficacy of prevention strategies in such group in Europe;2) The lower BP in Muslim populations suggests that yet untapped lifestyle and behavioral habits may reveal advantages towards the development of hypertension;3) The additive effect of diabetes, emphasizes the need of new strategies for the control of hypertension in groups at high prevalence of diabetes.

Fig 1. Flow chart of the selection process.

Flow chart of the selection process according to the PRISMA Statement [24].

Fig 2. SBP differences between minority groups and EU participants by panethnicity and gender.

Subgroup comparisons of the weighted mean difference of systolic blood pressure (BP) between minority groups and EU participants by panethnicity and gender. Diamonds denote the pooled estimates and 95% confidence intervals. SSA = Sub-Saharan Africans; SA = South Asians; EU = Europeans, “n” is the number of comparisons available for each subgroup.

Fig 3. DBP differences between minority groups and EU participants by panethnicity and gender.

Subgroup comparisons of the weighted mean difference of diastolic blood pressure (BP) between minority groups and EU participants by panethnicity and gender. Diamonds denote the pooled estimates and 95% confidence intervals. SSA = Sub-Saharan Africans; SA = South Asians; EU = Europeans, “n” is the number of comparisons available for each subgroup.

Fig 4. BP differences between subjects originating from SA countries and EU participants by dominant religion in the country of origin.

Subgroup comparisons of the weighted mean difference of systolic and diastolic blood pressure between South Asians (SA) and European (EU) participants by dominant religion in the country of origin. The term "others" refers to comparisons performed between EU participants and subjects who originated from countries with a different dominant religion. Diamonds denote the pooled estimates and 95% confidence intervals, “n” is the number of comparisons available for each subgroup.

Fig 5. Gender specific meta-regression model.

Women (number of comparisons = 28). Intercept: -8.260 mmHg (-12.167 to -4.352; p<0.001); Ethnicity: 8.695 mmHg (3.751 to 13.640; p = 0.001); Difference in Diabetes Prevalence: 0.543 mmHg (0.207 to 0.880; p = 0.002). Proportion of between-study variance explained (Adjusted R-squared) = 45.81%; joint test for all covariates F = 9.79, p<0.0017. Men (number of comparisons = 31). Intercept: -7.730 mmHg (-10.268 to -5.193; p<0.001); Ethnicity: 8.496 mmHg (5.234 to 11.759); p<0.001); Difference in Diabetes Prevalence: 0.481 mmHg (0.162 to 0.600; p<0.001). Proportion of between-study variance explained (Adjusted R-squared) = 60.73%; joint test for all covariates F = 18.04, p<0.001.