The impact of dietary and lifestyle interventions on blood pressure management in sub-Saharan Africa: a systematic review and metanalysis

Abstract

Objectives: Current literature is lacking a comprehensive review of data on dietary interventions in blood pressure (BP) management in sub-Saharan African countries. We assessed the association of dietary and other lifestyle interventions with BP-lowering effects in populations within sub-Saharan Africa.

Methods: We performed a systematic review and random-effects meta-analysis to determine the impact of dietary and lifestyle interventions on SBP and DBP in sub-Saharan Africa. We searched the MEDLINE, EMBASE, and Web of Science databases. We included intervention studies that were randomized and nonrandomized conducted in Africans residing in sub-Saharan Africa investigating diet and other lifestyle, physical activity, weight loss, tobacco, and alcohol cessation modifications. We determined the effect of diet and other lifestyle interventions on SBP and DBP. We expressed effect size as weighted mean difference and 95% confidence interval (CI).

Main results: : We identified six studies with a total of 1412 individuals, 38% males, mean age of 52.8 years (SD = 11.5). The weighted mean difference of dietary and other lifestyle interventions on SBP and DBP was -7.33 mmHg, (95% CI: -9.90 to -4.76, P < 0.001) and -2.98 mmHg, (95% CI: -4.28 to -1.69, P < 0.001), respectively. In the metaregression analyses, the duration of the interventions did not have any effect on changes in SBP and DBP.

Principal conclusion: : Dietary modifications showed a beneficial overall improvement in SBP and DBP in Africans. However, aside from low-salt interventions, studies on dietary potassium, healthy dietary patterns, and lifestyle modifications have not been investigated extensively in Africans and are in critical need. In addition, researchers will need to consider the settings (rural, urban, or semiurban) and the predominant existing dietary habits while designing studies on dietary interventions in sub-Saharan Africa.

Prospero registration: CRD42020207923.

FIGURE 1

Process of study selection for the meta-analysis on the impact of dietary and lifestyle interventions on blood pressure management in sub-Saharan Africa. This figure shows the process of study selection for the meta-analysis of the impact of dietary and lifestyle interventions on blood pressure in sub-Saharan Africa: study selection for meta-analysis shows the identification, screening, eligibility, and inclusion of participants.

FIGURE 2

Mean difference and standard errors for the net effect of dietary and other lifestyle interventions on SBP (meta-analysis). The mean differences in SBP and 95% confidence intervals and standard errors are shown for the intervention and control groups for the populations analyzed in the meta-analysis. First, results are reported in mmHg. Horizontal lines are reported as 95% confidence interval. Second, studies (1) and (2) by Siervo are the same study with two intervention groups [17], include two groups (high-nitrate beetroot juice with folic acid (1) and high-nitrate beetroot juice without folic acid (2). Third, Chi², chi-square statistic; CI, confidence interval; df, degree of freedom; I², I-square heterogeneity statistic; IV, weighted mean difference; SE, standard error of treatment Effect; Tau², between-study variance; TE, treatment effect.

FIGURE 3

Mean difference and standard errors for the net effect of dietary and other lifestyle interventions on DBP (meta-analysis). The mean differences in DBP and 95% confidence intervals and standard errors are shown for the intervention and control groups for the populations analyzed in the meta-analysis. First, results are reported in mmHg. Horizontal lines are reported as 95% confidence interval. Second, studies 1 and 2 by Siervo are the same study with two intervention groups [17], include two groups (high-nitrate beetroot juice with folic acid (1) and high-nitrate beetroot juice without folic acid (2). Third, Chi², chi-square statistic; CI, confidence interval; df, degree of freedom; I², I-square heterogeneity statistic; IV, weighted mean difference; SE, standard error of treatment effect; Tau², between-study variance; TE, treatment effect.