High prevalence of hypertension and high-normal blood pressure: findings from a large population-based survey of young adults in Zimbabwe

Background Most cardiovascular mortality is due to hypertension and onset may be in youth. We investigated the prevalence of and risk factors for elevated blood pressure (BP) (hypertension (≥140/90mmHg) and high-normal BP (130-139/85-89mmHg)) among youth in Zimbabwe. Methods A population-based survey of randomly sampled 18-24 year olds from 24 communities in three provinces was conducted, with standardised questionnaires to collect socio-demographic, behavioural and clinical data. Height, weight and BP were recorded. The association of potential risk factors with elevated BP was examined using multivariable logistic regression. Findings Of 17,682 participants recruited (98% of those eligible), 17,637 had complete data. The median age was 20 (IQR: 19-22) years and 60.7% were female. After excluding pregnant women (N=754), the prevalence of hypertension and high-normal BP was 7.4% (95% CI:7.0-7.8) and 12.2% (95% CI:12.7-13.7), respectively. Prevalence of hypertension was higher in men (8.7% (95% CI:8.2-9.6) vs 6.6% (95% CI:6.0-6.9) in men and women, respectively) but with age increased to equivalent levels among women (at 18y 7.3% (95% CI:6.2-8.6) and 4.3% (95% CI:3.5-5.2); at 23-24 years 10.9% (95% CI:9.3-12.5) and 9.50% (95% CI:8.4-10.7) in men and women, respectively). After adjusting for confounders, male sex ((aOR) 1.53 (95% CI:1.36-1.74)), increasing age (19-20 years aOR:1.20 (1.00-1.44); 21-22 years aOR:1.45 (95% CI 1.20-1.75); 23-24 years aOR 1.90 (95% CI:1.57-2.30), vs 18 years) and obesity (aOR 1.94 (95% CI:1.53-2.47)) were associated with hypertension. Being underweight (aOR 0.79 (0.63-0.98)) and living with HIV (aOR 0.71 (95% CI:0.55-0.92)) were associated with lower odds of hypertension. Interpretation Prevalence of elevated BP is high among youth in SSA and rises rapidly with age. Further research is needed to understand drivers of BP elevation and the extent of target organ damage in youth in SSA, to guide implementation of prevention and management strategies. Funding Wellcome Trust. ### Competing Interest Statement RAF's institution received a grant from the Wellcome Trust.Salary support for VS and RH was in part from a grant from the Medical Research Council (MRC) and the Department for International Development (DFID UK) under the MRC/DFID Concordat (MR/K012126/1). All other authors declare no competing interests. ### Funding Statement The funder of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the report. KS, TB, RAF and VS had full access to all data. KS had final responsibility for the decision to submit for publication. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the Medical Research Council, Zimbabwe, the Biomedical Research and Training Institute Institutional Review Board and the ethics committee of the London School of Hygiene and Tropical Medicine. Participants viewed an information video about the study (in either English, Shona or Ndebele) on a tablet. Consent was documented electronically on a tablet, with participants retaining a signed paper copy for their records. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Individual, anonymized participant data and a data dictionary will be available through the LSHTM repository (Data Compass) 12 months after publication of trial results. Data will be available to anyone for further analyses with approval from the Medical Research Council of Zimbabwe.