This study aimed to investigate the prevalence of pre-hypertension among respondents from three study sites (Kano, Ilorin, and DRC), as well as to explore the associations between pre-hypertension and various sociodemographic factors, BMI, and dietary inflammatory index (DII). The prevalence of prehypertension in the study was high at 56.3% and 48.4% of the respondents had high dietary inflammatory index. However, we found no relationship between the dietary inflammatory index and prehypertension. Advanced age and high BMI were the independent predictors of prehypertension in this study.
The prevalence of pre-hypertension in this study is similar to 58.7% and comparable to 49.6% reported in Sokoto and Ilorin, northwestern and northcentral Nigeria respectively.29,30 However, it is higher than what has been reported in some other studies. For example, a systematic review and meta-analysis in Nigeria reported a pre-hypertension prevalence of 30.9% among urban adults,8 a national survey in Uganda reported a prevalence of 38.8%,31 a population-based study in DRC reported a prevalence of 11.4%,32 and large community-based study in central China reported a prevalence of 42.7%.33 This could be due to the differences in the sample size with these studies having larger sample sizes as compared to our study. The higher prevalence observed in Ilorin (78.3%) compared to other sites could be due to regional variations in lifestyle and genetic predispositions.30
Nearly half (48.4%) of respondents had a high DII, indicating a pro-inflammatory diet. This is similar to the findings from numerous studies.16,17,35–37 This kind of diet increases the prehypertension and hypertension risk factors like obesity and being frail in the future.17,18 A South African study stated that those in urban areas had a high energy and high-fat diet which are pro-inflammatory compared to those in rural areas.38 This finding is comparable since our study was conducted in the urban settings.
Age, ethnicity, study site, and BMI were significantly associated with pre-hypertension, with age and BMI being independent predictors. Younger respondents (18–40 years) were 75% less likely to develop pre-hypertension, and underweight individuals were 74% also less likely to have pre-hypertension. Previous studies also found significant associations between increasing age and higher BMI with elevated blood pressure levels, which is consistent with our findings.1–4, 8,11,14
Interestingly, no association was found between DII and pre-hypertension. This is similar to the findings of a systematic review and meta-analysis in China,38 and among Japanese man,39 older adults in Taiwan,40 and US adults.41 In contrast, several studies have suggested that a pro-inflammatory diet can contribute to the development of hypertension.15,20,34,36 This discrepancy could be due to differences in dietary assessment methods, or the specific population studied.
There are several limitations to this study that should be acknowledged. The cross-sectional design limits the ability to establish causality between the identified risk factors and pre-hypertension. Additionally, the study's reliance on self-reported data for some variables may introduce reporting bias. The sample size, while adequate for initial analysis, may not be large enough to detect all potential associations, particularly for sub-group analyses. Furthermore, the study did not account for other potential confounding factors such as physical activity levels, dietary habits beyond DII, and genetic predispositions.
Future research should aim to address the limitations identified in this study. Longitudinal studies would be beneficial to establish causal relationships between sociodemographic factors, BMI, dietary patterns, and pre-hypertension. Additionally, exploring the impact of interventions targeting weight management and dietary modifications on blood pressure levels in this population could provide valuable insights for public health strategies.