Workplace-based primary prevention intervention reduces incidence of hypertension: a post hoc analysis of cluster randomized controlled study
Authors: Hu Zhen , Wang Xin , Hong Conglin , Zheng Congyi , Zhang Linfeng , Chen Zuo , Zhou Haoqi , Tian Yixin , Cao Xue , Cai Jiayin , Gu Runqing , Tian Ye , Shao Lan , Wang Zengwu 
Published: June 2023

Abstract
Background
A workplace-based primary prevention intervention be an effective approach to reducing the incidence of hypertension (HTN). However, few studies to date have addressed the effect among the Chinese working population. We assessed the effect of a workplace-based multicomponent prevention interventions program for cardiovascular disease on reducing the occurrence of HTN through encouraging employees to adopt a healthy lifestyle.

Methods
In this post hoc analysis of cluster randomized controlled study, 60 workplaces across 20 urban regions in China were randomized to either the intervention group (n = 40) or control group (n = 20). All employees in each workplace were asked to complete a baseline survey after randomization for obtaining sociodemographic information, health status, lifestyle, etc. Employees in the intervention group were given a 2-year workplace-based primary prevention intervention program for improving their cardiovascular health, including (1) cardiovascular health education, (2) a reasonable diet, (3) tobacco cessation, (4) physical environment promotion, (5) physical activity, (6) stress management, and (7) health screening. The primary outcome was the incidence of HTN, and the secondary outcomes were improvements of blood pressure (BP) levels and lifestyle factors from baseline to 24 months. A mix effect model was used to assess the intervention effect at the end of the intervention in the two groups.

Results
Overall, 24,396 participants (18,170 in the intervention group and 6,226 in the control group) were included (mean [standard deviation] age, 39.3 [9.1] years; 14,727 men [60.4%]). After 24 months of the intervention, the incidence of HTN was 8.0% in the intervention groups and 9.6% in the control groups [relative risk (RR) = 0.66, 95% CI, 0.58 ~ 0.76, P < 0.001]. The intervention effect was significant on systolic BP (SBP) level (β =  − 0.7 mm Hg, 95% CI, − 1.06 ~  − 0.35; P < 0.001) and on diastolic BP (DBP) level (β =  − 1.0 mm Hg, 95% CI, − 1.31 ~  − 0.76; P < 0.001). Moreover, greater improvements were reported in the rates of regular exercise [odd ratio (OR) = 1.39, 95% CI, 1.28 ~ 1.50; P < 0.001], excessive intake of fatty food (OR = 0.54, 95% CI, 0.50 ~ 0.59; P < 0.001), and restrictive use of salt (OR = 1.22, 95% CI, 1.09 ~ 1.36; P = 0.001) in intervention groups. People with a deteriorating lifestyle had higher rates of developing HTN than those with the same or improved lifestyle. Subgroup analysis showed that the intervention effect of BP on employees with educational attainment of high school above (SBP: β =  − 1.38/ − 0.76 mm Hg, P < 0.05; DBP: β =  − 2.26/ − 0.75 mm Hg, P < 0.001), manual labor workers and administrative worker (SBP: β =  − 1.04/ − 1.66 mm Hg, P < 0.05; DBP: β =  − 1.85/ − 0.40 mm Hg, P < 0.05), and employees from a workplace with an affiliated hospital (SBP: β =  − 2.63 mm Hg, P < 0.001; DBP: β =  − 1.93 mm Hg, P < 0.001) were significantly in the intervention group.

Conclusions
This post hoc analysis found that workplace-based primary prevention interventions program for cardiovascular disease were effective in promoting healthy lifestyle and reducing the incidence of HTN among employees.

Trial registration
Chinese Clinical Trial Registry No. ChiCTR-ECS-14004641.