Aerobic exercise reduces biomarkers related to cardiovascular risk among cleaners: effects of a worksite intervention RCT

PURPOSE Blue-collar workers have an increased risk of cardiovascular disease. Accordingly, elevated levels of biomarkers related to risk of cardiovascular disease, such as high-sensitive C-reactive protein, have been observed among blue-collar workers. The objective was to examine whether an aerobic exercise worksite intervention changes the level of inflammation biomarkers among cleaners. METHODS The design was a cluster-randomized controlled trial with 4-month worksite intervention. Before the 116 cleaners aged 18-65 years were randomized, they signed an informed consent form. The reference group (n = 59) received lectures, and the aerobic exercise group (n = 57) performed worksite aerobic exercise (30 min twice a week). Levels of biomarkers (high-sensitive C-reactive protein, fibrinogen, cholesterol, low- and high-density lipoprotein cholesterol and triglyceride) were collected at baseline and after 4 months. A repeated-measure, multi-adjusted, mixed-model intention-to-treat analysis was applied to compare between-group differences. The study was registered as ISRCTN86682076. RESULTS Significant (p < 0.05) between-group reductions from baseline to follow-up were found for high-sensitive C-reactive protein (-0.54 ± 0.20 µg/ml; 95% CI -0.94, -0.14), low-density lipoprotein cholesterol (-0.32 ± 0.11 mmol/L; 95% CI -0.54, -0.10) and the ratios of LDL/HDL (-0.30 ± 0.08; 95% CI -0.46, -0.14), and LDL/TC cholesterol (-0.04 ± 0.02; 95% CI -0.07, -0.01). CONCLUSION This study indicates that an aerobic exercise intervention among cleaners leads to reduced levels of high-sensitive C-reactive protein and low-density lipoprotein cholesterol, and an unaltered level of fibrinogen. The aerobic exercise seems to improve inflammatory levels and lipoprotein profile among cleaners, with no signs of cardiovascular overload.