Objective  To observe the effects of occupational exposure to polycyclic aromatic hydrocarbons and different blood pressure states on mild cognitive impairment (MCI) of workers, and further analyze their interaction.

  Methods  A total of 610 workers in a coking plant and 454 workers in a water treatment plant in Shanxi were studied. The workers in these two factories were divided into normal blood pressure group, prehypertension group and hypertension group. The personal information of workers was collected, and multiple logistic regression analysis was used to explore whether polycyclic aromatic hydrocarbon exposure and blood pressure status had an interaction on workers' MCI.

  Results  Among 1 064 subjects, 384 cases with MCI were detected, and the totally positive rate was 36.09%, while 40.33% in coking plant and 30.40% in water treatment plant (P < 0.05). Furthermore, there was significant difference of MCI rate among workers with different blood pressure in coking plant (P < 0.05), and the MCI rate also increased with the increase of blood pressure; there was no significant difference of MCI rate among workers with different blood pressure in water treatment plant(P > 0.05). If analysis for each factory, logistic regression analysis showed that the risk of MCI in prehypertensive and hypertensive workers did not increase compared with normotensive workers in coking plant or water treatment plant (P > 0.05). However, if analysis together, the results of logistic regression analysis showed that compared with normal blood pressure group in water treatment plant, simple PAH exposure or simple hypertension were not risk factors for MCI detection, but the PAH exposed workers with hypertension had a higher risk of MCI(OR=1.909, 95% CI: 1.011 - 3.581, P < 0.05).

  Conclusion  There is interaction between blood pressure and occupational PAHs exposure on cognitive function of workers.