Hypertension Risk in Coal Miners after Healthy Hire Effect Elimination

Healthy hire effect (HHE) is considered as an epidemiological phenomenon, complicating the assessment of a true cause - effect relationship between occupational exposure and health status of workers. The current study was aimed at identification and elimination of HHE in the risk assessment of arterial hypertension (AH) in coal miners. Overall, 1553 miners, working in West Siberia, were enrolled in the cross-sectional cohort study of risks for AH, the control group included 2266 subjects from other industrial sectors. The HHE identification was carried out with RR values in the age groups. A method of HHE elimination designed with analytical age-adjustment of hypertension rate in the studied group with the subsequent recalculation of the RR was implemented and tested. Initial data suggested a low risk of hypertension development in coal miners (RR = 0.58, 95 % CI 0,53:0,64) compared to workers of other industrial sectors. Elimination of HHE resulted in an increase of risk for hypertension in coal miners (RR = 1.11, 95 % CI 1,04:1,19). HHE reports that the health status of subjects, employed in the coal industry sector, is better compared to the other working population, resulting in lower incidence of hypertension. The application of the HHE elimination method resulted in the opposite results of professional affiliation impact on the incidence of hypertension compared to the initial data.