Job strain and physiological stress responses in nurses and nurse's aides: predictors of daily blood pressure variability.

BACKGROUND: Job strain has been implicated in risk of cardiovascular disease, and there is evidence for increased blood pressure among men with job strain. It is unclear, however, to what degree job strain affects blood pressure in women. This study examined the relationships between job strain, norepinephrine and epinephrine excretion in the workplace, and ambulatory blood pressure variability during waking hours in women working as nurses or nurse's aides in Hilo, Hawaii.
METHODS: Women from two ethnic groups, Filipino-Americans (n = 36) and Euro-Americans (n = 23), were measured on a workday, urinary catecholamine excretion and ambulatory blood pressure being measured over a 4-h period at work and home, and overnight over an 8-h period. The rates of catecholamine excretion were measured in timed urine samples using high-performance liquid chromatography with electrochemical detection, and ambulatory blood pressure was measured at 15-min intervals using a SpaceLabs 90207 monitor. The women filled out the Job Content Questionnaire prior to the physiological measurements.
RESULTS: Scores on the Job Content Questionnaire were not significantly associated with the physiological measures, although correlations were higher for Euro-American participants than Filipino-Americans. Catecholamine excretion rates in the workplace were significantly related to blood pressure variability throughout the day and to systolic blood pressure means, but catecholamine excretion rates in other daily settings were not significantly related to blood pressure.
CONCLUSIONS: These results support the idea that stress in the workplace has special significance for the prediction of cardiovascular health risk, and that catecholamine excretion at work is significantly associated with increased blood pressure variability during the day. Job strain, as measured by subscales from the Job Content Questionnaire, was not associated with any of the physiological measures. This lack of association may be the result of ethnic and circumstantial bias in the questionnaire, suggesting that job strain should be evaluated in a more critical manner in populations differing from the ones in which the concept was developed.