Background The effect of work on blood pressure (BP) relative to a non-working status with appropriate adjustment for confounders is not well defined. High job control has been found to be associated with lower BP and with nocturnal BP dipping. However, with older workers this may be compromised.
Methods A cross-sectional study was carried out on a sample of the Irish general population. In total, 2,047 males and females aged 50-69 years were recruited. Data were collected on socio-demographic factors, medication and clinic BP measurements on workers (n = 1,025) and non-workers (n = 950). A sub-sample of the participants had ambulatory blood pressure monitoring (ABPM) done (n = 1,112). Job control was measured using two scales from the Copenhagen Psychosocial Questionnaire (COPSOQ) – possibility for development and influence at work. Nocturnal systolic blood pressure (SBP) dipping was the reduction in SBP from day to night-time and was calculated using the following formula (1-asleep SBP/awake SBP)*100.
Results Those who were hypertensive on the clinic and ABPM SBP readings tended to be >58 years, male, overweight/obese and taking anti-hypertensive medication. Typically workers were younger, male, had a normal body mass index and had significantly lower clinic SBP than non-workers (p≤0.02). In analysis adjusted for socio-demographic factors, there was a significant difference between workers and non-workers for SBP dipping (OR 1.69 [95% CI 1.13, 2.53], p=0.01), but not for clinic or asleep SBP. When the analysis was stratified by anti-hypertensive treatment, workers were significantly more likely than non-workers to have a high clinic SBP (1.45 [1.00, 2.11]) and SBP dipping (2.07 [1.19, 3.61]). Looking only at workers, those who were on anti-hypertensive treatment with a high possibility for development were three times more likely to be SBP dippers than those with a low possibility for development (p = 0.03). There was no significant association found for influence at work and SBP dipping.
Discussion While workers had higher clinic SBP readings than non-workers they were also more likely to have nocturnal SBP dipping a factor known to be beneficial to cardiovascular health. Furthermore, this study showed that allowing workers to develop their skills in the workplace positively influenced their blood pressure.