As the British Heart Foundation National Heart Month draws to a close Lifestyle Elf and I were discussing their blog on heart attacks not being reduced in people taking vitamins and antioxidants which led to us to thinking about the relationship between stress and cardiovascular disease (CVD). Our colleagues in the Pittsburgh Health Heart Project (PHHP) have published, in Psychosomatic Medicine, the next installment of their cohort study looking at daily psychological demands and the progression of carotid artery stenosis.
The PHHP is a prospective epidemiological study designed to examine the role of psychosocial characteristics in the development of subclinical CVD in an initially healthy sample (aged 50-70 years). They used the ecological momentary assessment (EMA) which allows a ‘here and now’ description of what is happening for the patient. They have found that higher task demand (working hard, working fast or juggling several tasks at once) is associated with a significant progression in carotid artery intima-media thickness (IMT) if in employment.
There were initially 340 healthy participants in the PHHP. 270 of these had data at baseline and at 6 year follow up (retention rate of 79%). Of these 54% were women and 14% non-white. Exclusions were made if people had a history of long-term medical disorder, hypertension or treatment for hypertension or hypercholesterolaemia, either prior or during the study.
Self-measured ambulatory blood pressure (ABP) and the EMA were completed every 45 minutes of waking hours for 3 day periods; twice at baseline and once at 6 years. The EMA asks questions relating to experience within the past 10 minutes, including task demand (i.e. “juggling several tasks at once?”) and task choice and decisional choice (i.e.“could change activity if you chose to?”)
Carotid artery IMT and plaque in the carotid arteries was assessed by ultrasound at baseline and at 6-year follow up and finally medical diagnoses and medication use were assessed at baseline, 6 months, 18 months, 30 months, 3 years and 6 years.
Of the 264 on whom employment data was available at follow up, 36% reported working (full or part time). In this aging sample task demand reduced significantly over the 6 years and task control only increased in those who had stopped working at follow up.
In those not treated with antihypertensive drugs there was significant increase in ABP over the 6 years and task demand was significantly associated with plaque progression and IMT progression.
Task control was not associated with IMT nor with plaque progression in the sample as a whole.
Atherosclerotic plaques increased in number and IMT progressed the most amongst the older male population.
Waist circumference was found to have a significant effect on IMT progression but clinic BP, current smoking status, glucose and insulin, and HDL cholesterol were unrelated to the progression of disease, irrespective of medication history.
The authors concluded that:
Among healthy adults with no exposure to antihypertensive medication, perceived daily psychological demands are associated with subclinical atherosclerosis progression at 6 years
As an Elf it would appear that it is not whether you have choice of activity that affects the risk of atherosclerosis but how much work you have to do at any one time and that a rise in blood pressure appears to mediate this.
This cohort study has managed to retain a good quantity of participants across a time where people often move from employment to retirement. The use of a ‘here and now’ assessment of psychological demand reduces the possibility of memory distortion in reporting stress levels. The regimen used here may be too much work for most, however it suggests that a regular diary of symptoms could provide clinicians a clear idea of how patients can reduce stress levels in their lives.
Lifestyle Elf and I are very happy to be out here in the Woodlands sharing the workload with the rest of the National Elf Service, so reducing our risk of developing carotid artery atherosclerosis. No manic Mondays for us.