A recent study that I published with a colleague, Kate Bennett, from the University of Liverpool, U.K., in the journal Brain Behavior, Immunity, and Health, has revealed that the chronic stress of caring can have a damaging effect on the future health of caregivers. Caregivers, who were initially healthy at study entry, had a 33 percent greater risk of illness or disability just eight years later.
This is a good example of how chronic stress can get inside the body, where it influences our immune, cardiovascular, and hormonal systems to impact our future health.
What is the Link Between Caregiving and Chronic Stress?
When researchers want to examine the impact of chronic stress (i.e., stress that endures over prolonged periods of time) on our health, for ethical and practical reasons we cannot expose people to such health-damaging experiences. Researchers, particularly in the field of health psychology, tend to find proxy exemplars whose chronic stress is likely to happen naturally in our environments. Family caregiving is one such example. Subjects care for sick or disabled family relatives or friends, often under difficult circumstances (e.g., long hours, severe illnesses) for extended periods of time, sometimes many years. Thus, by looking at the effect of caregiving on health, we find one of the best models for examining the impact of chronic stress on health.
What is important about this study?
While there are many studies showing that caregiving can be damaging to health biologically, and physically, there are often methodological weaknesses that hinder our ability to infer causation, i.e., does caregiving cause future illness risk and disability? Some of these cases do not control for factors such as existing illness and disability, some recruit family carers from support groups so they seem to be highly stressed and likely to be health-compromised already, with few studies recruiting healthy and unbiased samples from the general population at large.
Thus, this particular study recruited from a large, population-based dataset, the Understanding Society in the U.K., where we selected individuals who reported that they were caring for others inside or outside the home, reported the number of hours of caring, and compared them to age and gender-matched controls who were not caring. We then included only all those who were initially healthy in 2011, (reported no illnesses or disability, were not on medications) and we examined whether these caregivers and controls differed on allostatic load, a cumulative index of cardiovascular, metabolic, and hormonal dysregulation at that time. We examined if caregivers reported more illnesses and disability (e.g., angina, asthma, arthritis, cancer, heart disease, and hypertension) eight years later. Therefore, while the study is still observational, it is stronger and provides more robust evidence for causation.
Why measure allostatic load?
When people experience chronic stress they are more likely to have dysregulation of not just one biological health system, but of several others, all of which interact with each other. These include increased levels of inflammatory cytokines which are part of our immune system functioning, increased blood pressure from our cardiovascular system, and hormones from the metabolic system. Together, they control, regulate and maintain normal bodily functions. Thus, when all three systems are dysregulated simultaneously it causes a biological “wear and tear” effect on our bodies known as allostatic load. Higher levels of allostatic load are associated with an increased risk of future morbidity and mortality.
Our findings showed that the chronic stress of caring is biologically damaging, with increased levels of allostatic load in family caregivers compared to non-caregivers and when we examined the health impact over time we found a greater risk of illness and disability in family caregivers eight years later.
What are the implications of the research?
The authors found that in the previously disease-free groups, 24 percent of carers compared to 16.5 percent of non-carers reported having a chronic health condition, such as heart disease, diabetes, or asthma at follow-up in 2019.
If we take the U.K. as an example, where there are approximately 7 million family caregivers, this would mean that there are 7.5 percent more caregivers who now have an illness or disability compared to the general population. This equates to almost 525,000 family caregivers who have been negatively affected by the stress of caregiving. Moreover, allostatic load was associated with this excess risk, and, more interestingly, when we checked to see if it mattered for future health risk if someone continued caring or stopped caring in 2011, it didn’t matter! This then implies that there seems to be a health scarring effect of caring that goes beyond its cessation.
Our results also suggest the importance and relevance of supporting family carers early on, as they deal with the stresses and strains of caring. This is particularly important, as the economic costs associated with family caring run into billions annually. If family carers get ill themselves and are unable to care for their loved ones, that will cost the exchequer, as institutionalisation is more likely.