A new study, published in The Gerontologist, suggests that caregiving may not take the enormous toll on health that research has previously suggested.
“We’re not saying that family caregiving can’t be stressful, but there’s a notion that it’s so stressful that it causes deteriorating health and increased mortality. This can lead to fear of caregiving and a reluctance to care for loved ones in need,” says first author David Roth, MA, PhD, professor of medicine and director of the Center on Aging and Health at The Johns Hopkins University.
“We’re challenging that narrative as being too exaggerated.”
For decades, research journals and the popular press alike have reported that being a family caregiver takes a significant toll on a person’s health, increasing inflammation and weakening the immune system.
A 1987 study, for example, found that caregivers of people with Alzheimer’s disease had decreased levels of certain immune molecules. Since then, other studies have suggested that family caregivers have increased mortality and rates of psychiatric diseases, decreased immune function and life span, and slower wound healing than other people.
After noticing statistical weaknesses in a handful of recent papers on caregiving and immunity, Roth and team wanted to take a fresh look at the more than three decades of papers on these ideas.
Now, after analyzing 30 papers on the levels of immune and inflammatory molecules in caregivers, the researchers say the association has been overstated and the link is extremely small. Caregiver stress explains less than 1 percent of the variability in immune and inflammation biomarkers, they report.
The analysis focused on studies about immune or inflammatory biomarkers — molecules that can be detected through a blood test. The researchers combed through databases of medical literature to find papers linking the chronic stress of family caregiving and these biomarkers. After reviewing 132 full texts, they narrowed the meta-analysis to 30 original, data-based papers.
In all, the papers spanned from 1987 to 2016 and reported data on 86 biomarkers from 1,848 caregivers and 3,640 noncaregivers. When the researchers began reviewing the manuscripts, Roth says they immediately noticed concerning trends — for one, the studies were quite small.
Of the 30 studies, 16 had fewer than 50 caregivers, with some having as few as 11 or 14. “A lot of these are small exploratory studies that can end up overinterpreting what they find,” Roth says.
In addition, Roth says that the studies tended to compare caregivers found in clinical settings with other adults recruited from senior centers, churches or other community organizations.
“These people differ in many factors besides just who is a caregiver,” Roth says. “Many of the so-called controls are healthy, socially active volunteers.” Due to issues like this, 11 of the papers were given a “moderate” (instead of “low” or “minimal”) ranking for potential bias.
When the team combined the data into a meta-analysis, it found an overall effect size of caregiving on biomarkers of 0.164 standard deviation units. While the effect was statistically significant, the researchers reported that the association was generally weak and of questionable clinical significance. A standard deviation unit of less than 0.20, Roth says, is generally thought to indicate a small effect size.
“It’s not that we didn’t find anything, but it’s a whisper of an effect, not nearly as large as what people have been led to believe,” says Roth.
The researchers hope the new findings help encourage people to be more open to becoming caregivers. The researchers also hope it helps medical professions move away from the idea of caregivers as vulnerable.
“Caregiving, if done right, can actually be an extremely beneficial, healthy activity that enhances your life because you’re engaging in pro-social behavior,” Roth says.
The team is now conducting a large population-based study with carefully matched controls and biomarkers collected at multiple times in order to get even more detailed information on the association — or lack thereof — between caregiving and the immune system.
Source: Johns Hopkins Medicine