For lead author Sarah Woods, assistant professor of family and community medicine at UT Southwestern Medical Center, the results were surprising.
She and her colleagues had expected to find health impacts from both family and intimate dysfunction. One reason they may not, she said, is due to the changing nature of marriage, especially the role of divorce.
"Adults are waiting longer to marry, if they marry at all ," Woods said. "And they may be less likely to be married to that same person for the rest of their lifespan. But you have your family for all of your life."
In fact, Woods said, the majority of the people in the study had living parents or siblings. If the dynamics of the interactions are negative, then family-based stress could continue to impact a person as they age.
"Family relationships are long and emotionally intense," Woods said. "These are people you are connected to forever. If you are sensitive to emotional stress, then being bathed in that stress would over time wear and tear on your body."
While intimate partner relationships weren't found to have as much of an impact on a person's health, they are likely to reflect the suffering happening in other areas, Thomas pointed out.
"The strain in intimate partner relationships was related to greater strain in family relationships, which speaks to how intimate relationships are embedded in and affect one's other social relationships, " Thomas said.
While more research is needed to tease out the dynamics of the interactions, the study's results should be a wakeup call for dysfuntional families and health care practitioners, Woods said.
"It's our takeaway that if your family or relationship are conflictual or unhealthy in adulthood, it could be very important to work to improve them, perhaps by therapy," Woods said. "Until now that's not something we would typically consider for somebody in the middle of their life."