Carol Musil of the Case Western Reserve University Frances Payne Bolton School of Nursing tracked and focused on the health and well being of 240 grandmothers for six-and-a-half years to see how the responsibilities of caring for grandchildren 16 years old and younger affected the grandmothers' health.
Study subjects were surveyed about their physical and mental health annually for the first three years, and two more times about two years apart at the end of study.
The grandmothers -- average age 57.5 at the beginning of the study -- were in three caregiving situations: those who are full-time caregivers for their grandchildren, living in multigenerational homes or non-caregivers.
They were randomly selected throughout Ohio, from rural, suburban and urban backgrounds.
"Although we expected the primary caregiver grandmothers raising grandchildren would have more strain and depressive symptoms, we were surprised at how persistent these were over the years examined in the study," Musil said in a statement.
Despite signs of depression and family stress, researchers found grandmothers, especially those raising grandchildren, were generally open to receiving various forms of help. That implies, Musil said, grandmothers might be open to resourcefulness training, which has helped to reduce depressive symptoms in grandmothers in pilot studies, Musil said.
Notable deaths of 2014 [PHOTOS]