Researchers examined data on 2.4 million people aged 60 and older who participated in annual surveys between 2003 and 2017, answering questions about their general health and the number of days they experienced poor physical or mental health. Overall, 41% had household income of no more than $35,000 a year and 10% lacked a high school education.
During the study, the average number of days each month when people aged 60 to 64 experienced poor mental health rose from 2.9 to 3.6. That number climbed from 2.3 to 3.0 days for individuals 65 to 69 and from 2.2 to 2.4 days among those 70 to 74 years old.
Declines in mental health were similar for men and women, but greater for people with lower income and education, researchers report in JAMA Network Open.
Among those with annual household income of $35,000 or less, the average monthly number of poor mental health days rose from 2.9 to 4.1. When the head of the household lacked a high school diploma, the number of poor mental health days increased from 3.6 to 4.4.
"Individuals with lower income and lower levels of education not only lack access to mental health services, but also are on average exposed to more stressful working conditions, lower job security and they have less money to buy health promoting goods," said lead researcher David Rehkopf of Stanford University School of Medicine in California.
"When someone has less resources to meet basic needs, taking care of mental health often is by necessity secondary," Rehkopf said by email. "Research finds that time and time again when basic needs are met, people are able to do more to take care of themselves, which includes their own mental health."
While previous research has documented recent declines in mental and physical health and increases in mortality rates among adults in their prime working years, the trends for older adults and retirees haven't been as clear, Rehkopf and colleagues write.
In the current study, general and physical health improved or were stable for all groups aged 65 and older.
For example, the proportion of people ages 65 to 69 who reported "fair" or "poor" general health dropped from 23% to 19% during the study period. People this age reported an average of 4.9 days of poor physical health in both 2003 and 2017.
Among those 60 to 64 years old, the proportion of people reporting "poor" or "fair" general health held steady at about 23%, while the average number of days with physical health issues climbed slightly from 5.0 to 5.4 a month.
One limitation of the study is that researchers lacked data from health records to verify any diagnosed physical or mental illness. Other drawbacks include the lack of information on any cognitive or memory problems, or on older adults living in nursing homes or other institutional settings.
Even so, "these trends suggest a toxic mix of rising economic uncertainty and poorer access to quality mental health care among elders in the U.S.," said Benjamin Le Cook, director of the Health Equity Research Lab at Cambridge Health Alliance in Massachusetts.
"The greater declines among elders in lower income and education categories are related to worsening stress, anxiety and depression among groups in the U.S. that have faced stagnation in wages before retirement, uncertain benefits and income after retirement, continued obstacles to stable housing, and high medical costs as a percentage of income," Cook, who wasn't involved in the study, said by email.
"Furthermore, access to quality mental health care is only available to less than half of the population with serious mental illness and access is even worse for the elderly, low-income and the uninsured," Cook added.