Newswise — A study just released by Columbia Mailman School of Public Health and Peking University School of Public Health provides some of the first, large-scale evidence that processes of biological aging may contribute to risk of depression and anxiety. Until now nearly all work to date had focused on poor mental health as a risk factor for accelerated aging. A complementary, but less-studied hypothesis is that the reverse process may also occur and accelerated processes of biological aging may, themselves, pose risks to depression/anxiety disorders of older adults. The results are published online in Nature Communications.
The researchers tested associations of blood-chemistry measures of biological aging with prevalent and incident depression and anxiety among a half-million midlife and older adults in the UK Biobank, an ongoing study with 502,536 participants recruited in 2006–2010 at the age of 37–73 years with multiple follow-ups.
The findings showed that adults with more advanced biological age were more likely to experience depression and anxiety at baseline and were at higher risk of depression/anxiety over eight years of follow-up, as compared with peers who were the same chronological age, but who were tested to be biologically younger. At the 8.7 year-follow up mark, participants with older biological age were at a 6 percent increased risk of incident depression and anxiety.
“Among older adults who were free of depression/anxiety at baseline, those whose blood indicated that they were biologically older than their chronological age would predict were more likely to develop depression or anxiety over follow-up compared with those whose blood indicated that they were biologically younger,” said Xu Gao, PhD, assistant professor at Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, China, and first author.
Depression and anxiety are common mental disorders that often co-occur and are associated with increased disability and mortality, especially in older adults. Prevention of depression and anxiety in older adults therefore has potential to mitigate disease burden in an aging population. “This study helps confirm that identifying risk factors and mechanisms of vulnerability to mental disorders must be a public health priority, “observed Gao, who had been affiliated with the Columbia Mailman School Department of Environmental Health Sciences .
The research team had released two earlier papers regarding the connections of air pollution with biological aging (Aging Cell 2022) and with mental health (Environmental Health Perspectives 2023), respectively. “These findings complete the logical circle, demonstrating that air pollution may trigger depression/anxiety by accelerating biological aging,” said Gao.
The researchers analyzed the UK Biobank data for three overlapping groups of participants with whom Gao and corresponding senior author Daniel Belsky, PhD, associate professor of epidemiology at Columbia Mailman School of Public Health, followed up to provide information on their lifestyle and health, and provide biological samples.
The first group included all individuals providing baseline blood chemistry data required for calculation of biological age measurements and who completed mental health surveys at enrollment baseline (N = 424,299). The second group consisted of the subset of the first group who did not have prevalent depression/anxiety at baseline (N = 369,745). The
A recent research conducted by Columbia Mailman School of Public Health and Peking University School of Public Health indicates that biological aging could potentially heighten the likelihood of depression and anxiety, marking some of the first widespread evidence on the subject. Previous studies had predominantly explored the relationship between poor mental health and an increased risk of accelerated aging. However, a comparatively less researched hypothesis suggests that the converse may also be true: hastened biological aging processes may independently pose risks for anxiety and depression in older individuals. The findings have been made available on the internet in the journal Nature Communications.
In the UK Biobank study, which began in 2006-2010 and has had multiple follow-ups, involving over 500,000 adults aged between 37 and 73 years, researchers examined the links between blood-chemistry measures of biological aging and the presence of depression and anxiety. The study also explored whether there was any association between these measures and the development of depression and anxiety over time.
According to the study's results, individuals with a more advanced biological age had a higher probability of experiencing depression and anxiety at the beginning of the study and were at greater risk of developing depression and anxiety over an eight-year follow-up period compared to those of the same chronological age, but with a younger biological age. After 8.7 years of follow-up, participants with a higher biological age had a 6% greater risk of developing depression and anxiety.
Xu Gao, the study's first author and assistant professor at the Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, China, stated that individuals who were initially free of depression and anxiety, but had a higher biological age than what their chronological age would suggest, were more likely to develop depression or anxiety during the follow-up period, compared to those with a lower biological age as indicated by their blood chemistry.
Depression and anxiety are prevalent mental disorders that frequently appear together and are connected with greater disability and mortality, particularly in older individuals. Thus, preventing depression and anxiety in older adults has the potential to alleviate the disease burden in an aging population. Gao, who was previously associated with the Columbia Mailman School Department of Environmental Health Sciences, remarked that this study supports the notion that identifying risk factors and vulnerability mechanisms for mental illnesses must be a public health priority.
The research team had previously published two papers that investigated the associations between air pollution and biological aging (Aging Cell 2022) and mental health (Environmental Health Perspectives 2023), respectively. Gao stated that these latest study results completed the logical circle by showing that air pollution could potentially induce depression and anxiety by hastening biological aging processes.
The research team examined data from the UK Biobank for three groups of participants with overlapping timelines, who were followed up by Gao and corresponding senior author, Daniel Belsky, an associate professor of epidemiology at Columbia Mailman School of Public Health. These participants provided information on their lifestyle and health, and also gave biological samples for analysis.
The first group of participants included all individuals who provided baseline blood chemistry data necessary for calculating biological age measurements and completed mental health surveys at the time of enrollment (N = 424,299). The second group was a subset of the first group, consisting of individuals who did not have depression/anxiety at baseline (N = 369,745). The third group was a subset of individuals from the second group who also participated in the online follow-up mental health survey (N = 124,976), which helped to establish the prospective associations between baseline biological aging and depression.
Individuals who experienced incident depression/anxiety had a higher incidence of chronic conditions over the follow-up period compared to those who did not develop depression/anxiety. For diabetes, the incidence was 6 percent among individuals with incident depression/anxiety versus 3 percent among those without; for cardiovascular diseases, the incidence was 12 percent versus 6 percent, respectively; and for cancers, the incidence was 11 percent versus 8 percent, respectively.
The research team emphasizes that although the findings provide evidence for a prospective association between older biological age and incident depression/anxiety, the study does not explore the specific mechanisms that underlie this link. The relationship between biological aging and mental health could involve multiple stages in the progression of aging processes, which require further research to be fully understood.
Daniel Belsky, the corresponding senior author of the study and an associate professor of epidemiology at Columbia Mailman School of Public Health, explains that while we all age at the same rate in chronological terms, our biological age can vary greatly. Some individuals may age faster than others, experiencing chronic diseases and disability earlier in life and having shorter, less healthy lifespans. Belsky emphasizes the importance of using measurement tools to quantify differences between chronological and biological age, and in this study, the research team used two of these measurement tools to investigate the relationship between aging and mental health.
The results indicate potential avenues for assessing the risk of depression and anxiety in older adults and suggest that therapies that aim to address the biology of aging may play a role in preventing these conditions later in life.
The other co-authors of the study are Tong Geng from Peking University Sixth Hospital and Peking University Institute of Mental Health, Meijie Jiang, Ninghao Huang, and Tao Huang from the School of Public Health at Peking University, China, and Yinan Zheng from the Feinberg School of Medicine at Northwestern University in Chicago.
The study is supported by National Natural Science Foundation of China (82173499); China CDC Key Laboratory of Environment and Population Health, and Canadian Institute for Advanced Research CBD Network.
Columbia University Mailman School of Public Health
Founded in 1922, the Columbia University Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Columbia Mailman School is the fourth largest recipient of NIH grants among schools of public health. Its nearly 300 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change and health, and public health preparedness. It is a leader in public health education with more than 1,300 graduate students from 55 nations pursuing a variety of master’s and doctoral degree programs. The Columbia Mailman School is also home to numerous world-renowned research centers, including ICAP and the Center for Infection and Immunity. For more information, please visit www.publichealth.columbia.edu
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