PHOENIX, Ariz. -- May 13, 2021 -- In the largest study of the associations between smoking and cardiovascular disease on cognitive function, researchers at the Translational Genomics Research Institute (TGen), an affiliate of City of Hope, found both impair the ability to learn and memorize; and that the effects of smoking are more pronounced among females, while males are more impaired by cardiovascular disease.
The results appear today in the journal Scientific Reports.
Previous attempts to quantify cognitive function among smokers and assess sex differences produced mixed results. The TGen researchers attribute this to the limited size of previous data sets. By analyzing data representing more than 70,000 individuals worldwide -- generated through TGen's online cognitive test called MindCrowd -- the current study produced results that indicate definitive trends.
"These results suggest that smoking and cardiovascular disease impact verbal learning and memory throughout adulthood, starting as early as age 18," said Matt Huentelman, Ph.D., TGen Professor of Neurogenomics, a MindCrowd founder, and the study's senior author. "Smoking is associated with decreased learning and memory function in women, while cardiovascular is associated with decreased learning and memory function in men."
Besides Alzheimer's disease, the most significant cause of cognitive decline is known as "vascular contributions to cognitive impairment and dementia" or VCID, which arises from stroke and other vascular brain injuries that cause significant changes to memory, thinking and behavior: smoking and cardiovascular disease exacerbate VCID.
"The reasons for these sex-modification effects are not entirely understood," said Candace Lewis, Ph.D., a Postdoctoral Fellow in Dr. Huentelman's Lab, and the study's lead author. "Our findings highlight the importance of considering biological sex in studying vascular contributions to cognitive impairment and dementia."
This study's findings are important, Dr. Lewis said, since cigarette smoking is the nation's leading cause of preventable disease and death, accounting for nearly 1 in 5 deaths, and cardiovascular disease is the leading cause of disease and death worldwide, and is an important predictor of cognitive decline and VCID. Vascular diseases also are associated with increased risk of Alzheimer's, which is the nation's 6th leading cause of death.
Because the study included a wide range of adults, 18-85, it allowed researchers to assess the relationship between smoking, cardiovascular disease, and verbal memory in the broadest single study age range used to date.
The researchers noted that few studies have previously assessed the effects of cardiovascular disease in younger adults, and that understanding the relationship between cardiovascular disease and cognitive function in young adults may be necessary for understanding possible treatment and intervention opportunities.
"This study points out some unpredicted but important differences between the sexes relating to cognitive decline," said Brian Tiep, M.D., City of Hope director of pulmonary rehabilitation and smoking cessation. "The impact on mental acuity seems progressive over time -- some more rapid than others. Living habits related to diet, exercise and smoking certainly are consequential and may differ between men and women. People undergoing cancer care may be cognitively effected by the cancer and its treatment."
"This study supports the importance of maintaining cardiovascular health and quitting smoking not only in support of their cancer care but to improve brain function," Dr. Tiep added.
Also contributing to this study were: the Arizona Alzheimer's Consortium, the Norwegian University of Science and Technology, the Evelyn F. McKnight Brain Institute at the University of Miami, the Miami Clinical and Translational Science Institute, and the University of Arizona.
The study -- Smoking is associated with impaired verbal learning and memory performance in women more than men -- received support from: the Mueller Family Charitable Trust, the Arizona Department of Health Services through the Arizona Alzheimer's Consortium, Flinn Foundation, The McKnight Brain Research Foundation, and a grant from the National Institute on Aging. The TGen Foundation led philanthropic efforts to support MindCrowd.
MindCrowd is an internet-based study of how the human brain changes with age. Over 225,000 participants have joined the study since its inception in 2013. It is open to all individuals who are 18 years of age and older and the site is available in both English and Spanish.
About TGen, an affiliate of City of Hope
Translational Genomics Research Institute (TGen) is a Phoenix, Arizona-based nonprofit organization dedicated to conducting groundbreaking research with life-changing results. TGen is affiliated with City of Hope, a world-renowned independent research and treatment center for cancer, diabetes and other life-threatening diseases: cityofhope.org This precision medicine affiliation enables both institutes to complement each other in research and patient care, with City of Hope providing a significant clinical setting to advance scientific discoveries made by TGen. TGen is focused on helping patients with neurological disorders, cancer, diabetes and infectious diseases through cutting-edge translational research (the process of rapidly moving research toward patient benefit). TGen physicians and scientists work to unravel the genetic components of both common and complex rare diseases in adults and children. Working with collaborators in the scientific and medical communities worldwide, TGen makes a substantial contribution to help our patients through efficiency and effectiveness of the translational process. For more information, visit: tgen.org. Follow TGen on Facebook, LinkedIn and Twitter @TGen.
TGen Senior Science Writer