Global health researchers at Duke Kunshan University have published the first study to examine the link between alcohol-induced “Asian flush” and cognitive impairment among the eldest members of the Chinese population.
Appearing in Frontiers in Aging Neuroscience, an international geriatrics journal, the paper looked at the association between four variants of the aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) genes and cognitive impairment in China’s “oldest-old” category.
Researchers found that some genetic variations, known as single nucleotide polymorphisms (SNPs), related to alcohol metabolism were associated with increased odds of experiencing cognitive impairment.
The study, authored by a faculty-student partnership at DKU’s Global Health Research Center, may help the elderly reduce their risk of cognitive impairment through health interventions, by observing the gene mutation, ALDH2, which causes Asian flush.
“Many genes are not easily observable. People cannot identify whether they carry certain genes by visual observation, and they have to undertake a test to find out,” said assistant professor of global health Dr. Chenkai Wu, who led the study.
“But people who carry the ALDH2 gene variant do not need testing. They will know if they are carriers by seeing whether they have facial flushing after taking alcohol. We hope the research findings will lead to improved health management and targeted prevention of cognitive impairment.”
Data was gathered from the Chinese Longitudinal Healthy Longevity Survey genetic sub-study, which had 1,949 participants aged over 90. No previous study has examined the association between alcohol metabolism-related genes and cognitive impairment among China’s oldest-old.
Recent literature suggested the ALDH2 mutation is associated with alcohol metabolism, and that ethanol intake might jointly increase the risk of Alzheimer’s disease in mice. Previous studies indicated that the presence of the ALDH2 mutation resulted in several side effects from alcohol consumption, including facial flushing, dizziness and increased heart rate. However, it is unclear whether this synergistic effect exists among humans. The Duke Kunshan University global health team expanded the animal model to human subjects.
Innovation and breakthrough: the first such study focusing on the Chinese oldest-old
Studies on Alzheimer’s disease and senile cognitive impairment have mostly focused on Asian populations. The DKU study was the first conducted among a sample of the very eldest members of society.
“We focused on the Chinese oldest-old because the risk of cognitive impairment increases with age,” said Dr. Wu.
The findings suggested that carrying the ALDH2 gene was one of the causes for developing cognitive impairment. The authors noted there were various causes of cognitive disorders, such as genetic, natural and social environmental factors, as well as personal health habits. However, the easily observable quality of the ALDH2 gene provides those with Asian flush the opportunity to make informed decisions about managing their health.
With the dominant model, the team conducted observations and data analysis on the participants in a multivariate adjusted logistic model. The results indicated that carrying the ALDH2 and ADH mutation was associated with higher odds of cognitive impairment among the oldest-old population.
Tingxi Long, from the inaugural class of DKU’s undergraduate program, says there is great access to research opportunities at the university
Tingxi Long, a member of Duke Kunshan’s inaugural class of undergraduates who majors in global health, participated in the data analysis and paper writing as co-first author of the study. Previously, under the guidance of Dr. Wu, Long published a paper exploring the declining diet quality in older U.S. population as the first author in the JAMA Network Open. Long, who will graduate in May, plans to join Johns Hopkins University in August to study biostatistics.
“I have come across many challenges during the study. It took about a year from paper submission to acceptance to publication, after rejection by several journals,” said Long. “I started to doubt myself. But hard work pays off. To overcome the difficulties, we learn and work harder, and finally welcomed a good result.”
Tingxi Long, then a freshman, participated in the research project using a community empowerment-based approach for health management among chronic disease patients, led by global health professor Lijing Yan
Long said the study could not have been completed without the cooperation and support of the global health team. “I didn’t have any research experience before this project,” said Long. “But our research team have given me so much help. Dr. Wu provided great guidance and graduate students in global health taught me how to use statistical software. The team analyzed the results and wrote the paper together. It is really a great privilege to be a part of the global health team. I have not only expanded academic skills, but built a more positive mindset towards research.”
According to Dr. Wu, Duke Kunshan University provides undergraduates with great research opportunities, enabling them to participate in projects and expand their academic horizons during their first or second year.
“It takes time from joining a research project to seeing the findings published. So, the research process helps students build not only academic skills but also a resilient mindset,” said Dr. Wu. “Duke Kunshan University has outstanding research strength and teamwork, allowing students access to research projects during their freshman or sophomore years. Tingxi Long is an excellent student who has outstanding academic ability and soft skills. She works hard in study and research. I wish her best of luck and great success in the field she loves.”
A health warning for those with Asian flush
China’s population has been aging at an increasing rate. Data from the seventh National Census in 2020 showed the number of people aged 60 and above had reached 264 million, accounting for about 18.70% of the total population, of which 190.64 million people were aged 65 and above, or 13.50%. Compared with 2010, the population aged 60 years and above has increased by 5.44%.
The World Health Organization (WHO) estimates that there are about 50 million people with cognitive impairment worldwide, with 10 million new cases each year. As the world’s most populous country, China has the largest number of people with cognitive impairment. The 2020 data on Alzheimer’s patients released by Chian’s National Health Commission indicated the country had about 10 million patients suffering from the disease, the highest number of any country in the world. The number of Alzheimer’s patients in China will exceed 40 million by 2050. According to the Chinese Geriatrics Society, there will be 22 million senile dementia patients in the elderly aged 60 and above in China, which is expected to reach 28.98 million in 2050.
Dr. Chenkai Wu’s research team
There are many causes of cognitive impairment, and mild cognitive impairment may develop into Alzheimer’s disease. Early detection of incidence, causes and risk factors of mild cognitive impairment will help to support targeted prevention and treatment, which is the key to preventing Alzheimer’s disease.
Looking ahead, the global health research team plans to break through boundaries in this field and explore the interaction of various causes for cognitive impairment, providing more scientific evidence for disease prevention and health management.
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