That gross, waxy stuff in your ears could actually say a lot about your health.

Researchers in China have identified key differences in the makeup of earwax in people with Parkinson’s disease compared to people without the condition, suggesting the sticky stuff holds secrets that could flag a person’s risk of eventually developing the condition.

Scientists at Zhejiang University took earwax samples from 100 people with Parkinson’s and 79 without. They chose earwax because much of it is made up of sebum, an oily substance that undergoes chemical changes in cases of Parkinson’s, and releases distinct volatile organic compounds (VOCs).

Parkinson’s triggers neurodegeneration, inflammation, and oxidative stress, altering sebum’s composition and creating a distinct odor. 

It also progressively damages the brain, causing tremors, stiffness, and slow movement. Over time, symptoms worsen to include sudden freezing, speech loss, swallowing problems — often leading to pneumonia — and falls, both common causes of death among people with Parkinson’s.

Four specific types of VOCs stood out among people with the condition, suggesting that earwax could potentially be an accessible indicator of Parkinson’s, which would allow patients to avoid invasive diagnostic tests and spinal taps.

Around 1million Americans and 10million people globally currently have the disease, with nearly 90,000 new cases diagnosed each year. As that number is projected to climb, early diagnosis is more important than ever. While there is no cure, medication regimens can be started early to treat symptoms and slow down the progression of the disease. 

Researchers in China have identified key differences in the makeup of earwax in people with Parkinson’s disease (PD) compared to people without the condition, suggesting the sticky stuff holds secrets that could flag a person’s risk

Researchers fed the VOC data from the samples of earwax into an algorithm that categorized subjects’ Parkinson’s status accurately 94 percent of the time, demonstrating the potential for a fast, reliable diagnostic tool.

The VOCs that stood out to researchers were all significant in differentiating between people with the condition and those without it, even after accounting for age and lifestyle factors.

Two of the VOCS, Ethylbenzene & 4-Ethyltoluene, are compounds commonly found in plastics and petroleum products. 

Their presence suggests inflammation in the brain, which is a key driver of the breakdown of dopamine in the brain. 

Dopamine, while often thought of as a ‘feel good’ neurotransmitter, is a key chemical messenger that regulates movement control. 

As dopamine levels plummet while Parkinson’s progresses, people become steadily more immobile. 

Another significant VOC was Pentanal, which is produced when fats break down. 

Elevated levels suggest cell damage, a hallmark of Parkinson’s. The compound has been linked to an accumulation of protein clumps in patients’ brains.

Parkinson’s disease progressively damages the brain, causing tremors, stiffness, and slow movement. Over time, symptoms worsen to include sudden freezing, dangerous falls, speech loss, and swallowing problems

And the VOC 2-Pentadecyl-1,3-dioxolane likely reflects issues with the metabolism of fats, which could have originated from microbiome changes in the skin of patients.

It’s unclear whether this VOC has any direct links to PD, but there is an expanding body of research pointing to a connection between PD and an imbalance in the gut microbiome. 

Research suggests that VOCs are produced by the balance of good bacteria in the gut, which have also been associated with brain health.

An imbalance that allows harmful bacteria to flourish, leading to a proliferation of toxins that can cause inflammation in the brain.

VOCs come from a wide array of toxic sources in the environment, from pesticides used to grow food, industrial chemicals in gasoline, and solvents in everyday items like dry cleaning chemicals and adhesives, to cleaning products, car emissions, and contaminated groundwater. 

Parkinson’s is believed to be caused by a confluence of genetic and environmental factors. 

It is the world’s fastest-growing brain disorder, and, according to NIH research, ‘exposure to environmental toxicants is the principal reason.’  

In the US, deaths from Parkinson’s disease have more than doubled in the past 20 years, with about 35,000 deaths in 2019 compared to 14,500 in 1999. 

Parkinson’s death rates rose from 42 to 65 deaths per 100,000 from 1999–2017

While considering the clues that earwax can provide about Parkinson’s development is new, investigating the role that VOCs play is not.

A sweeping 2023 meta-analysis identified distinct VOCs present in the breath and skin oil in people with the disease compared to those without it.

These compounds are specifically linked with oxidative stress, or a barrage of damage that cells endure before dying.

Dr Hao Dong, a co-researcher on the recent study, said: ‘This method is a small-scale single-center experiment in China.

‘The next step is to conduct further research at different stages of the disease, in multiple research centers and among multiple ethnic groups, in order to determine whether this method has greater practical application value.’