Smart toilet checks urine for medical problems
December 3, 2019
A smart toilet has the potential to outperform wearables in monitoring and improving health, according to metabolism scientists at the University of Wisconsin–Madison and the Morgridge Institute for Research, who are working to put the metabolic health information contained in urine to work for personalised medicine.
Urine contains a virtual liquid history of an individual’s nutritional habits, exercise, medication use, sleep patterns and other lifestyle choices. It also contains metabolic links to more than 600 human conditions, including some of the major killers such as cancer, diabetes and kidney disease.
The team has two essential questions. First, can frequent monitoring and testing of urine samples glean useful real-time information about an individual’s health? And, secondly, can a technology platform be adapted to toilets that can make the collection process simple, accurate and affordable?
They received some promising answers to the first question in a small pilot study conducted this year, the results of which were published in Nature journal NPJ Digital Medicine. Two research subjects consistently collected all urine samples for ten days and submitted those samples for tests with both gas chromatography and mass spectrometry for a complete readout of their metabolic signatures.
The two subjects also happen to be lead authors on the paper: the Morgridge Institute’s Joshua Coon and Ian Miller, data scientist with the Coon research group. Collectively, they provided 110 samples over the ten days, and also used wearable technology to track their heart rates, number of daily steps, calorie consumption and sleep patterns.
They found that the samples do indeed contain a health fingerprint that follows the ebbs and flows of daily life. For example, the subjects kept records of coffee and alcohol consumption, and the biomarkers with a known connection to both of those drinks were abundantly measured. One subject took acetaminophen, which was measured in urine by a spike in ion intensity. They were also able to measure with precision the metabolic outputs from exercise and sleep.
For the next step, the research team is designing a smart toilet that will incorporate a portable mass spectrometer that can recognise the individual and process samples across a variety of subjects. They plan to install the toilet in their research building and expand the user group to a dozen or more subjects. Coon said the design was “a bit Rube Goldberg-like” but functional.
“We know in the lab we can make these measurements,” said Coon, a UW–Madison professor of chemistry and biomolecular chemistry. “And we’re pretty sure we can design a toilet that could sample urine. I think the real challenge is we’re going to have to invest in the engineering to make this instrument simple enough and cheap enough. That’s where this will either go far or not happen at all.”
While the pilot experiment didn’t examine health questions, the researchers say many possibilities exist. For example, testing could show how an individual metabolises certain types of prescription drugs in ways that could be healthy or dangerous. Also, as the population ages and pursues more stay-at-home care, urine tests would indicate whether people are taking their medications properly and if those medications are having their intended effects.
Coon also believes the smart toilet concept could have major population health implications, not unlike the National Institutes of Health’s All of Us human genome database.
“If you had tens of thousands of users and you could correlate those data with health and lifestyle, you could then start to have real diagnostic capabilities,” he said, adding that it might provide early warning of viral or bacterial outbreaks.
Coon, who runs the National Center for Quantitative Biology of Complex Systems, said the idea of meta-scale urine testing had intrigued him for some time.
“Josh mentioned this at a group meeting one time and it was met with laughter,” Miller recalls. “I thought, you know, I kind of like the idea. I already track a lot this stuff in my everyday life.”
Coon added: “So we went out and bought a couple coolers and started collecting.”
While the mass spectrometer small molecule analyses are being done on $300,000 machines, Coon said portable mass spectrometer technologies existed at a tenth of that cost. He said that with a market this massive, they could eventually hit a reasonable cost threshold.
“Almost every automobile on the road is more complicated than that portable mass spectrometer,” he said.