Using Google Trends for health research

A glance at trending Google searches reveals that the world isn’t all that concerned about health. As an internet community we’re much more interested in Johnny Depp, the NBA draft and Snapchat’s new map feature. But what happens when we do, on occasion, enter a health-related search term in the world’s favorite search engine? That data can reveal interesting health trends discoverable by researchers or anyone nerdy enough to go searching.

Google Trends is a free service that shows how often a particular keyword, subject or phrase is entered relative to the total search volume across a region. Basically, Google makes certain analytics public so you can check the popularity of a topic on the internet.

The only health-related topic to make a splash last week was “Senate healthcare bill,” which was the 11th most popular search term on Thursday with 100,000+ searches. As Google’s Health Care in the US page explains, “As health care changes are being discussed by lawmakers, people are turning to Google to understand what is to come.”

For anyone interested in what the internet is asking, Google Trends is a pretty cool tool. You can see the popularity of a topic over time, view the top trending questions on healthcare or visualize search interest by region.

But Google Trends is more than just a fun tool for people with too much time on their hands. For several years now, scientists and academics have been exploring the possibility of using Google searches for health research.

A review of the research explains how internet searches might provide insight into population behavior and health-related phenomenon. While there are lots of questions about methodology, Google Trends has already been used to study infectious disease, mental health and substance abuse, other non-communicable diseases and general population behavior.

The most ambitious studies attempt to define a causal relationship between Google trends data and a health-related outcome. For example, one study used search queries to explore the link between Brazilian President Lula da Silva’s laryngeal cancer diagnosis announcement and population interest in primary cancer prevention. Researchers found that there were 1.1 million excess cessation queries the month after Lula’s announcement, suggesting that celebrity diagnosis may promote primary cancer prevention.

Other research is descriptive, meaning it attempts to analyze internet searches to describe temporal or geographic health-related trends. While some of these surveillance projects have notoriously failed (Google Flu Trends just kept missing the mark), others show that search engine data can offer powerful insights. For example, researchers found that gastroenteritis-related search terms correlated strongly with existing norovirus diseases surveillance data in the US. Internet queries may facilitate rapid identification of norovirus season onset, elevated peak activity and potential emergence of novel strains.

Whether you’re a research scientists or just curious on your coffee break, Google Trends offers insights about health and population behavior. But while many studies have been successful, experts like Stephen Mooney - a Columbia University epidemiologist who studies big data and public health - remain cautiously optimist. Reflecting on a 2016 study that used internet queries to improve early detection of pancreatic cancer, Mooney believes “The potential benefit is huge, but it would be easy to naively assume we know more about this than we do.”