Can Twitter predict heart disease risk?

Commonly known risk factors for heart disease include smoking, a sedentary lifestyle and poor diet. However, psychological well-being plays a huge part as well – and Twitter is a possible indicator of this, according to new research from the University of Pennsylvania and the University of Melbourne.

The researchers used “emotional dictionaries‟ to analyse public tweets that were made between 2009-2010; this included tweets and health data from 1,300 U.S. counties that are home to 88 percent of the US population. 

The findings revealed that negative emotions such as anger, stress and fatigue in tweets from any given community – using expletives or words like "hate‟ – translated into a higher heart disease risk for that community. This trend persisted even after variables such as income, lifestyle and education were taken into account. 

On the flipside, positive emotional language – using words like "wonderful" or "friends" – may serve to reduce the number of heart disease cases. 

This suggests that using Twitter as a window into a community’s collective mental state may provide a useful tool in epidemiology, according to the press release. 

"Psychological states have long been thought to have an effect on coronary heart disease," said co-author Margaret Kern, Science Daily reported. 

"For example, hostility and depression have been linked with heart disease at the individual level through biological effects. But negative emotions can also trigger behavioural and social responses; you are also more likely to drink, eat poorly and be isolated from other people, which can indirectly lead to heart disease," Kern said.

The team claims that Twitter can capture more information about coronary heart disease risk than many known traditional factors combined, by analysing the psychological state of an entire community. Previous research has shown that the combined characteristics of communities can be more predictive of physical health than the reports of any one individual. 

Study co-author H. Andrew Schwartz notes that negative tweeters may not be the ones who suffer directly from heart disease – those tweets can have indirect effects, too. 

"The relationship between language and mortality is particularly surprising, since the people tweeting angry words and topics are in general not the ones dying of heart disease," said co-author H. Andrew Schwartz, Science Daily reported. "But that means if many of your neighbours are angry, you are more likely to die of heart disease."

This article first appeared in the February/March 2015 issue of Global Health and Travel.