Understanding health food messages on Twitter for health literacy promotion.

AIMS: With the popularity of social media, Twitter has become an important tool to promote health literacy. However, many health-related messages on Twitter are dead-ended and cannot reach many people. This is unhelpful for health literacy promotion. This article aims to examine the features of online health food messages that people like to retweet.

METHODS: We adopted rumour theory as our theoretical foundation and extracted seven characteristics (i.e. emotional valence, attractiveness, sender's authoritativeness, external evidence, argument length, hashtags, and direct messages). A total of 10,025 health-related messages on Twitter were collected, and 1496 messages were randomly selected for further analysis. Each message was treated as one unit and then coded. All the hypotheses were tested with logistic regression.

RESULTS: Emotional valence, attractiveness, sender's authoritativeness, argument length, and direct messages in a Twitter message had positive effects on people's retweet behaviour. The effect of external evidence was negative. Hashtags had no significant effect after consideration of other variables.

CONCLUSION: Online health food messages containing positive emotions, including pictures, containing direct messages, having an authoritative sender, having longer arguments, or not containing external URLs are more likely to be retweeted. However, a message only containing positive or negative emotions or including direct messages without any support information will not be retweeted.