Four in 10 people have deleted a social media account in the past year due to privacy worries, study says

There is a serious lack of trust in social media such as Facebook and Twitter and consumers expect brands that advertise on such platforms to urgently find solutions, according to research published Monday.

Privacy concerns and the circulation of fake news are contributing to people's distrust of content on social platforms, said the study by public relations consultancy Edelman, with 70 percent of respondents expecting businesses and advertisers to put pressure on social media sites to address false information and remove offensive content.

Context was also seen as important by people surveyed, with 48 percent saying it's a brand's fault if its advertising appears next to hate speech or violent content.

"We learned that there is a serious lack of confidence in social media in all regions of the world. This is a cry from the heart; people are scared. They are outraged about the violation of their privacy, and uncertain about the truth because of the plague of fake news," said the consultancy's president and CEO Richard Edelman in a statement emailed to CNBC.

The Cambridge Analytica data leak and Russian-produced fake news that undermined the 2016 U.S. Presidential Election have contributed to people's concerns. In April, Facebook said that it would remove 270 pages and accounts by the Internet Research Agency, the Russian organization that attempted to influence the U.S. Presidential Election. Last month, Facebook and Twitter both announced stricter political ad guidelines ahead of the U.S. midterm elections.

Forty percent of those surveyed had deleted at least one social media account in the past year because of privacy concerns and 62 percent wanted more regulation of such platforms.

Edelman surveyed 9,000 people in Brazil, Canada, China, France, Germany, India, the United Arab Emirates, U.K. and U.S. for the study that was published as part of the Cannes Lions International Festival of Creativity in France.

Richard Edelman urged companies to be honest about how they use social media, such as for advertising, saying that people want clear identification when something is sponsored, as well as when their data is being collected. Consumer goods conglomerate Unilever also announced Monday that it would no longer work with "influencers" on social media who have fake followers in an attempt to help rebuild trust in digital marketing.

People also expect businesses to take on big issues such as racism and sustainability. "Consumers believe brands can do more to solve them than government can," Richard Edelman said.

The social media study builds on Edelman's annual trust barometer revealed at the World Economic Forum in Davos in January, which suggested that 41 percent of people globally trust social media, with drops in most western countries on 2017.