Trust in US institutions, particularly the government, has plunged in President Donald Trump's first year in office, according to a survey released on the eve of the World Economic Forum in Davos.

The annual Edelman Trust Barometer measures overall trust in the four institutions - the government, media, business and non-governmental organisations.

Trust among these institutions fell more steeply in the US than in any of the 28 countries surveyed, the barometer showed.

Mr Trump has broken with presidential tradition and repeatedly denounced the media and judiciary - attacks his critics say risk undermining public confidence in those institutions.

By contrast, the country that saw the biggest trust gains among its own citizens was China, after a year in which President Xi Jinping cemented his hold on power at a triumphal party congress.

Faith in the Chinese government jumped eight points to 84%. In the United States, it fell 14 points to 33%.

"The US is enduring an unprecedented crisis of trust," said Richard Edelman, head of the communications marketing firm that commissioned the research.

Mr Xi was the headliner in Davos last year, days before Mr Trump was inaugurated. This year, Mr Trump is the main attraction.

He is expected to defend his "America First" policies in a speech on the final day of the conference of policymakers, CEOs, bankers and celebrities in the Swiss Alps, which runs from 23-26 January.

It showed a revival of faith in "experts", including academics and businessmen.

Pointing to the steep erosion in trust in the US, Mr Edelman said it was the first time since the survey began 18 years ago that such a precipitous drop was not linked to a specific event, such as an economic crisis or catastrophe, such as the 2011 Fukushima nuclear disaster in Japan. 

Instead, it comes at a time when the US economy is showing robust growth and stock markets are at record highs.

"Normally when things are going well, trust is pretty good," Mr Edelman said. "Increasingly there is a disconnect between trust and economic outcomes."

He attributed this to a politicisation of the public discourse in the US and elsewhere that has left many people confused about what is fact and what is fiction.

The survey showed nearly two in three people are unable to distinguish reliable news from rumours and falsehoods.

While trust in journalism rose to its highest level in years, faith in search engines and social media platforms such as Google, Twitter and Facebook fell in 21 of the 28 countries, making media the least trusted of the four institutions globally.

The Edelman survey is based on the opinions of more than 33,000 people and conducted between 28 October and 20 November of last year.

It showed an even deeper lack of trust in US institutions among the "informed public" - people who are college educated, earn above-average incomes and consume news regularly.

Among this group, trust declined a substantial 23 points, putting the US in last place among the 28 countries surveyed, below Russia and South Africa. In 2017, it ranked sixth.

In the broader US population, faith in the government was equally low among respondents who said they voted for Mr Trump and those who supported his Democratic rival Hillary Clinton in the 2016 election.

But trust in the media was significantly higher among Mrs Clinton's backers.

The survey also showed that Americans' trust in their own companies fell more steeply than in any other country, with Switzerland and Canada registering the highest levels of trust in their homegrown brands.

It showed a revival of faith in "experts", including academics and businessmen.