11 million working days are lost in the UK every year because of stomach upsets, or cases of infectious intestinal disease (IID), some of which are linked to food but not all, according to a new report published recently by the Food Standards Agency (FSA) conducted by a group of organizations and led by The University of Manchester.

The study is the biggest of its kind to be conducted in over 10 years and looked at the impact of IID, which typically is vomiting or diarrhoea, on people in the UK.

The study recruited individuals from general practices throughout the UK and asked them to fill in symptom questionnaires, attend interviews and undergo clinical tests. Official national statistics were also used to help estimate the true incidence of IID in the UK.

Using data covering the period 2008-09, it found that:

  • About 17 million people, about 1 in four of the population of the UK, have IID every year.

  • About half of them take time off work or school: for workers the FSA estimates this represents about 11 million lost working days.

  • Abut 2% of the population visits their GP with symptoms of IID every year; an estimated 1 million consultations a year.

  • For every IID casereported to national surveillance, there are about 10 GP visits and 147 cases in the community.

  • Based on stool sample tests of people with IID, the most commonly identified microorganisms were norovirus, sapovirus, Campylobacter spp. and rotavirus.

  • Only 1 sample tested positive for Clostridium difficile (less than 1% of cases), implying this bacterium is not as common in the community as in hospital settings.

Although many norovirus infections are spread by person to person contact, it has the potential to become a foodborne illness and the FSA includes it in its 2010-2015 Foodborne Disease Strategy.

Campylobacter is found on raw poultry and the finding that it is a main cause of bacterial IID in the UK underlines the need to reduce this source of infection which causes about half a million cases of illness in the UK every year. A recent survey by the FSA found that two thirds of chickens on sale in the UK that they sampled were contaminated with the bacterium.

The report also compared the data from 2008-09 with the situation in England in the mid 1990s:

  • The incidence of community-based IID was 43% higher in 2008-09 than during 1993-96, but the number of people who saw their GP about IID was 50% lower.

  • Reporting IID cases to national surveillance has improved since the mid 90s, for those who visited their GP. This suggests GPSs are more likely to take a stool sample, and/or recording of IID episodes for those using primary healthcare services has improved.

  • But, since fewer people are going to GP when they have IID, more cases in the community are unrecognized and unreported.

  • About 2% of people with IID contacted NHS Direct: this number was not high enough to explain the big drop in GP consultations.

The lead researcher of the study was Professor Sarah O’Brien, who was then with The University of Manchester and is now at the University of Liverpool. She told the press that:

“It’s easy to dismiss diarrhoea and vomiting as a trivial illness, but this study reinforces just how many people’s lives are affected, and shows the impact it can have on health services and the wider economy.”

“Our research confirms that public health policy should continue to be directed at preventing diarrhoea and vomiting by promoting good personal and food hygiene,” she urged.

Andrew Wadge, FSA’s Chief Scientist, agreed:

“This new study is very important as it gives us a more accurate picture of the impact of IID on the UK population. The study shows the FSA is correct to make campylobacter a key priority in its strategic plan. We know that levels of campylobacter on chicken are far too high in the UK, which is why we are working closely with the food industry to bring these levels down.”

“We are also funding research on norovirus, which was identified as one of the most common causes of illness,” he added.

Wadge said the study confirmed that there is a substantial burden of IID in the UK, but also pointed out much of can be avoided with good hygiene, and following the FSA’s advice should minimize the risk of illness from foodborne bacteria and viruses.

Click here for more information on FSA Safety and Hygiene.

Written by Catharine Paddock PhD