Eating sweets as a child increases your risk of violence thirty years later, according to almost every single media outlet today (the BBC, the Daily Mail, the Daily Express, The Independent, the Daily Mirror, The Sun, the Daily Record, and the Herald).

A popular story, then, but how true can it possibly be? Julian Hunt of the Food and Drink Federation called it “either utter nonsense or a very bad April Fool’s Day joke”.
 
The press reports accurately summarise the claims made in a paper in British Journal of Psychiatry by a team from Cardiff University led by Dr Simon Moore (vol 195, pages 366-367). The researchers used data from the British Cohort Study which has tracked babies born in a single week in April 1970, with follow-up interviews when they were  5,10, 16, 26, 30, 34 and 42.
 
Sweet consumption at the age of 10 showed a correlation with convictions for violence between the ages of 30 and 34. Those who ate confectionery daily at the age of 10 were more than three times as likely to have been convicted of a violent offence as those who ate it less often or not at all.
 
The authors call the link “novel and robust”. But questions arise from other links their research threw up. For example, “late birth” (undefined) shows an even stronger link to violence than eating sweets, and having been screened by a health visitor during childhood a strongly protective effect. Is it realistic to believe that being visited by a health visitor before the age of five reduces the risk of later violence by more than a third? Or that having access to a car at the age of 34 reduces violent offending by a factor of four?
 
The number of violent people in the sample was small, which complicates the statistical analysis. The authors are bashful about revealing the total number, but say it was 0.47 per cent of the sample, which appears to have numbered 6,942. If so, the conclusions are based on just 33 people with convictions for violence.
 
Put that way, it doesn’t sound very convincing to me. It isn’t April 1, so I’d settle for utter nonsense.