Lack of popularity and influence may have a long term effect
Children who impress their peers at school tend to go on to enjoy better health as adults, research suggests.
The study was based on a 30-year follow-up of more than 14,000 children born in Sweden in 1953.
The Journal of Epidemiology and Community Health study found the least popular children had a nine times higher risk of ischaemic heart disease.
They were also more at risk of diabetes, drug, alcohol and mental health problems.
The degree of popularity, power and status enjoyed by each child was assessed when the children reached sixth grade in 1966 by asking them who they most preferred to work with at school.
Marginalised (no nominations)
Peripheral (one nomination)
Accepted (two to three nominations)
Popular (four to six nominations)
Favourite (at least seven nominations)
Individual children were categorised into five status bands depending on how many nominations they received.
The researchers then matched up this data against information on hospital admissions between 1973 and 2003.
For both men and women, the children who were furthest down the pecking order at school had the highest overall risk of serious health problems as an adult.
For instance, they were more than four times as likely to require hospital treatment for hormonal, nutritional and metabolic diseases as the most popular children.
And their risk of mental health problems was more than doubled.
The researchers said the findings could not be explained by social class.
Lead researcher Ylva Almquist, from the Centre for Health Equity Studies at the University of Stockholm, said children with a low status might lack social support, and be starved of information.
This could lead to a more negative self-image, which could lead to lower expectations, stunted ambition - and poor choices in life.
"For example, children in lower peer status positions may adopt a more health-damaging lifestyle, including behaviours such as heavy smoking and drinking.
"These behaviours are known to be major risk factors for heart diseases."
Ms Almquist said it was possible that some children's popularity was a result of poor health - but the effect found in the study was too broad for this to be the only factor.
She said the study suggested that schools should work to foster social equality in the classroom, and to boost children's self-image.
Professor Alan Maryon-Davis, president of the UK Faculty of Public Health, said: "Children who feel undervalued or are bullied at school often grow up lacking self-confidence.
"They then seek comfort in over-eating, smoking or drinking to excess, and all too often find themselves on the slippery slope to chronic ill-health.
"It is crucial to do whatever we can to help children and young people feel valued."