Grandparents 'are a cancer risk for their grandchildren'
Grandparents are a potential health hazard for children and may even increase their risk of cancer, say scientists.
They spoil their grandchildren with sweet "treats" and big helpings of fattening food, and expose their young lungs to second-hand tobacco smoke, it is alleged.
The extraordinary claims are based on a review of research into the influence grandparents have on lifestyle factors that can sow the seeds of cancer in later life.
Lead author Dr Stephanie Chambers, of the University of Glasgow, said: "While the results of this review are clear that behaviour such as exposure to smoking and regularly treating children increases cancer risks as children grow into adulthood, it is also clear from the evidence that these risks are unintentional.
"Currently, grandparents are not the focus of public health messaging targeted at parents and in light of the evidence from this study, perhaps this is something that needs to change given the prominent role grandparents play in the lives of children."
Previous research has looked at the way parents can affect their children's susceptibility to cancer and other diseases, but less attention has been paid to the role of part-time carers such as grandparents, said the scientists.
The team analysed data from 56 studies from 18 countries that included information about the influence of grandparents on their grandchildren.
Overall, grandparents were found to have an adverse effect - despite meaning well. In many cases, such as rewarding good behaviour with sweets, they were putting the health of their grandchildren at risk with kindness.
Smoking, poor diet, excess weight and lack of physical activity were all known to increase the risk of cancer, said the researchers.
Factors associated with long-term cancer risk were first experienced within the family setting. Social trends, such as the growing proportion of women in the workforce, rising childcare costs, and increasing numbers of single parents, had meant that more children were being placed in the care of their grandparents.
The research found that "excessive feeding" of children was a significant grandparent problem, as was providing meals made from scratch but with unhealthy ingredients.
Sweets were used to reward, express love, or strengthen the bond between grandparent and child. There was also evidence that the poverty and hunger some grandparents experienced themselves as children led them to believe extra weight was a sign of good health.
Grandparents smoking in the home was identified as having a negative impact, both by setting a bad example and exposing children to second-hand tobacco smoke.
The findings are published in the online journal 'Public Library of Science ONE'.