14 August 2012
A Melbourne study of twins has found that identical twins were almost twice as likely to faint compared with non-identical twins, suggesting that fainting is caused by complex genetic and environmental factors.
Recruited from the Australian Twin Registry, 51 sets of twins of the same gender aged 9 to 69 who had a history of fainting completed a phone questionnaire.
More than half (57 per cent) reported typical fainting triggers including exposure to blood, injury, medical procedures, prolonged standing, and pain.
Identical twins reported more episodes of fainting and more environmental triggers to fainting than non-identical twins.
The frequency of fainting in non-twin relatives was low, suggesting that fainting was not inherited through a single gene, the authors said.
Last Reviewed: 14 August 2012