HOME to around a fifth of the world鈥檚 population, China should be a treasure trove as far as the studies on genetic roots of disease are concerned. But too often, what reaches the west is fool鈥檚 gold 鈥� describing spurious links between the possession of particular DNA sequences and susceptibility to serious conditions such as cancers.
That鈥檚 the conclusion of a team led by John Ioannidis from the University of Ioannina in Greece, who surveyed published studies on 13 different proposed links between genes and disease. 鈥淢isleading information may lead to unnecessary genetic testing of millions of people,鈥� he says. And that could have worrying implications, particularly if people bearing 鈥渞isky鈥� genes are denied health or life insurance.
鈥淭he studies were more likely to show positive associations between genes and disease鈥�
Advertisement
Ioannidis found that the Chinese studies were more likely to throw up positive associations between genes and disease. And the effect was most marked in studies that were indexed in PubMed, the main database of the biomedical literature (Public Library of Science Medicine, DOI: 10.1371/journal.pmed.0020334). Ioannidis blames a failure to publish Chinese studies that show no link. One answer would be for health experts to disregard Chinese studies. But this would be a mistake, he warns. Ignoring the world鈥檚 most populous nation makes little sense, he says. And in any case, the biased publication of 鈥渟pectacular鈥� results is scarcely unique to China. 鈥淭his is a problem of global dimensions,鈥� says Ioannidis.
Instead, Ioannidis wants researchers to battle such biases by banding together to share their unpublished data.
In October, 27 consortia such as these met in Cambridge, UK, in a pioneering effort to share their experiences. But they are a rarity, especially where common diseases such as diabetes are concerned. And the consortia formed so far contain few Chinese researchers.
