Sickle-cell disease is a blood condition that affects people's red blood cells. The cells are less able to carry oxygen, become stiff and sticky and can clump together blocking blood flow, causing severe pain and potential organ damage. A new study of 196 people by researchers at the National Heart, Lung and Blood Institute in the U.S. suggests that even people with few or mild complications of the disease could have worse cognitive function than unaffected people. The study compared 149 adult sickle-cell patients aged between 19 and 55 with 47 healthy participants. On average the scores for the sickle-cell patients were in the normal range but twice as many of the sickle-cell patients scored below normal levels in tests of intellectual ability, short-term memory, processing speed and attention. Those sickle-cell patients who scored lower were more likely to be older and have lower haemoglobin levels but none of the differences in brain function could be explained by the influence of other diseases (as the sickle-cell patients were otherwise relatively healthy) or changes to brain structure.
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