<p>Both high and low levels of high-density lipoprotein (HDL) cholesterol - commonly called 'good cholesterol' for helping reduce the risk of stroke and heart attack - may increase a person's risk of premature death, a new study has claimed.<br /><br /></p>.<p>Conversely, intermediate HDL cholesterol levels may increase longevity, researchers said.<br />"The findings surprised us. Previously it was thought that raised levels of the good cholesterol were beneficial," said Ziyad Al-Aly, professor at Washington University in the US.<br /><br />"The relationship between increased levels of HDL cholesterol and early death is unexpected and not fully clear yet. This will require further study," said Al-aly.<br /><br />Cholesterol is a fatty substance found in blood that can narrow and block heart vessels, causing cardiovascular disease and stroke. For years, HDL cholesterol has been credited with helping to remove plaque-building "bad cholesterol" from arteries, researchers said.<br />They studied kidney function and HDL cholesterol levels in more than 1.7 million male veterans from October 2003 to September 2004. Researchers then followed participants till September 2013.<br /><br />Patients with kidney disease frequently have lower levels of HDL cholesterol, which might explain their increased risk of early death; however, the association between elevated HDL cholesterol levels and premature death in these patients has been unclear, researchers said.<br /><br />In this study, researchers showed that both high and low HDL cholesterol levels were associated with an increased risk of dying among study participants with all levels of kidney function.<br /><br />"The findings may explain why clinical trials aimed at increasing HDL cholesterol levels failed to show improved outcomes," said Al-Aly.<br /><br />Research data showed a relationship between HDL cholesterol levels and mortality as a U-shaped curve with the risk of death increased at both ends of the spectrum.<br /><br />"Too low and too high are both associated with higher risk of death," said Al-Aly.<br />The findings were published in the Clinical Journal of the American Society of Nephrology<br />.</p>
<p>Both high and low levels of high-density lipoprotein (HDL) cholesterol - commonly called 'good cholesterol' for helping reduce the risk of stroke and heart attack - may increase a person's risk of premature death, a new study has claimed.<br /><br /></p>.<p>Conversely, intermediate HDL cholesterol levels may increase longevity, researchers said.<br />"The findings surprised us. Previously it was thought that raised levels of the good cholesterol were beneficial," said Ziyad Al-Aly, professor at Washington University in the US.<br /><br />"The relationship between increased levels of HDL cholesterol and early death is unexpected and not fully clear yet. This will require further study," said Al-aly.<br /><br />Cholesterol is a fatty substance found in blood that can narrow and block heart vessels, causing cardiovascular disease and stroke. For years, HDL cholesterol has been credited with helping to remove plaque-building "bad cholesterol" from arteries, researchers said.<br />They studied kidney function and HDL cholesterol levels in more than 1.7 million male veterans from October 2003 to September 2004. Researchers then followed participants till September 2013.<br /><br />Patients with kidney disease frequently have lower levels of HDL cholesterol, which might explain their increased risk of early death; however, the association between elevated HDL cholesterol levels and premature death in these patients has been unclear, researchers said.<br /><br />In this study, researchers showed that both high and low HDL cholesterol levels were associated with an increased risk of dying among study participants with all levels of kidney function.<br /><br />"The findings may explain why clinical trials aimed at increasing HDL cholesterol levels failed to show improved outcomes," said Al-Aly.<br /><br />Research data showed a relationship between HDL cholesterol levels and mortality as a U-shaped curve with the risk of death increased at both ends of the spectrum.<br /><br />"Too low and too high are both associated with higher risk of death," said Al-Aly.<br />The findings were published in the Clinical Journal of the American Society of Nephrology<br />.</p>