Having high blood pressure or high cholesterol before age 55 can have a lasting impact on your risk of heart disease in later life -- even if you subsequently lower your levels, a study published in the journal PLoS ONE has said.

The researchers had conducted a three-sample Mendelian randomisation analysis using data from the UK Biobank including 136,648 participants for LDL-C (low-density lipoprotein cholesterol), 135,431 participants for SBP (systolic blood pressure), and 24,052 cases for CHD (coronary heart disease) to assess the effect of duration of exposure to the risk factors on risk of CHD.

They discovered that when high LDL-C and SBP levels could be predicted using genetics, there was an increased risk of coronary heart disease, regardless of age at diagnosis.

They also stated that those with elevated SBP and LDL-C levels in their early to midlife years were at a greater risk of coronary heart disease, regardless of their SBP and LDL-C levels later in life.

In addition, they mentioned that coronary heart disease is often caused by a person's cumulative exposure to risk factors such as SBD and LDL-C, which can have long-term consequences on a person's risk.

"These findings support the importance of lifelong risk factor control in young individuals, whose risk of CHD accumulates throughout life," said the researchers.

Moreover, the researchers proposed that treating young people with increased SBP and/or LDL-C is critical in order to reduce accumulated exposure over their lives.

"Our findings suggest that old age alone should not be a reason to withhold otherwise appropriate LDL-C and BP-lowering treatments, because the effect of genetically mediated LDL-C and SBP on the incident risk of (coronary heart disease) is consistent throughout life," they wrote.