The longer a person spends being obese, the higher is the risk of a "silent" heart damage, finds a study, which says "the number of overweight or obese years may "add up" to the risk.

The findings showed that for each 10 years that a person spends being obese, the risk of having high levels of troponin -- a protein linked with heart damage -- increased 1.25 times, even when accounting for heart disease risk due to high blood pressure, diabetes and kidney disease. Troponin is released when the heart muscle has been damaged. The more damage there is to the heart, the greater will be the amount of troponin in the blood.

Thus, maintaining a healthy weight across the lifespan is important for keeping the heart healthy and minimising damage as people age, the researchers said. "We're finding that people's weight from age 25 onwards is linked to the risk of more or less heart damage, as measured by levels of the protein troponin, later in life, which underscores the likely importance of long-term weight control for reducing heart disease risk," said Chiadi Ndumele, Assistant Professor at the Johns Hopkins University.

"The study suggests that even in the absence of such heart disease risk factors as high blood pressure, diabetes or kidney disease, the number of years spent obese or overweight contributes to the higher likelihood of heart damage," Ndumele added. For the study, appearing in the journal Clinical Chemistry, the team examined 9,062 participants, four times over a period of 10-11 years.

Those who increased their body mass index (BMI) to the overweight and obesity range at the fourth visit were 1.5 times more likely to have increased troponin levels of at least 14 nanograms per litre, indicating heart damage. On average, each 100 extra BMI-years increased the likelihood, or risk, of increased troponin by 21 per cent, Ndumele said.