LONDON, Sept 15 (Reuters) - Heart disease and tobacco ranked with conflict and violence among the world’s biggest killers in 2016, while poor diets and mental disorders caused people the greatest ill health, a large international study has found.

The Global Burden of Disease (GBD) study, published on Friday in The Lancet medical journal, found that while life expectancy is increasing, so too are the years people live in poor health. The proportion of life spent being ill is higher in poor countries than in wealthy ones.

“Death is a powerful motivator, both for individuals and for countries, to address diseases that have been killing us at high rates. But we’ve been much less motivated to address issues leading to illnesses,” said Christopher Murray, director of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, which led the study.

He said a “triad of troubles” – obesity, conflict, and mental illness - is emerging as a “stubborn and persistent barrier to active and vigorous lifestyles”.

The IHME-led study, involving more than 2,500 researchers in around 130 countries, found that in 2016, poor diet was associated with nearly one in five deaths worldwide. Tobacco smoking killed 7.1 million people.

Diets low in whole grains, fruit, nuts and seeds, fish oils and high in salt were the most common risk factors, contributing to cases of obesity, high blood pressure, high blood sugar and high cholesterol.

The study found that deaths from firearms, conflict and terrorism have increased globally, and that non-communicable, or chronic, diseases such as cardiovascular disease and diabetes caused 72 percent of all deaths worldwide.

Heart disease was the leading cause of premature death in most regions and killed 9.48 million people globally in 2016.

Mental illness was found to have a heavy toll on individuals and societies, with 1.1 billion people living with psychological or psychiatric disorders and substance abuse problems in 2016.

Major depressive disorders ranked in the top 10 causes of ill health in all but four countries worldwide.

The GBD is funded by the Bill & Melinda Gates Foundation global health charity and gives data estimates on some 330 diseases, causes of death and injuries in 195 countries and territories.