The Global Burden of Disease Study

Lancet 2012;380:2224-2260

These days it is difficult to find a paper published in The Lancet which doesn't have the word global in the title. However the Christmas edition of this journal surpasses itself by devoting all its content to the latest findings from the global burden of disease project. It is the first time the Journal has devoted an entire issue to one study.

This project is an excellent example of big teams answering big questions – and we are talking a big team here with 486 authors from 302 institutions in 50 countries contributing to the papers. The principal findings can be summarized as fewer people are dying but more people are living with disability with chronic disease such as musculoskeletal disorders, mental health disorders and injuries the commonest causes.

One paper is the dauntingly titled “A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010” and that’s before the colon in the title. Why is this important for psychiatrists working at the coal face? Well one of the reasons for justifying increased funding in mental health services is the often quoted prediction that depression will result in the second biggest disease burden in the future. What this paper does is turn the question around and look at what risk factors are important in causing disability rather than what diseases.

What the authors conclude is that high blood pressure, tobacco smoking and alcohol use are the three leading risk factors for global disease burden. This clearly is important for substance use services and should inform policy development and funding in those areas. What about other mental health problems? The way the authors did the study was to pair up risk factors with outcomes. Most of the risk factors were traditional, some would say 19th century, items such as occupational exposure to chemicals paired with specific outcomes. The authors did not look at poverty, social class or inequality as risk factors which I think is a serious omission.

What they did look at was childhood sexual abuse and intimate partner violence paired with depression and self-harm. They found that globally intimate partner violence rated the 23rd most important risk factor and childhood sexual abuse 33rd out of the 43 factors they looked at - however for North America intimate partner violence was 22nd whilst childhood sexual abuse rose to 21st. This illustrates the importance at a population level of managing these risk factors and at an individual level asking about sexual abuse and partner violence. Not doing so is like a cardiologist not asking someone about smoking.

The other six papers in this issue by the same group look at a variety of other measures of global burden of disease. These include global death rates where self-harm (that is suicide) is the 13th most common cause of death globally contributing about 5% of deaths in adults aged 15 to 49. In another paper looking at disability life years lost, globally depressive disorders were the 11th most common cause of disease burden (up from 15th in 1990).