Two US researchers began to find hard evidence for it in Manitoba nearly 40 years ago, and over 70 large-scale studies have since extended the relevance of their discovery: you are likely to be as well – and as close to death – as you feel.

The growing importance of self-assessment of health and circumstances was the theme of Harvard Professor Joshua Salomon's presentation to this year's conference of the International Society for Quality of Life Research (ISOQOL) in New Orleans.

To a degree, he was preaching to the converted, because the conceptual shift from a largely disease- and mortality-focused view of health in favor of more holistic, subjective stance underpinned much of the proceedings.

Nevertheless, when organizations and researchers thought about health, Salomon argued, their attitudes typically boiled down to two questions: how healthy was the average person in a population, be it a school, community or nation, and what were the main causes of ill-health? 

Much before Jana Mossey and Evelyn Shapiro made their seminal study of mortality among the elderly in Manitoba, researchers were likely to respond with a barrage of mortality data. The data would indicate how long the average person was likely to live and what would be the most likely causes of death. So the face of death was intended to provide a picture of the living. 

But ask the same researchers to say what they thought about the living, based on their own subjective opinion of their own health, and they were likely to insist that such a view was unreliable and irrelevant. 

However, as a result of the Manitoba study and the more recent work it had inspired, Salomon said, self-reported health was making an acknowledged contribution to the World Health Organization’s International Classification of Functioning, Disability and Health (ICF).

It emphasized the importance and interaction of biological functions; activity and participation were central components, and environmental and social influences played a strong role.

Self-reported psychological and physical health, together with social and environmental factors were now included in the broadened concept of “quality of life,” which was regarded as being as significant as traditional “objective” clinical and mortality-based indicators. 

But, as Saloman explained, with this progression came new challenges and complexities. Seemingly similar individuals living in comparable nations reported big differences in their quality of life. It needed to be established how much of the variation was due to “true” difference and how much to the relative value and meaning people attached to the various components of health so redefined?

The size of the difficulty and the potential reward became clearer later in the day, when the discussion focused on the interplay between the biological, the psychological, the social and the societal dimensions of health. 

Emotional and behavioral components are vital to understanding children’s health and the evidence of a downward trend in their psychological well-being, has led some commentators to speak of “millennium morbidity”. 

Limitations in our understanding of comparisons between countries began to be tackled in 2004 by the Kidscreen Group, and progress along that avenue was described by Luis Rajmil from the Catalan Agency for Health Technology Assessment in Barcelona. 

With European Commission support, The Kidscreen Group set out to measure the health-related quality of life of children between the ages of eight and 18 across 13 European Countries, Rajmil said. 

Nationally representative samples of over 20,000 children and parents completed a culturally harmonized Kidscreen questionnaire. 

Wide variation was uncovered, leading to controversial and widely published announcements that child quality of life was lowest in the UK, Spain, France and Poland and highest in the Netherlands.

So why the variation? One distinct possibility, Rajmil explained, was the influence of socio-economic status. The previous generation of studies had found that poverty and poor physical health conspired to bring about early death. Joshua Salomon’s argument implied a similar connection between perceptions of poverty and self-reported poor mental health. And the Kidscreen evidence supported that extension of the equation. 

It was not only absolute levels of deprivation that made the difference. Perceived inequalities of wealth within nations had a marked effect on children’s subjective quality of life. In countries where the inequalities of wealth were greatest and more visible, children were likely to have a poorer subjective quality of life – and with damaging consequences.

For the seminal Manitoba study, see: Mossey J M, and Shapiro E "Self-Rated Health: A Predictor of Mortality among the Elderly." American Journal of Public Health 72, no. 8 (1982): 800–808.