Health – it’s all relative

Why does Japan have the highest life expectancy and one of the best health systems, yet less than 50% of the population consider their health to be good or very good (one of the lowest scores in OECD countries)? What is health; is it the absence of a negative (disease, pain) or is it a positive concept?

Health can be measured and quantified objectively (with things like life expectancy, body mass index and blood sugar levels) or subjectively, by asking people how healthy they think they are. Objective measures provide hard data that can be useful, but they do not tell us much about how the patient perceives their own health. For this we use terms like Health-Related Quality of Life, a concept closer to things like life-satisfaction, happiness and subjective well being. It is argued that this (subjective measure) is the most important measure of health.

It turns out that self-rated health is surprisingly constant over time (despite changes in objective health), because reporting of health is relative.

Wealth, like health, is also relative. People do not change their perception of their own wealth, despite increases in average buying power and overall wealth over time. Their perception of wealth is completely tied to with how they rank their wealth relative to those around them.

Amartya Sen published in the BMJ in 2002 that poorer populations with the least medical care and shortest life expectancy have lower rates of reported illness (better subjective health). This is possibly because of an acceptance of ‘symptoms’ as a normal part of life. Perception of health is influenced by expectations, and those expectations are determined by the environment.

In the above example, if you were to rate the health of the average person in the poorest areas, you would probably rank it very low. That ranking, however, is based on your own expectations and experience, not theirs. Similarly, if you were asked to rate the general health of a person with a permanent spinal cord injury (in a wheelchair, with no control of bladder of bowel function), you might give them a score of 2 or 3 out of 10 for health, but you would be comparing this to your own health. Such patients rate their own overall health, vitality, mental health and social functioning as pretty close to the community average (here).

Now transpose the situation to a different time period. In the 1800’s life expectancy was less than 50, there was no effective medicine, and work meant long hours of back-breaking labour. Even 100 years ago this was the case for many. How would people have rated their health or quality of life then? Probably no different to now, because they were comparing themselves to their contemporaries. What about 1,000 or 10,000 years ago? I would be willing to bet that the average proportions of time spent laughing and spent crying were about the same as they are now.

Despite some correlation between income and happiness (up to a point), for as long at it has been measured, average happiness has not increased despite increases in life expectancy and net worth (here). Similarly, average self-rated health has not changed over time. So health and happiness are a bit like height: average height has (objectively) steadily increased over time, but at any time, the proportion of people who consider themselves ‘short’ or ‘tall’ remains the same.

The bottom line

Subjective (self-rated) health remains relatively constant, despite living longer, disease-free lives, because it is essentially a ranking system. Some people rank themselves high, and some low, but the average always stays about the same. Our expectations and our ability to cope are predictors of health, not just things that might be interpreted (by others) as ‘symptoms’.

What does this mean for us? It means that we do not need to have every negative predicament medicalised, by turning them into symptoms that demand diagnosis and relief; we can also be healthy by learning to cope with life’s predicaments.