When we try to understand the well-being of a country’s population, there is a powerful explaining variable beyond GDP per head that correlates with many significant indicators of:

  • Health (such as life expectancy, infant mortality, prevalence of obesity, mental illness)
  • Human capital (math & literacy scores, teenage births, high school drop outs), and
  • Social relations (homicide, imprisonment and others)

Economists have established that beyond a minimum threshold needed to provide for populations’ basic needs – food, water, sanitation, shelter, safety – a country’s Gross Domestic Product does not buy a longer lifespan for its population. For example, the US is one of the high GDP per capita countries, spends the most per capita on healthcare, yet falls behind other OECD peer countries (such as France, Japan, Greece, Sweden, New Zealand, and others) in health outcomes.

The mystery variable is economic equality. As British economists Richard Wilkinson and Kate Pickett have shown, higher inequality within OECD countries – and within a US State – is correlated with lower levels for all these indicators of health, human capital and social relations.

Why is that so? One hypothesis is that higher inequality leads to higher status insecurity, which leads to more frequent situations in which we experience social-evaluative stress (i.e. the threat to self-esteem and social status), a type of stressor that consistently raises cortisol and adrenaline levels in our blood.

Such chronically elevated levels of stress hormones have detrimental effects on the body: they shrink brain size, disrupt its proper functioning, elevate the heart rate, raise blood pressure, encourage plaque buildup, disrupt digestive effectiveness, suppress the immunity system and shorten gene telomeres.

Now, when we try to understand the well-being of individuals, explanations are similar. Beyond a minimum level of income sufficient to provide the basics, the variable that consistently relates to positive health and social outcomes is social networks and quality of relationships. A few of the more interesting studies over the past 30 years have shown:

  1. Attachment style: Attachment styles are the crucial building blocks of how people develop relationships throughout life. A large American survey of self-reported attachment styles and physical illness conducted in 2010 found that those with insecure attachment reported more physical illness than securely attached individuals.
  2. Adverse Childhood Experiences: since the 1980ies, large-scale longitudinal studies by the CDC and Kaiser Permanente have shown the long term negative health outcomes of individuals whose family relationships in childhood were severely disrupted or toxic.
  3. Isolation and immunity system: Studies have established that social isolation leads to negative health outcomes via chronic inflammation. A fascinating theory is that in isolation we are more likely to suffer from wounds (as opposed to the viruses brought by close proximity to others), hence our immune system adapts by developing a heightened response to bacteria.
  4. Blue Zones: Three out of the nine common characteristics of centenarians in the world’s Blue Zones have to do with social relationships.

In summary, the cornerstone of human health seems to be the quality of our relationships, from birth onwards.