That a child born in Sierra Leone has less promising health prospects than an American peer is nothing new. But that getting a job promotion can significantly reduce our chances of dying is a less obvious fact.

Health gradient

According to the Withehall study of British civil servants between the ages of 20 and 64, those at the bottom of the hierarchy (couriers, porters, etc.) had three times the mortality rate of those at the top (e.g. administrators). Even removing the standard risk factors (age, smoking, diet etc.), the mortality ratio was still 2.1.This is what Michael Marmot, author of the study, called a ‘health gradient’.

The concept is by no means new (the study dates back to the early 1990s) but seems to have been completely overlooked by our society. Not a insignificant oversight, which risks undermining many of the efforts made by national health systems – and international bodies – to ensure the health of their citizens. Including the campaign against Covid-19.

The social conditions of an individual – not just the population in which he or she lives – have a decisive influence on many health factors, such as the likelihood of contracting diseases, the spread of infections, the effect of drugs, the impact of diseases, the degree of adherence to treatment, the level of prevention and the consequences that containment measures such as quarantine can have on health status.

So much for not considering them as a key factor in global and local health strategies.

Income and health

As is well known, life expectancy in poorer countries is significantly lower than in developed countries and the likelihood of falling ill is proportionately higher. People born in Japan or Hong Kong have almost 85 years of life ahead of them while in the Central African Republic the average life expectancy is no more than 53 years.

This disparity has many roots, starting with the different chances of contracting a disease. The poorest areas often experience catastrophic outbreaks of viruses that are easily contained elsewhere (the measles virus still causes one million deaths a year in the developing world and is responsible for 44% of deaths among children under 15).

But non-communicable diseases (NCDs) are also different and should be targeted. A committee of The Lancet has developed a special index called the NCDI Poverty, which includes some items specific to the poorest countries, such as snakebite, epilepsy, kidney disease and sickle cell anaemia. For the world’s one billion poorest people, NCDs now account for more than a third of the disease burden, and targeting them with “feasible and affordable” interventions could prevent nearly five million deaths. T

he differences, however, are not limited to the economic gap between nations or geographical macro-areas. Similar considerations can be made for different social groups within the same country. In England, for example, being born in the poorest areas shortens a man’s life expectancy by almost ten years (eight years for women).
This is not surprising when you consider how health status varies according to social conditions. In the United States, the prevalence of obesity among adult women is inversely related to income and varies by ethnic group (see table).

Falling ill with poverty
Source: NCHS, National health and nutrition examination survey, 2017-2018.


This is also the case for the likelihood of infection. Helicobacter pylori (the most common cause of gastritis and ulcers) is more prevalent in lower income groups, but ethnicity also plays an important role: African Americans and Latinos are about twice as likely to be infected as non-Hispanic whites, and even within the three groups there is a gradient that runs in the opposite direction to socioeconomic class, to the point of creating intra-family clusters.
Needless to say, this is not a Stars-and-Stripes peculiarity. In South Korea, a study found that 22% of children were infected with H. pylori, but the prevalence was inversely proportional to socioeconomic status: 12% of children in the richest families, 25% in the middle class and 41% in the poorest groups. Part of the explanation lies in the fact that the immune system needs adequate general health to function optimally. Research has shown that the immune system needs 20-30% more protein and energy in the case of HIV infection (10% in asymptomatic patients).
It is therefore not surprising that inadequate nutrition also plays an important role in immune dysfunction: protein-energy deficiency is estimated to be a major cause of immunodeficiency in developing countries.

Social pressures

It is not just income levels that affect health status. Experiences of racial discrimination have been linked to low birth weight, high blood pressure and poor health. To make matters worse, whites often receive better care. According to the 2019 National Healthcare Quality and Disparities Report, in the US, African Americans, American Indians and Alaska Natives received worse care than whites on about 40 percent of quality indexes; Hispanics received worse care on more than a third of measures.

Similarly, gender-based discrimination has a negative impact on women’s health, with a 30% increase in levels of unhappiness, loneliness and depression. It also has a detrimental influence on their self-perception, making them less likely to feel that they are in excellent (or very good) health and reducing the number of Pap tests, mammograms and clinical breast examinations.

There is also evidence that adolescents who identify themselves as LGBT are more likely to show depressive symptoms, suicidal ideation and self-harm. This phenomenon has been linked to the stress of having a stigmatised identity and to experiences of social rejection.

The contribution of personal relationships

Even setting aside income, social conditions, ethnicity and gender, there may be factors that influence health status within each category. Social relationships, for example, can play an important role in the coping with illness. According to the Swiss scholar Johannes Siegrist, the decision to use or not to use health services comes only after two further stages in the decision-making process: the first is individual and concerns the recognition of a symptom or health problem, but the second involves the circle of acquaintances. At this stage, individuals seek advice from their partner, relatives, friends or other people they trust. Social relationships play an important role in how health complaints are recognised and interpreted.

This hypothesis has been tested in several scientific studies. A meta-analysis found that the influence of social relationships on mortality risk is comparable to that of other known factors: overall, the probability of survival increases by 50 percent with stronger social relationships. Specifically, the ratios were 1.9 for social integration, 1.5 for social networks, 1.4 for perceived social support and 1.2 for received social support. Of course, the presence of a good support network also contributes to better medical outcomes, particularly in chronic cases where the presence of family caregivers can make a substantial difference.

Social epidemiology

Neglecting all of these factors can be fatal to the effectiveness of public health programmes and lead to further inequalities in the population. In California, anti-smoking campaigns have led to significant declines in smoking among citizens, but not across all demographic groups: 19% of Native Americans, 23% of low-income African Americans and 34% of whites who have not completed high school continue to smoke. In fact, the programme has left the most vulnerable groups behind, widening the gap with those in the best circumstances. A similar situation seems to have occurred with the restrictive measures introduced against Covid-19.
A study carried out in Italy by ASLTO3 and the University of Turin has shown that the socio-economic consequences of the lockdown measures seem to affect the most disadvantaged social groups more frequently and more severely. In addition to the medium to long-term health effects (increased morbidity and mortality), they could lead to short-term criticality (particularly in mental health) and the use of unhealthy adaptive and compensatory risk factors, such as unhealthy lifestyles.

A ticking time bomb that could widen the gap between population groups in the future. In addition, the direct impact of the pandemic has been uneven. According to ISTAT data, in March 2020, particularly in areas with a high prevalence of the epidemic, there was a greater increase in mortality rates among the most disadvantaged population segments, which already experienced the highest mortality rates before the epidemic.

Syndemic or pandemic?

Given the importance of pre-existing socio-economic conditions, many observers – including The Lancet – suggest using the term ”syndemic” rather than ”pandemic”. The term was coined in the 1990s by the American anthropologist Merrill Singer to describe the synergistic interaction of health, environmental, social and economic problems and the presence of communicable and non-communicable diseases that severely affect disadvantaged populations.

These situations should be addressed through what is known as ‘social epidemiology’, an approach to health problems that involves the analysis of social experience and examines the mechanisms by which inequalities affect health. As Singer notes, such a strategy can be much more successful than simply controlling epidemic diseases or treating individual patients.

In the words of The Lancet:

‘No matter how effective a treatment or protective a vaccine, the pursuit of a purely biomedical solution to COVID-19 will fail. Unless governments devise policies and programmes to reverse profound disparities, our societies will never be truly COVID-19 secure.