Editorials

Health inequalities and cystic fibrosis

BMJ 2011; 343 doi: http://dx.doi.org/10.1136/bmj.d4818 (Published 23 August 2011) Cite this as: BMJ 2011;343:d4818
  1. David Taylor-Robinson, Medical Research Council population health scientist1,
  2. Michael S Schechter, associate professor2
  1. 1Department of Public Health and Policy, University of Liverpool, Liverpool L69 3GB, UK
  2. 2Department of Pediatrics, Emory University School of Medicine and Children’s Healthcare of Atlanta, Atlanta, GA, USA
  1. david.taylor-robinson{at}liverpool.ac.uk

Even for genetic diseases, social conditions are still important determinants of outcome

Cystic fibrosis is the most common serious inherited disease in white populations. Intensive support from family and healthcare services is needed from the time of diagnosis onwards, and most patients die prematurely from respiratory failure. Survival has dramatically improved over successive birth cohorts, such that British children born in the 21st century will have a median survival of over 50 years.1 However, disease progression and survival still vary greatly, mostly as a result of social and environmental, rather than genetic, determinants.2 It has been known for more than 20 years that people with cystic fibrosis from socioeconomically disadvantaged backgrounds die younger than those in more advantaged positions.3

In a linked observational study (doi:10.1136/bmj.d4662), Barr and colleagues used death registration data in England and Wales to show that this socioeconomic divide in premature mortality in cystic fibrosis has persisted with no substantial narrowing for over four decades.4 They also show that female patients continue to die at a younger age than men. What can we learn from this, and what are the implications for policy and for clinicians?

Cystic fibrosis offers a valuable case for understanding how health inequalities develop. It is an autosomal recessive disease with an asymptomatic (and, until recently, undetectable) carrier state, so unlike many other diseases, socioeconomic status does not influence who gets the disease. Inequalities related to socioeconomic status result from the different patterns of exposure to harmful and protective or therapeutic influences that occur over the course of people’s lives. Studies from the United States and United Kingdom show that significant inequalities in key intermediate outcomes in cystic fibrosis, such as growth and lung function, begin early in childhood and persist over time.5 6 The early appearance and persistence of inequalities support the need for interventions that are targeted at the early (and perhaps prenatal) years and reinforce the importance of screening for cystic fibrosis in newborns. This, incidentally, is also true for sex related inequalities, which are probably caused as much by socially determined gender roles as by biologically determined sex characteristics.7

A key question for practising clinicians is what role healthcare delivery plays in mitigating or potentiating health inequalities in cystic fibrosis. In the US, studies have failed to identify important socioeconomic status related differences in the use of chronic treatment for cystic fibrosis, treatment of pulmonary exacerbations, or hospital admissions,2 5 8 although there is some evidence that affluent groups may be earlier recipients of newly developed cystic fibrosis drugs.8 The adoption of system based methods to optimise consistency in the use of best care practices might help to minimise variations in prescribed care.9 Other than tackling any residual socioeconomic status related differences in access and provision of healthcare to patients with cystic fibrosis, how else can inequalities be reduced?

Some underused tools are available to cystic fibrosis clinicians. One obvious target for action is to protect newly diagnosed children from environmental tobacco smoke. There are striking and persistent differences in the prevalence of smoking according to socioeconomic status.10 Exposure to environmental tobacco smoke is associated with poorer growth and lung function in cystic fibrosis,2 and it may be the most important explanatory factor for inequalities related to socioeconomic status in this disease.11 Early identification of family members who smoke, and appropriate counselling and referral to smoking cessation services, would be an effective intervention for all patients, regardless of social position. This should be coupled with support to develop disease self management skills in the patient and the family,12 in addition to targeted input from social workers who work with the multidisciplinary cystic fibrosis team.

Ultimately, however, although individually focused interventions may have some limited success, the more effective long term solution to health inequalities in people with cystic fibrosis and in the general population is likely to be one that takes broader action to tackle the social determinants of health. These are the “conditions in which we are born, grow up, work, and live,” and they include income and income distribution, education, employment and working conditions, housing, food insecurity, race and ethnicity, and sex and gender roles. These factors provide a particularly important context for a family dealing with the stresses of caring for a child with a complex chronic illness like cystic fibrosis over a lifetime.

The evidence is clear, unfortunately, that we have made little progress over the past few decades in reducing health inequalities generated by social gradients,11 and this evidence is strengthened by Barr and colleagues’ study. Future research should assess the mechanisms that generate socioeconomic status related inequalities and the interventions that are most likely to reduce them, bearing in mind that investigating interventions at the population level is likely to have greater impact. The current political discourse in the US suggests that any insight into effective social interventions is unlikely to come from that side of the Atlantic; the discussion on the UK side, inspired by documents such as the Marmot report,11 will hopefully provide a first step towards investigating and putting into practice the most effective ways to reduce the socioeconomic gradient in health.

Notes

Cite this as: BMJ 2011;343:d4818

Footnotes

  • Research, doi:10.1136/bmj.d4662
  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Provenance and peer review: Commissioned; not externally peer reviewed.

References