The definition of quality of life as stated by the WHOQOL working group^(1)^ is reproduced below:
Quality of life is an individuals’ perceptions of their position in life in the context of the culture and value systems in which they live, and in relation to their goals, expectations, standards and concerns. It is a broad ranging concept affected in a complex way by the persons’ physical health, psychological state, level of independence, social relationships and their relationship to salient features of their environment.
We may be tempted to add those questions raised by Elkinton^(2)^ some fourty years ago
How does the physician protect the proper quality of life of the individual patient? How can the quality of life be improved…? Into which programs of preventive and therapeutic medicine should the resources of society be put to achieve the maximum in health and quality of life for all members of that society?
An historical account of HRQL research can be found in the review of Medina et al.(3)
From a psychological perspective, two questions (at least) are to be answered by the researcher: (a) what factors impact HRQL, and (b) what factors impact its subjective reporting.
Now, the NIH has prescribed that all research projects about health disparities or epidemiological studies in general must include minorities to the extent that it seems appropriate to the study under consideration. The same applies in clinical trials, unless researchers are seeking a very homogeneous group of patients.
In genetic epidemiology, for instance, it is common to consider “culture” a one of the main covariate. I quoted the term culture since we more often see words like ethnicity or ancestry in place of culture or even race. Following the IOM^(4)^ definition, race encompasses inter-individuals variations at both the biological and behavioral level, but see Hernandez and Blazer^(5)^ (Chapter 5) for an extended discussion on this topic.
Shields et al.(6) recommend avoiding the term of race although race and ethnicity appear to bear some explanatory power when predicting disease risk (in mental or more common health problems):
(…) with the exception of the health disparities context, in which self-identified race remains a socially important metric, race should be avoided or used with caution and clarification, as its meaning encompasses both ancestry… and ethnicity (…)
Chapter 4 (M. Bullinger, S. Schidt, and D. Naber) is entirely devoted to the development of health-related instruments across cultures.
The authors also make a clear distinction between functional impairments as reported in most HRQL instrument and the subjective consequences of these functional limitations. Moreover, “in order to fully capture the concept (of quality of life), health status measurements should be operationalized both via clinical information and self-reports, which is in line with the classical approach to health indicator research.” (p. 70).
- WHOQoL Group. Study protocol for the World Health Organization project to develop a quality of life assessment instrument (WHOQOL). Quality of Life Research, 1993, 2: 153-159.
- Elkinton, JR. Medicine and the quality of life. Annals of Internal Medicine, 1966, 64(3): 711-714.
- Medina, A, Moreno, MJ, Segura, C, Lillo, R, and Dening, TR. Quality of life and medicine: a historical note. History of Psychiatry, 1996, 7(26): 225-229.
- IOM (Institute of Medicine). The Unequal Burden of Cancer: An Assessment of NIH Research and Programs for Ethnic Minorities and the Medically Underserved. Washington DC: National Academy Press, 1999.
- Hernandez, LM and Blazer, DG (Eds). Genes, Behavior, and the Social Environment: Moving Beyond the Nature/Nurture Debate. National Academies Press, 2006.
- Shields, A, Fortun, M, Hammonds, EM, King, PA, Lerman, C, Rapp, R, and Sullivan, PF. The use of race variables in genetic studies of complex traits and the goal of reducing health disparities: A transdisciplinary perspective. American Psychologist, 2005, 60(1): 77-103.