Genetics, race, ethnicity, and health

doi:10.1136/bmj.328.7447.1070

From trainee to consultant, BMJ Group offers doctors around the world tailored information, special events, learning resources and recruitment services at every step along their career path.

... by doctors, for doctors, for patients
We are open for entries!

Online learning

BMJ Learning

High-quality CME / CPD for doctors and other healthcare professionals. BMJ Learning features hundreds of accredited, peer-reviewed learning modules in text, video, and audio formats. Find out more

Courses and Qualifications

BMJ Masterclasses

BMJ Masterclasses, led by experts, help clinicians to use the latest evidence and recent guidelines in practice and meet their CPD/CME requirements. Find out more

Exam Preparation

The leading provider of online exam preparation, helping over 167,000 healthcare professionals to pass their exams. Find out more

onExamination

Search all BMJ education articles:

From

Limit by

Access to the full text of this article requires a subscription or payment. Please log in or subscribe below.

Neil Pearce, professor (n.e.pearce@massey.ac.nz)1,
Sunia Foliaki, research fellow1,
Andrew Sporle, research fellow2,
Chris Cunningham, professor3

¹Centre for Public Health Research, Massey University Wellington Campus, Private Box 756, Wellington, New Zealand
²Department of Statistics, University of Auckland, Private Bag 92019, Auckland, New Zealand
³Te Pûmanawa Hauora, School of Maori Studies, Massey University

Correspondence to: N Pearce

Accepted 25 February 2004

Genetics plays only a small part in ethnic differences in health, and other factors are often more amenable to change

In the past few decades spectacular advances have occurred in molecular biology techniques. Researchers have been eager to use these new techniques to study ethnic or racial differences in health that are commonly assumed to have genetic causes. We argue that this assumption is based on confusion between three very different concepts: genetics, race, and ethnicity. This is invalid both scientifically and in terms of public health policy. We concentrate on research in Maori and Pacific (Polynesian) people, but the issues considered are of more general relevance.

Genotypes and phenotypes

It is a common misconception that the genotype determines the phenotype. Genetic factors do have a large influence on health, but they are just one piece of a much larger picture. We are all continuously developing throughout our lives with a constant interaction between our genes and the environment.1 Any discussion of genetic tendencies thus makes assumptions about who is normal and what is a normal environment.2 For example, some researchers have argued that Polynesians have a thrifty genotype with a greater tendency towards obesity and non-communicable diseases such as diabetes when they adopt a European diet.3 It now seems, however, that almost everyone except Europeans may have the thrifty genotype.4

Genetics, heritability, and the environment

The constant interaction between genes and the environment means that few diseases are purely hereditary (even if they are genetic). Purely hereditary diseases are very rare (1/2300 births for cystic fibrosis, 1/3000 for Duchenne's muscular dystrophy, and 1/10 000 for Huntington's disease) and account for a small proportion of overall disease.2

It is often assumed that diseases are genetic because they run in families, but this often reflects a common environment and lifestyle rather than a genetic …