Research Note: Twin studies and their value for physiotherapy research

摘要

Twin studies have been designed and implemented since the late19th century. Although relatively new and underused in physiotherapy research, they have made a scientific impact on understanding the possible extent of genetic causes behind human traits.1–4The initial applications of twin studies to health and disease weremainly aimed at elucidating the influences of nature versus nurture.More recently, a variety of modern and simple, yet sophisticated, twinresearch designs have been developed and applied to unravel causesof and cures for diseases and to make significant contributions to theunderstanding of how psychological and biological traits are formed.Put simply, the availability of data from a family member, in thiscontext a sibling co-twin who shares some or all genetic material andother familial factors with the relevant individual, offers immensepossibilities for understanding genetic and other familial influences,controlling for familial confounding, by applying statistical andmodelling approaches that are not possible with a non-twin design.Essentially, twin studies can double or amplify the research horizonand provide novel scientific insights into the health of twins and nontwins.