MedicalResearch.com Interview with:
Dr. Kaitlin Wade PhD
Research Associate and Early Career Researcher Representative
Integrative Epidemiology Unit (IEU)
Bristol Medical School (Population Health Sciences)
Faculty of Health Sciences
University of Bristol
MedicalResearch.com: What is the background for this study?
Response: Whilst severe obesity increases the risk of death in the population, there are conflicting results in the literature with some papers suggesting a protective effect of being overweight. Many observational studies also report a J-shaped association between body mass index – a measure of weight accounting for a person’s height – and mortality, where individuals who are underweight also have an increased risk of mortality compared to those within the ‘normal’ range. Such controversial findings are not without limitation, as bias by age, ill-health and other lifestyle factors are likely. One method to overcome the limitations of observational studies – Mendelian randomization – uses genetic variation in a person’s DNA to help understand the causal relationships between risk factors and health outcomes to provide a more accurate estimate of relationships by removing confounding factors (such as smoking, income and physical activity) and reverse causation (where people lose weight due to ill-health), which can explain conflicting findings in previous studies.
Until now, no study has used such a genetic-based approach to explore the link between body mass index and mortality.