Challenges and implications for biomedical research and intervention studies in older populations: insights from the ELDERMET study.

Older people constitute a growing proportion of the worldwide population. Despite this, older people are often excluded from clinical research and are generally underrepresented in intervention studies. This severely restricts the ability to generalise outcomes from research involving younger populations, which may impact on the progression of knowledge and the development of best practice guidelines for the care of older people. This opinion piece outlines the challenges and practical difficulties experienced and overcome by the ELDERMET project. The ELDERMET project has recruited almost 500 subjects, aged 65 years and older, across a range of health states from the very frail to the very fit, half of whom have been studied at multiple time points. All ELDERMET subjects have participated in an extensive protocol and supplied multiple biological sample types. The challenges and obstacles faced by both researchers in recruiting older subjects and older people engaging with research and intervention studies are set out. Strategies are discussed for: the recruitment and retention of older subjects; recruiting subjects with physical or cognitive impairment; recruitment from specific locations; collecting accurate and robust data, particularly from subjects with mild to severe cognitive impairment; intervention product design, delivery and compliance. Practical and realistic solutions for maximising the engagement of older people with research and intervention studies are offered. The increased benefit brought by the generalisation and application of research and intervention outcomes to older populations is discussed.