Editorial: Nutrients and bioactive compounds: preventing and treating neurodegenerative diseases and disorders.

The need for joined-up thinking in the care of people living with multiple long-term conditions (MLTCs) is widely recognised, with calls to redesign multi-condition healthcare services and shift their focus from single to multiple diseases. Further, such services need to integrate the care of physical and mental illnesses because people with MLTCs are more than twice as likely to experience mental health problems, and this risk is consistently associated with worse outcomes. Baird , among others, argue for a whole-systems approach to move beyond disease-specific care models. International examples including Staten Island and the Netherlands, along with the neighbourhood health model described in the NHS 10-year health plan, demonstrate the potential of holistic, community-based strategies for person-centred services. By bringing together the needs of multiple stakeholders, systems engineering provides an inclusive and holistic approach to the design of complex systems such as MLTC care pathways. The aim of this study was to use systems engineering principles to identify barriers and improvement opportunities for the effective management of care for people with MLTCs and consequently propose a service system architecture to enable such care to be provided with equality and equity. MLTC service systems are typical of the most complex kind of system in that they both impact and are impacted by multiple clinical disciplines and specialties, and economic, social and environmental factors. The design of new MLTC service systems can, therefore, be seen as a ʻwicked problem’: no individual can fully understand the whole problem (Finitude); it is difficult to link actions to consequences because the problem and potential solutions are highly interconnected (Complexity); and the behaviour of the system is governed by human and organisational behaviours that influence the feasibility and effectiveness of solutions (Normativity). A consequence, especially in safety-critical systems such as health and social care, is that innovations are most likely to succeed if introduced incrementally. This provided the underlying rationale for the methods used.