Synergistic effects of physical and psychological stress upon immunosenescence
For the majority of older people in the UK old age is a positive experience in health terms. However for many, good health can be lost rapidly resulting in poor physical or mental health. Falls represent a major cause of ill health and loss of independence in older people. Furthermore, mortality associated with hip-fracture, a frequent consequence of falls, is very high, with 1 in 5 patients dying within a year of their hip-fracture.
A major reason for poor health after hip-fracture is increased susceptibility to infections, particularly pneumonia. This study will investigate another common feature of hip-fracture patients, depression, to try and understand why some older people suffer poorer health than others after a hip fracture. Depression is present in almost one third of hip-fracture patients and is also associated with suppression of the immune system. In this study we will determine if depression compounds the negative effects of hip-fracture upon the immune system and may explain why some older people have poorer health after hip fracture. Our study will also consider whether there are ethnic differences in attitudes towards hip-fracture and if these can affect how a minority ethnic grouping (British Punjabi Indians) recover from hip-fracture.
Janet Lord, Birmingham University
Partners and Collaborators:
For many seniors the conversion from being a healthy older adult to one in frail physical or mental health can be sudden, with falls representing a key cause of increased morbidity and mortality. Almost 1 in 3 people over 65 will fall at least once a year. Hip fracture is a frequent consequence of a fall and is a catastrophic event that happens to approximately 86,000 older people in the UK each year. Fracture is associated with poor outcome, approximately one third of patients are dead at one year post fracture and one quarter enter institutionalisation at discharge. Few regain pre-fall levels of quality of life.
It is well established that our immune system declines with age and post-operative chest infections are the major 6 month mortality risk factor in hip-frature patients, with pneumonia the cause of death in 43% of patients. Physical trauma, such as a fall, is thus a major risk for progression to frailty in seniors and reduced immunity is a key underlying frailty factor. If we are to improve quality of life for older people, understanding how falls and hip fractures can lead to frailty and how we might intervene to maintain health after hip fracture, is imperative.
Depression is also associated with increased susceptibility to infectious disease, with reduced immune cell function. Furthermore, depression is in 30 % of hip fracture patients and symptoms of depression in patients with hip fracture hold considerable implications for prognosis. Depression has been associated with greater pain persistence, retarded recovery and higher mortality rates. Depression coincident with the physical trauma of hip fracture may therefore accelerate progression from health to frailty via a negative impact upon immunity.
A key question that remains to be addressed, and which has great significance for the health and quality of life of seniors after falls and hip fracture, is therefore whether depression and physical trauma synergise to accelerate ageing of the immune system.
Finally, there is an important and often neglected additional factor that can influence how quickly and how well an older person recovers from illness, namely the beliefs and meanings (i.e. the illness representations) he/she attaches to the illness. There is evidence that minority cultural groups hold illness representations that differ in various respects from the majority in the UK. Studies of the perception of age-associated dementia amongst British people of Punjabi Indian origin has revealed that symptoms of dementia were thought to partly result from a lack of effort by the patient themselves. Extending such studies to consider attitudes to hip fracture will address this issue in a significant minority ethnic patient grouping in the UK.
The overall aim of this study is to determine whether ageing, physical stress (hip fracture) and psychological stress (depression) are key and interacting factors influencing immune frailty in seniors. It is also important to determine whether the negative cumulative effects of these stressors extend beyond immune frailty and lead to cognitive and physical frailty. The study will additionally determine whether or not illness representations affect quality of life for hip fracture patients in a minority ethnic group.
The study has a three year prospective case-control design with four groups of female seniors: 50 British white hip fracture patients with, or without depression; 30 British patients of Punjabi Indian ethnicity with hip fracture but no depression and 50 healthy seniors. Patients will be assessed one and six months after hip fracture to determine the short and long term effects of the trauma.
To assess the combined impact of hip fracture and depression immunity: We will assess innate immune function and the immune risk phenotype in older adults with or without hip-fracture and with or without depression.
Examine the role of hormones: We will measure levels of stress hormones (cortisol; DHEAS) to determine their role in mediating the negative effects of depression and hip fracture upon immunity and wider aspects of frailty.
Examine the link between immune frailty and physical and mental frailty: A stress may also affect other aspects of frailty such as physical and mental frailty and these will be assessed at 6 months post-fracture.
Determine whether illness representations differ between hip fracture patients of British white and Punjabi Indian ethnicity: If minority ethnic groups hold different illness representations for hip-fracture this may affect their recovery from illness and this will therefore be determined in a pilot study as part of the overall project.
This project will have a range of policy impacts, mainly in the area of rehabilitation practices for hip-fracture patients.
1. Key policy and/or practice implications of the research
Policy and practice implications will focus primarily on considering whether interventions to reduce depression in hip-fracture patients will improve prognosis, specifically whether this could lead to a reduction in life-threatening infections in the months following the fracture. These are likely to include:
The project will also potentially have impact upon rehabilitation practices of ethnic minority patients if differences in illness representations are found in the British Punjabi group of patients. A follow up study would however be required to determine if the illness representations of this group had a positive or negative impact upon their recovery from hip-fracture.
2. Key non-academic user groups that will be targeted