Rapid weight loss in older people is defined as the involuntary decline in total body weight by >5% over a six to 12-month period. This magnitude of weight loss has been suggested by some to be an indicator of health status, and unintentional weight loss occurs in up to one in four community-dwelling frail older adults.
The pathophysiology of rapid weight loss remains poorly understood, However, when it occurs it can be detrimental and shown to be associated with poorer health outcomes including an increased risk of falls, fractures, mortality, institutionalisation, cognitive decline, Alzheimer’s disease, and declines in physical function and quality of life. Traditional management of maintaining weight of the older adult usually incorporates a lifestyle approach (e.g. exercise and healthy diet including adequate protein intake).
Vascular health is essential for the absorption of nutrients at the gut and a nexus between compromised vascular blood supply and suboptimal nutrient absorption may exist.
Abdominal aortic calcification (AAC) is a process involving mineral deposition in the arterial wall, which represents an early site of vascular calcification, and is a strong predictor of cardiovascular disease (CVD) risk.
AAC is related to musculoskeletal health that is a risk factor of rapid weight loss. For instance older women who had extensive AAC presented with a greater decline in hand grip strength, and older men had higher risk of AAC progression if they had low muscle mass and poorer physical function. AAC in older women is also shown to be related to late-life dementia, as well as increased falls and fractures risk.
AAC is a marker of multi-site atherosclerosis, related to atherosclerosis and stenosis of other vascular beds (e.g. superior mesenteric arteries), and is related to all-cause mortality. Extent of AAC is also related to the health of other organs such as common bile duct diameter (important for nutrient absorption), suggesting generalised atherosclerosis may affect intra-abdominal organs.
Given that the risk of atherosclerosis of the gastrointestinal tract (coeliac, superior mesenteric and inferior mesenteric arteries) increases with increasing age and can result in post-prandial abdominal pain and weight loss, we hypothesised in our study that AAC, a potential marker of generalised ischemic gastrointestinal artery disease, is related to rapid weight loss in 929 community dwelling older women (mean ± SD age 75.0 ± 2.6 years).
Key findings of the published work
During five-years of observation, two in five women had rapid weight loss, which was associated with a 49% increase in all-cause mortality in the next 9.5 years. This risk increased to 87% higher in women who experienced rapid weight loss of more than 10% in a 12-month interval. In the one in two women with moderate to extensive AAC, they had 36% and 58% higher odds of having rapid weight loss over the next five years.
These results remained similar after adjusting for dietary factors and cardiovascular risk factors such as blood pressure and cholesterol. Importantly, this link was still seen in women meeting protein and energy and physical activity recommendations. This suggests new interventions to attenuate unexplained weight loss in older people may be required for those with vascular disease.
A limitation of the work is that the mechanisms underlying the relationship between AAC and rapid weight loss remain unclear.
One hypothesis is that AAC could be limiting blood flow to the gut, which in turn could be affecting the absorption of nutrients. This has the potential to change how we treat those older individuals who present with rapid weight loss. The traditional approach would be to increase protein and energy intake, but data suggests that vascular disease may be driving or a contributor to weight loss, in which case using the traditional approaches may not help with body composition.
Given the poor outcomes commonly associated with rapid weight loss in older adults, AAC may be a tool to identify those older women with highest risk.
Key messages
- Results from this study suggests that vascular disease may increase the risk of rapid weight loss in older women
- A causal mechanism has not been determined
- Better understanding of this link may open the door to new treatments targeting vascular disease.
– References available on request
Author competing interests – ECU has lodged a patent for automated assessment of abdominal aortic calcification. Associate Professor Joshua Lewis is a named inventor on this patent. The salary of Associate Professor Joshua Lewis and accredited exercise physiologist Dr Cassandra Smith is supported by Heart Foundation Fellowships.