Being overweight in old age is not protective—it is linked to worse health outcomes, including a higher chance of dementia, once smokers and people with weight-loss-inducing illnesses are removed from the data. This matters because a widely publicised "obesity paradox" has led some to believe that carrying extra pounds later in life is harmless or even beneficial. The research, using large UK electronic medical records and volunteer databases, shows that claim is misleading. It stems from biased comparisons and the BMI formula’s failure to account for abdominal fat and age-related muscle loss. Similarly, the apparent benefit of higher blood pressure in older adults may be an illusion caused by blood pressure falling naturally in the 15 years before death. If these findings are adopted, clinical guidelines for older adults could shift. Doctors might stop dismissing weight gain as benign and instead monitor waist circumference alongside BMI. Blood pressure management near the end of life may also need rethinking, though further work is needed. The study found that fewer than 3% of older adults in England have near-ideal cardiovascular risk factors, suggesting enormous room for improvement in healthy ageing outcomes.
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In this project we aimed to improve evidence on cardiovascular risk factors in later life, to help people age well. Some scientists have claimed these heart disease risk factors are not predictive in later life: for example there has been substantial publicity about how being overweight or obese in old age may even be beneficial. We used very large databases of electronic medical records and data from study volunteers, to clarify this evidence. Our main conclusions are: 1) That the claimed obesity risk paradox in later life (i.e. being overweight or obese is associated with equal or better outcomes compared to normal BMI) is deeply misleading. It is true only if smokers and people with diseases causing weight loss are included, but this biases the results. It is also driven in part by mismeasurement due to the BMI formula, which ignores adiposity in the stomach area, and does not account for the muscle loss seen in later life. Overall, for ageing well, it is clear that having a normal BMI and waist circumference is associated with substantially better outcomes compared to older groups with more adiposity. 2) Some have claimed that being obese is not a risk factor for dementia, but on taking account of the biasing factors noted above, we showed that this is not true, and being obese is associated with a substantially increased chance of being diagnosed with dementia. 3) That the reported paradoxical risk estimates from higher blood pressures in later life may be confounded by substantial falls in pressures for approximately 15 years before death. This work is apparently the first report of long term trends in BP toward the end of life. It has potential major implications for BP management toward the end of life but more work is needed to clarify how care should be modified. 4) In groups of 60 to 69 year olds with near ideal cardiovascular risk factors, ageing well outcomes over 10 years are dramatically better than in groups with less ideal risks. This finding counters claims that CVD risk factors are not predictive in later life. The finding also provides an indication of the very large extent to which ageing outcomes could be improved in the older population. Unfortunately less than 3% of the general older population in CPRD (representative of England) had near ideal CVD risks.
NIHR School for Public Health Research - Public Health
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