Does being overweight increase the risk of severe kidney disease?
9 March 2017
Big data Cardiovascular & metabolic
More than 3 million people in the UK are affected by kidney disease, yet 1 million are unaware they have the condition – which is a staggering statistic when you consider that kidney disease can’t be reversed.
There are a number of causes of kidney disease, with the biggest risk being from uncontrolled diabetes or high blood pressure - particularly in those who are obese.
Today is World Kidney Day, and to highlight the importance of kidney health and our own ongoing clinical research studies on chronic kidney disease (CKD) such as BARACK-D and OxREN, staff and students in the Nuffield Department of Primary Care Health Sciences have marked the campaign by organising a raffle, led by those managing our kidney studies. Cake and sweet treats also made an appearance at today’s event.
While it’s a well-known fact in our department that cake brings our people together, we’re all mindful of the link between obesity and kidney disease (the theme for this year's World Kidney Day), yet there’s some uncertainty in the scientific community about the level of that association. To what extent is being overweight, but not obese, associated with advanced CKD, and how does this differ among different types of people?
To investigate this further, a team of our researchers led by Dr Margaret Smith in this department, Dr William Herrington in the Nuffield Department of Population Health and colleagues in the George Institute for Global Health, have collaborated on a study looking at the BMI measures of 1.4 million adults over seven years using existing data from clinical records.
Published today in PLOS ONE, the study provides direct evidence that being overweight increases the risk of advanced CKD, and being obese substantially increases that risk. This remains true for those with and without diabetes, hypertension or cardiovascular disease.
The researchers found that almost 1-in-100 (0.8%) people developed advanced CKD during the seven years of the study, and 1-in-1000 (0.1%) required dialysis or a kidney transplant. The incidence of CKD was much more common in those who were older, rising steeply from the age of 60, and overall men were at a higher risk of developing advanced CKD than women.
Overall, the study found that in cases of advanced CKD in people between the ages of 40 and 79, 1-in-3 were linked with being overweight or obese. Compared to adults with a healthy weight, those who were overweight, but not obese, were at a 40% increased risk of developing advanced CKD, the risk doubled for those with obesity and tripled for those with severe obesity.
It’s important to note that the majority of people in the study were overweight or obese - 71% of men and 57% of women in the study had a BMI measure of 25 or greater, and the data suggests that men, current smokers and those living in socially deprived areas were more likely to develop advanced CKD compared with women, non-smokers and those from areas with low social deprivation.
To tackle this issue, the researchers suggest placing an emphasis on weight-loss strategies for those who are overweight, as well as those who are obese, to help people reach and maintain a healthy weight and reduce their risk of developing advanced CKD.
Now I don't want to set the cat amongst the pigeons here - there's no doubt we are all going to continue to enjoy the occasional piece of cake, but the evidence for a link between being overweight and advanced CKD is now becoming clearer.
The research is published in PLOS One: Body-mass index and risk of advanced chronic kidney disease: Prospective analyses from a primary care cohort of 1.4 million adults in England. Herrington WG et al, PLOS One 2017 http://dx.doi.org/10.1371/journal.pone.0173515