Individuals who carry excess weight around their stomachs rather than their hips – commonly referred to as being “apple-shaped” – are more likely to have kidney disease, regardless of BMI, Medical News Today reported.
According to a new study from the Netherlands, apple-shaped people not only have poorer kidney function than their pear-shaped counterparts, but they also have lower blood flow and higher blood pressure in the kidneys.
Carrying excess fat around the mid-section has long been associated with poor kidney function, but scientists have not fully understood the underlying mechanisms of the link.
Arjan Kwakernaak, lead author of the study, and colleagues at the University Medical Center Groningen focused on an individual’s waist-to-hip ratio (WHR), which ultimately measures the amount of body fat carried around the mid-section. They analyzed the WHRs of 315 healthy individuals with an average body mass index (BMI) of 24.9 kg/m2 – in relation to their kidney health. A normal weight BMI is anywhere between 18.5 and 24.9 kg/m2.
Ultimately, those with higher WHRs had lower glomerular filtration rates (GFR) – the volume of fluid the kidneys are capable of filtering during a given period of time. The relationship held true even for apple-shaped people, even though they were completely healthy and had normal BMIs.
"WHR was associated with lower GFR, lower effective renal plasma flow, and higher filtration fraction, even after adjustment for sex, age, mean arterial pressure, and BMI," the authors wrote.
The findings were published online in the Journal of the American Society of Nephrology (JASN).