Obesity is likely to cause an increased risk of kidney disease, according to a study. Chronic kidney disease affects more than 10 per cent of adults worldwide and is predicted to become a global threat to public health.

The findings of study, published in Cardiovascular Research, suggest that tackling obesity could have a powerful impact on kidney health. Researchers from the UK's University of Manchester were able to show that the causal effect of obesity on the kidney is only partly mediated by high blood pressure and Type 2 diabetes. Through analysis of 467 kidney tissue samples, the study also uncovered the signatures of obesity on the human kidney - groups of genes and pathways that may potentially explain the effects of obesity on the kidney.

"Through the analysis of one of the largest collections of the human kidney samples, we have uncovered the specific renal pathways associated with body mass index/waist circumference -- they are the most likely biological connections between obesity and kidney health and disease," said principal investigator Professor Maciej Tomaszewski from the varsity.

Using data from around 300,000 participants, the team extracted information on the two most common measures of obesity, body mass index (BMI) and waist circumference (WC), and different measures of kidney function.

Most of the previous studies have been unable to explain if the relationship between obesity and renal disease was little more than an association. However, through a technique called Mendelian Randomisation -- which groups people according to a genetic code randomly assigned at birth and removes any bias --, they found that increasing values of genetically predicted BMI and WC were causally associated with the measures of kidney function.

"Obesity and kidney disease are common to complex disorders with an increasing clinical and economic impact on healthcare around the globe," said first author Dr Xiaoguang Xu from the varsity. "Our evidence substantiates the value of weight loss as a strategy of preventing or reversing a decline in kidney health, as well as decreasing the risk of renal disease.

"So, we hope our findings will help to stimulate further research and drive the development of public health policies to improve kidney health and prevent kidney disease through encouraging weight loss," Xu said.