The research was conducted by two independent groups of scientists at the University of California and the Thomas Jefferson University in Philadelphia.
People who are obese have up to a seven times greater risk of developing kidney failure than normal weight people, according to the University of California researchers, who suggest that obesity should be considered a risk factor for the disease.
The study, which also reveals that being "even moderately overweight" nearly doubles the risk of developing the condition, was published in the January 3 issue of the Annals of Internal Medicine.
The findings were based on data collected from over 320,000 people who were followed up for a period of 26 years. Kidney failure, or end-stage renal disease, is currently one of the top ten leading causes of death in the US and affects more than 400,000 Americans, a figure estimated to increase to 650,000 in the next five years.
The condition occurs when the kidneys are no longer able to process waste, leading to the need for dialysis or transplantation. One of the ways in which obesity may contribute to the condition is by placing more metabolic demand on the kidneys, forcing them to work harder, said the scientists.
"As the person gets bigger, hyper-filtration occurs, and this over filtration is what tears the kidneys down," said lead author Chi-yuan Hsu.
And people who are obese also run a higher risk of developing diabetes, a traditional risk factor for end-stage renal disease.
Further research conducted by scientists at Thomas Jefferson University in Philadelphia together with colleagues from Edith Cowan University in Joondalup, Western Australia, also establishes a "strong correlation" between obesity and Alzheimer's disease.
Their study, published in last month's issue of the Journal of Alzheimer's disease, finds that the fatter a person, the higher their blood levels of beta-amyloid, a sticky protein substance that builds up in the Alzheimer's brain.
According to the researchers, beta-amyloid is thought to play a major role in destroying nerve cells and in cognitive and behavioral problems associated with the disease.
"We looked at the levels of beta-amyloid and found a relationship between obesity and circulating amyloid. Heightened levels of amyloid in the blood vessels and the brain indicate the start of the Alzheimer's process," said the scientists in the study.
Evidence has emerged over the last five years that many of the conditions that raise the risk for heart disease, such as obesity, uncontrolled diabetes and hypercholesterolemia, also increase the risk for Alzheimer's, according to Dr Sam Gandy, director of Thomas Jefferson University's Farber Institute for Neurosciences.
However, exactly how such factors contributed to the disease have remained a mystery, he added.
"Ours is one of the first attempts to try to find out on both the pathological and the molecular levels how obesity was increasing the risk of Alzheimer's," he said.
Obesity, which is currently thought to affect more than 64 percent of the US's adult population and 16 percent of children, has already been repeatedly linked with an increased risk of health conditions such as heart disease and diabetes.
And recently, a number of academic studies presented at the AACR International Conference on Frontiers in Cancer Prevention Research revealed growing evidence that overall cancer incidence and mortality resulting from overweight and obesity is also increasing.