Body-weight cycling (also known as yo-yo dieting) has been shown to significantly increase the risk of kidney disease in people with type 1 diabetes, regardless of body mass index (BMI) and other traditional risk factors, according to a study published in the Journal of Clinical Endocrinology & Metabolism.

Yo-yo dieting is defined as repeatedly losing and gaining weight multiple times over the years. Its prevalence is reported to be as high as 35% in men and 55% in women.

This pattern of dieting has been shown to increase risks of cardiovascular events in both the general population and in people with type 2 diabetes, and more recently in type 1 diabetes.

This is the first study to show a link between yo-yo dieting and kidney events in people with type 1 diabetes, according to the authors. Type 1 diabetes was long considered a disease of lean individuals. But as with the general population, the prevalence of obesity is rising among those with type 1 diabetes as well, the authors note.

"We showed that high body-weight variability is associated with increased risk of different outcomes of diabetic kidney disease (DKD) progressions in people with type 1 diabetes, independently of traditional DKD risk factors," said lead author Marion Camoin, M.D., of the Center Hospitalier Universitaire de Bordeaux, France. "To our knowledge, this is the first study showing this association."

Researchers from France examined six years of body-weight indices for the 1,432 participants in the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study.

The primary index for identifying yo-yo dieting patterns in the study was known as "variability independent of the mean" (VIM), which measures fluctuations above and below a person's average body weight.

Using the weight fluctuation data, researchers examined six criteria for kidney function decline and progression towards chronic kidney disease. Their primary criteria was the "estimated glomerular filtration rate" (eGFR), which measures how well the kidneys filter toxins from the blood.

Participants with greater weight fluctuations experienced a 40% decline in eGFR from baseline values, according to the study. Those with greater weight fluctuations also were more likely to exhibit moderately and severely increased albuminuria, a condition in which the protein albumin is abnormally present in the urine. Larger amounts occur in the urine of patients with kidney disease.

Similar findings of kidney disease were confirmed by the other examined indices.

Potential risk factors of body-weight cycling

The pathophysiological mechanisms linking body-weight cycling to renal risk are still not fully understood, the authors acknowledge. But they do offer a few hypotheses, including that insulin therapy, which is needed to treat type 1 diabetes, can contribute to body-weight cycling. Other researchers have theorised that body-weight cycling can lead to added strain on the heart and contribute to kidney and vascular damage.

Authors in the current study offer a suggestion to lower the risks of yo-yo dieting and the occurrence of kidney disease:

"Strategies aimed at weight reduction in people with type 1 diabetes should focus on promoting long-term weight maintenance, as weight stability may have a positive impact on health outcomes."

More information: Journal of Clinical Endocrinology & Metabolism