Type 2 diabetes, sleep apnea showed greatest risk reductions
The researchers looked at the risk reduction for various comorbidities after weight loss, compared with before weight loss. They also examined the risk reductions after weight loss, compared with someone who had always had a median 13% lower weight.
Effectively, the analysis provided a measure of the effect of risk reduction because of weight loss, compared with having that lower weight as a stable weight.
“The analysis asks if the person’s risk was reversed by the weight loss to the risk associated with that of the lower weight level,” explained Dr. Haase.
“We found that the risks of type 2 diabetes, dyslipidemia, and hypertension were reversed while the risk of sleep apnea and hip/knee osteoarthritis showed some residual risk,” she added.
With sleep apnea there was a risk reduction of up to 27%, compared with before weight loss.
“This is a condition that can’t be easily reversed except with mechanical sleeping devices and it is underrecognized and causes a lot of distress. There’s actually a link between sleep apnea, diabetes, and hypertension in a two-way connection,” noted Dr. Finer, who is also honorary professor of cardiovascular medicine at University College London.
“A reduction of this proportion is impressive,” he stressed.
Dyslipidemia, hypertension, and type 2 diabetes are well-known cardiovascular risk factors. “We did not see any impact on myocardial infarction,” which “might be due to length of follow-up,” noted Dr. Haase.
Response of type 2 diabetes to weight loss
Most patients in the study did not have type 2 diabetes at baseline, and Dr. Finer commented on how weight loss might affect type 2 diabetes risk.
“The complications of obesity resolve with weight loss at different speeds,” he said.
“Type 2 diabetes is very sensitive to weight loss and improvements are obvious in weeks to months.”
In contrast, reductions in risk of obstructive sleep apnea “take longer and might depend on the amount of weight lost.” And with osteoarthritis, “It’s hard to show improvement with weight loss because irreparable damage has [already] been done,” he explained.
The degree of improvement in diabetes because of weight loss is partly dependent on how long the person has had diabetes, Dr. Finer further explained. “If someone has less excess weight then the diabetes might have had a shorter duration and therefore response might be greater.”
Lucy Chambers, PhD, head of research communications at Diabetes UK, said: “We’ve known for a long time that carrying extra weight can increase your risk of developing type 2 diabetes, and this new study adds to the extensive body of evidence showing that losing some of this weight is associated with reduced risk.”
She acknowledged, however, that losing weight is difficult and that support is important: “We need government to urgently review provision of weight management services and take action to address the barriers to accessing them.”
Dr. Finer and Dr. Haase are both employees of Novo Nordisk. Dr. Le Roux reported no relevant financial relationships.
A version of this article originally appeared on Medscape.com.