Lung Capacity Declines Faster With Diabetes
Finding shows respiratory system suffers collateral damage from blood sugar disease
FRIDAY, March 28, 2008 (HealthDay News) -- Diabetes, the leading cause of heart disease, stroke, blindness, kidney failure and non-traumatic amputations, can also cause the lungs to deteriorate quicker than they normally do with age, a new study shows.
Although everyone experiences a decline in lung function as they grow older, research published in the April issue of Diabetes Care concluded that the lungs of people with type 2 diabetes deteriorate more quickly than normal.
The Johns Hopkins team that conducted the research, part of a larger investigation known as the Atherosclerosis Risk in Communities (ARIC) study, found in previous research that reduced lung function predicted and preceded the development of type 2 diabetes.
In this latest study, there was an average difference of 6 millimeters more decline per year in forced vital capacity (FVC), a measure of how well the lungs fill with air, said study author Hsin-Chieh Jessica Yeh.
The scientists suggest the accelerated reduction in forced vital capacity (FVC) found in people with diabetes could be the result of high blood sugar levels stiffening lung tissue or fatty tissue in the chest and abdomen restricting the lungs.
The ARIC is a prospective cohort study of 15,792 adults from four U.S. communities. The present analysis, which looked at 1,100 diabetics and 10,162 non-diabetics, was based on three years of follow-up.
"This study confirms the results of five previous studies, which demonstrated lower lung function in diabetic subjects compared with their non-diabetic counterparts," said Dr. Guillermo E. Umpierrez, an associate professor of medicine at Emory University and section head of Diabetes and Endocrinology at the Grady Health System, both in Atlanta. "These studies also demonstrated a higher annual rate of lung function decline in the diabetic compared with the non-diabetic population. Although the information is not novel, this report enhances recognition of the lung as a target of diabetic injury."
Most of the diabetic participants in the current study had type 2 diabetes, so the scientists were not able to look at decreases in lung function among type 1 diabetics, who have to use insulin on a daily basis.
"On the other hand, we found diabetes severity, as indicated by intensity of anti-diabetic treatment, was associated with greater rate of FVC decline. Patients on insulin treatment, alone or with oral medications, had the greatest decline in forced vital capacity compared to their non-diabetic counterparts," Yeh explained.
In an accompanying editorial, Dr. Connie Hsia, of the University of Texas Southwestern Medical Center, cautioned that using inhaled insulin might trigger or exacerbate the pulmonary dysfunction found in people with diabetes.
"However, since none of our study participants were on inhaled insulin, our study did not have direct implications on the use or absorption of inhaled insulin," Yeh said.
Umpierrez pointed out that the use of inhaled insulin needs more study. "The future of inhaled insulin for treatment of diabetes is uncertain; however, some pharmaceutical companies continue to investigate the safety and efficacy of inhaled insulin as an alternative of insulin injections," he noted.
Diminished lung capacity may lead to lower oxygen delivery to all body tissues, he noted, although the drop in lung function among diabetics in this study appears to be small. However, in elderly patients with long-standing diabetes, impairment of lung capacity could worsen the risks of adverse outcomes should the elderly diabetic develop pneumonia, heart failure, volume overload or vascular complications, he added.
"Traditionally, the lung is not treated as a target organ for diabetes complication. Based on the current study, we suggest physicians add lung function on the watch list as they care for their diabetes patients," Yeh said.
For more on diabetes, visit the American Diabetes Association.