Chronic Obstructive Pulmonary disease and Diabetes Mellitus are both common and under-diagnosed diseases. COPD is considered as a risk factor for Type 2 Diabetes due to inflammation, oxidative stress, insulin resistance and weight gain. On the other hand Diabetes may act as an independent factor as it negatively impacts upon pulmonary structure and function. It also results in an increased risk of infection and worsened COPD outcomes. Recognising the inter-relations between these two diseases can help to improve the outcome and medical control for both conditions.

Patients with COPD have an increased risk of developing Diabetes. Not only directly but indirectly as COPD patients often suffer from other medical conditions like elevated blood pressure and high cholesterol levels, which are linked to diabetes. The combination of these medical problems is often referred to as ‘metabolic syndrome’.
The specific pathology as to why COPD patients are at a high risk of developing diabetes is unclear, but it is thought that it is due to inflammation associated with lung disease and the use of corticosteroids.
Elevated levels of glucose are associated with abnormal lung function. Those with type 1 diabetes experience a 20% decline in lung function and it may contribute to worsening symptoms in COPD patients.
Diabetes can affect the lungs in different ways. It has been associated with decreased lung volume, reduced lung expiration volumes and reduction in the ability of the lung tissue to diffuse oxygen. It is thought that glucose affects the diaphragm, breathing muscles and nerves in the lungs.
Diabetes is also associated with abnormal brain control of breathing pattern and can cause sleep-breathing disorders. Studies show that COPD patients with diabetes have an accelerated decline in lung function compared to those without diabetes and uncontrolled diabetes in COPD patients result in increased exacerbations, more frequent and longer hospitals stays and risk of death.
The adverse affects of diabetes on lung function appears to be stronger among people who smoke tobacco, and this group of people also have the highest risk of developing COPD.
Both conditions have also been linked to a phenomenon called oxidative stress, in which highly energized compounds called reactive oxygen species, which react strongly with other molecules, damage tissue. In the case of COPD, oxidative stress injures the airway and promotes inflammation in the lungs, and oxidative stress has been implicated as an underlying cause of the insulin resistance seen in Type 2 diabetes.
Both conditions can occur independently of each other but can also occur due to the presence of the other one. Both diseases also have a negative impact upon the state of the other. COPD will cause worsening of Diabetes and vice-versa. Therefore adequate diabetic control is key for patients with COPD to prevent worsening of their condition, as there is no cure for COPD and prevention is critical.
Due to the huge overlap between these conditions if you have been diagnosed with either condition you should ask your GP to check for the other. If you have diabetes and have a history of smoking you are at a high risk for developing COPD and like-wise if you have COPD make sure you are checked for diabetes especially if you have a family history of diabetes.

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