A flattened diaphragm is not a cause of COPD -- no to that ..
It is typically a sign of COPD
A person with good health but a very good full deep breath might be indicative of flattening of the diaphragm so this by itself is not entirely specific ...
Have you a history of smoking ?
Do you have shortness of breath ? Cough ? Wheezing ?
These would be more significant symptoms ...
You may if there is concern of COPD have testing done >> spirometry to tell the details of your pulmonary function
I hope that this information is helpful for you
Let me know if you have further questions or concerns
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Thank you and Best Regards,
Anthony Bray MD