The picture you sent of the nails is early clubbing. This sign is an unreliable sign for a definite or a single diagnosis. So a conclusion cannot be drown on just this basis. Clubbing can occur in tens of reasons like:
1) Ulcerative colitis (intestinal disease)
2) Pachydermatoperiostosis (skin disease).
3) Interstitial lung disease.
4) Primary biliary cirrhosis,
5) Cirrhosis of the liver
6) Thyroid diseases.
So nail changes are not reliable or conclusive signs. In the absence of symptoms, I would not be worried despite the nail changes. Though with your long smoking history just for caution, you may get the following investigations for the screening;
a) Chest x-ray.
b) Lung function test.
These are just for the evaluation.
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.
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