welcome to HealthcareMagic
Since your age is 68 and teeth removed and you wear dentures its fine.Now the fatigue
you have cough
and loss of weight these are symptoms seen in case of Tuberculosis
also. So any cough more than 2 weeks needs investigation.As your blood test
you can take iron but i would say you should get a X-ray of chest done to find if there is any problem in chest.If that is normal may be the cough is allergic and if there is any problem in X-ray then consult a doctor and get treated properly.