[Effects of smoking on the thyroid gland, digestive system, kidney and bone]

International audience; INTRODUCTION: In addition to being a major cardiovascular risk factor, smoking promotes or worsens thyroid, digestive, renal and bone diseases. BACKGROUND: Smoking is positively associated with hyperthyroidism. It is associated with Graves' disease and it especially increases the risk of the development of severe exophthalmos. In contrast, smoking might exert a protective action for thyroid carcinoma. Smoking increases the severity of hepatic lesions in patients with chronic hepatitis C. Smoking accelerates the progression of primary biliary cirrhosis and increases the risk of hepatocellular carcinoma. Smoking increases risk of both hyperplastic and adenomatous polyps. While Crohn's disease is associated with smoking, ulcerative colitis is largely a disease of non smokers. Smoking increases risk of development of both renal cell carcinoma and chronic nephropathies, particularly in types 1 and 2 diabetes. Smoking is a risk factor for decreased bone density and is associated with a significantly increased risk of fracture. Smoking is related to the development of rheumatoid arthritis and may adversely influence its severity. CONCLUSIONS: Smoking might be considered a risk factor for the development of several thyroid, digestive, renal and bone diseases. Consequently, smoking prevention and cessation programs must be strongly encouraged among the patients concerned.