In which of the following conditions smoking is protective?
Ans. (a) Ulcerative colitisRef : Harrison 19th ed. /1952-53EPIDEMIOLOGY OF IBP Ulcerative colitisCrohn's diseaseMale/female ratio* 1:1* 1.1-1.8.1Smoking* May prevent disease* May cause diseaseOral contraceptives* No increased risk* Odds ratio 1.4Appendectomy* Protective* Not protectiveMonozygotic twins* 6% concordance* 58% concordanceDizygotic twins* 0% concordance* 4% concordance
Ulcerative colitis
Crohn's disease
SLE
Alzheimer's
G.I.T.