Lung cancer in Northern India in relation to age, sex and smoking habits.

Primary lung cancer in Northern India was analysed in relation to age, sex and smoking history in 480 histologically diagnosed cases. The M:F ratio rose progressively up to the 51-60 years age group and was about the same thereafter. The M:F ratio was very high in smokers and was almost identical for all cell types (greater than 20:1). In non-smokers, the M:F ratio differed with the cell type. The smoker:non-smoker ratio differed significantly in the age groups below and above 40. In those up to 40 years of age, the predominant cell type was small cell carcinoma and the cell type had no significant association with smoking habit. Above 40 years of age, the squamous cell type was most common in smokers and adenocarcinoma in non-smokers.