Tobacco smoking in Tanzania, East Africa: population based smoking prevalence using expired alveolar carbon monoxide as a validation tool

Objectives: To describe the prevalence of tobacco smoking in an urban East African population while using a simple validation procedure to examine the degree of under reporting in men and women. Design: A cross sectional population based study in adults (15 years and over) with sampling from a well maintained census register. Setting: Ilala Ilala, a middle income district of Dar es Salaam, Tanzania. Subjects: An age and sex stratified random sample of 973 men and women. Main outcome measures: Self reported smoking status with correction by exhaled alveolar carbon monoxide (EACO). Results: From the 605 participants (response rate 67.9%) age standardised (new world population) smoking prevalence, based on questionnaire and EACO, was 27.0% (95% confidence interval (0) 20.8% to 33.2%) in males and 5.0% (95% Cl 2.8% to 7.2%) in females. The age specific prevalence of smoking was highest in the age group 35-54 years (34.3%) for men and in the over 54 years group (16%) for women. Of those classified as smokers, 7.3% of men and 27.3% of women were reclassified as current smokers based on EACO (greater than or equal to 9 parts per million), after they had reported themselves to be an ex- or non-smoker in the questionnaire. Conclusions: The data suggest: (1) high rates of smoking among men in an urban area of East Africa; and (2) the importance of validating self reports of smoking status, particularly among women.