Introduction: there is a lack of longitudinal studies investigating daily tobacco use and problem drinking in Africa. The aim of this study was to explore the prevalence of daily tobacco use and problem drinking and to determine the factors associated with daily tobacco use and problem drinking among urban dwellers in a longitudinal study in South Africa.

Methods: electronic interview data were collected from 2213 adults (mean age 45.7 years, SD=15.1; range 20-97) at time 1 (baseline assessment) and Time 2 (12 months follow-up assessment) from one urban centre in South Africa.

Results: daily tobacco use only, was at time 1 24.0% and at time 2 23.4%, a decrease of 0.5%. Problem drinking only was at time 1 19.6% and at time 2 21.1%, an increase of 1.5%. Concurrent daily tobacco use and problem drinking increased from time 1 9.5% to 10.3% at time 2, an increase of 0.8%. In longitudinal regression analyses, being male and being born in current city were significantly associated with all three substance use indicators (daily tobacco use; problem drinking; and concurrent daily tobacco use and problem drinking). In addition, older age, not currently married, lower education, underweight and higher levels of perceived stress were associated with daily tobacco use and younger age was associated with problem drinking.

Conclusion: high prevalence of daily tobacco use and problem drinking were found among urban dwellers and several socio-demographic (being male, being born in the city, not married and lower education) and health variables (being underweight and perceived stress) were identified which can guide substance use intervention programmes for this population.