Clustering of NCD Risk Factors Among Adults aged 18 to 69 in Tanzania: Results from the 2023 STEPS Survey

Background: Non-communicable diseases (NCDs) are a leading cause of morbidity and mortality globally, with a rapidly increasing burden in low- and middle-income countries such as Tanzania. The clustering of multiple NCD risk factors within individuals substantially increases the risk of cardiovascular disease, diabetes, and premature mortality, yet national evidence on risk factor clustering remains limited. Methods: This study analysed data from the nationally representative Tanzania WHO STEP-wise Survey conducted between September and November 2023. A total of 3,369 adults aged 18–69 years were included using a three-stage stratified sampling design. Five NCD risk factors were assessed: current daily smoking, inadequate fruit and vegetable intake, insufficient physical activity, overweight or obesity, and hypertension. Clustering was defined as the presence of three or more concurrent risk factors. Weighted analyses and modified Poisson regression models were used to identify associated factors. Results: Overall, 15.5% (95% CI: 13.2–18.1) of adults had three or more NCD risk factors. The prevalence increased sharply with age, from 5.6% among adults aged 18–30 years to 24.6% among those aged 46–69 years. Urban residents had a significantly higher prevalence than rural residents (18.9% vs. 12.6%). Significant geographic variation was observed, with the highest prevalence in the Southern zone (33.0%) and elevated risk in Unguja and Southern Highlands. In adjusted analyses, older age, urban residence, and geographic zone were independently associated with risk factor clustering. Conclusion: Clustering of NCD risk factors is common among Tanzanian adults, particularly among older and urban populations, underscoring the need for integrated and targeted NCD prevention strategies.