Impact of Smokeless Tobacco on Cardiovascular Disease Risk in a Nigerian Metropolitan City

The use of smokeless tobacco products (STP) as a substitute for tobacco smoking is driving increasing consumption of these products especially in developing countries. The study sought to make comparison of cardiovascular risk profile between chronic STP users and suitably matched tobacco-naïve controls. This is a preliminary report from the cross sectional part of a two-arm prospective study of Smokeless Tobacco Products Composition and Exposure Outcome in Enugu metropolis, Nigeria. Consecutively recruited current Smokeless tobacco users, who had no history of cigarette smoking, aged 18 years and above, residing in selected communities in Enugu metropolis, Nigeria were recruited for the study from October 2022 to July 2023. Age and sex matched non-tobacco users from same localities as the study subjects served as controls. Written informed consent to participate in the study was obtained from all study participants. All participants were screened by the investigators, using the study case report forms, to obtain data on medical history, demographic, clinical, laboratory, and electrocardiographic evaluation. Data from 54 STP-users and 54 non-STP-users (mean age 56.58 ± 8.15 years) were analyzed. Anthropometric parameters were similar in both groups. Smokeless tobacco users had higher erect and supine blood pressure indices as well as greater postural drop in systolic blood pressure. The occurrence of diabetes mellitus (20.37% versus 5.56%) and hypertension (25.93%; 11.11%) was significantly higher in the STP-users than in the non-user population, (p = 0.02192 and 0.04751 respectively). Electrocardiographic evaluation showed significantly increased QTc and dispersions of P-wave, QRS and QT intervals as well as reduced PR interval in STP users. Electrocardiographic abnormalities observed in STP users include left ventricular hypertrophy, left atrial enlargement, ST-segment elevation, short PR interval and long QTc. Use of smokeless tobacco products is associated with increased risk burden of diabetes mellitus and hypertensive heart disease. Electrocardiographic findings linked to STP-use in this study are features consistent with arrhythmia, ventricular repolarization abnormality, myocardial hypertrophy and ischaemia, suggesting that smokeless tobacco products are not safe substitutes for tobacco smoking.