Correlation between cotinine urinary levels & cardiovascular autonomic function tests among smokeless tobacco chewers: A cross-sectional study

BACKGROUND & OBJECTIVES: Cardiovascular disease (CVD), the leading cause of death worldwide is responsible for over 17 million deaths globally, of which 10 per cent deaths have been expected due to consumption of tobacco. The association between CVD and chewing of tobacco is limited and remains arguable. The aim of this study was to find out the correlation between urinary cotinine level and cardiovascular autonomic function tests of tobacco chewers. METHODS: In the present study, 600 participants, 300 smokeless tobacco chewers (STC) and 300 non-tobacco chewers (NTC), between 18 and 65 yr were selected. Various parameters such as anthropometric, systolic blood pressure (SBP), diastolic blood pressure (DBP), autonomic function tests and urinary cotinine levels were measured. RESULTS: Significant difference (P<0.001) was noted in STC and NTC for anthropometric parameters, SBP, DBP and urinary cotinine levels. Sympathetic and parasympathetic autonomic function test showed significant difference on comparison in STC and NTC groups, except in Valsalva ratio. Correlations with urinary cotinine levels were significant for sympathetic autonomic functions, SBP fall (r=0.138, P=0.016), DBP rise (r=−0.141, P≤0.014); parasympathetic autonomic function, heart rate (HR) response to standing (r=−0.208, P≤0.003), deep breathing (r=−0.473, P≤0.001) and Valsalva ratio (r=−0.396, P≤0.0001). INTERPRETATION & CONCLUSIONS: Correlation between urinary cotinine levels and autonomic function tests elucidates the linkage involving autonomic nervous system damage which can be considered as an important associated relationship for early diagnosis of CVD health risk factors among smokeless tobacco (ST) users.