4947Association between secondhand smoke exposure and diabetes mellitus in 131,724 Korean never smokers using self-reported questionnaire and cotinine: gender differences

Abstract

Abstract Background No study has reported the relationship between secondhand smoke (SHS) exposure and diabetes mellitus in self-reported never-smokers verified by nicotine metabolite. Purpose The aim of this study is to determine the relationship between SHS exposure and diabetes mellitus in self-reported and cotinine-verified never-smokers. Methods A total of 131,724 self-reported and cotinine-verified never-smokers (42,681 men; age 35.0±7.1 years) enrolled in Kangbuk Samsung Health Study (KSHS) and Kangbuk Samsung Cohort study (KSCS) between 2011 and 2016 were included. Cotinine-verified never-smoker was defined as individuals having urinary cotinine <50 ng/mL. SHS exposure was defined as having experienced passive smoking indoors at home or the workplace. Diabetes mellitus was defined as having a fasting blood glucose level of ≥7.0mmol/L, hemoglobin A1C ≥6.5% or taking anti-diabetic medication(s). Results The frequency of diabetes mellitus in the overall population was 1.6%; the frequency in males was higher than that in females (2.2% versus 1.3%, p<0.001). The overall frequency of SHS exposure was 22.9%, with rates of 27.6% for males and 20.7% for females (p<0.001). The frequency of diabetes mellitus in group with SHS exposure was higher than that in group without SHS exposure only in females (1.8% versus 1.2%, p<0.001 for females; 2.2% versus 2.2%, p=0.956 for males). There was significant gender interaction for the relationships between SHS exposure and diabetes mellitus (p for interaction <0.001). A multivariate regression model was adjusted for the baseline variables including age, waist circumference, body mass index, frequency of alcohol drinking and vigorous exercise, systolic blood pressure, blood urea nitrogen, creatinine, uric acid, total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride, and hsCRP. Only in females, SHS exposure was significantly associated with diabetes mellitus (odds ratio [95% confidence interval], 1.40 [1.20, 1.65] for females; 1.00 [0.85, 1.19] for males). Higher frequency and longer duration of SHS exposure were also significantly associated with diabetes mellitus (p<0.001) for all trends). In particular, females with SHS exposure of ≥1 hours/day, ≥3 times/week, and ≥10 years increased the risk of diabetes mellitus 51–64% above that for those without SHS exposure (1.64 [1.25, 2.13], 1.51 [1.21, 1.87], and 1.59 [1.30, 1.95], respectively. Conclusions This study showed that the SHS exposure in females was significantly associated with diabetes mellitus in self-reported never-smokers verified by urinary cotinine and this association was proportional to the frequency and duration of SHS exposure. These findings suggest the importance of banning smoking in the home and public to reduce the risk of diabetes mellitus. Acknowledgement/Funding None