Association of betel nut chewing with exercise performance in a military male cohort: the CHIEF study

INTRODUCTION: Betel nut chewing may cause obesity, neurohormonal activation and inflammation, possibly impairing exercise performances. METHODS: We examined the cross-sectional association in 4388 military male adults aged 18-50 years from the cardiorespiratory fitness in armed forces study in Taiwan between 2013 and 2014. The status of betel nut chewing was classified as current and former/never based on each participant's response to a questionnaire. Physical fitness was evaluated by three basic exercise tests including 3000 m running, 2 min sit-ups and 2 min push-ups. Multiple logistic regression for the best 10% and the worst 10% performers in each exercise, and linear regression were used to determine the relationship. RESULTS: There were 564 current chewers and 3824 non-current chewers for the analysis. The linear regression shows that current betel nut chewing was positively correlated with 3000 m running duration (r=0.37, p=0.042) after adjusting for age, service specialty, body mass index, exercise frequency and alcohol intake. In addition, the logistic regression shows that as compared with non-current chewers, current chewers had lower odds of being the top 10% performers in 2 min push-ups and higher odds of being the bottom 10% performers in 2 min sit-ups (ORs and 95% CIs: 0.71 (0.50 to 0.99) and 1.32 (1.00 to 1.75), respectively). However, the associations between betel nut chewing and physical fitness were all insignificant after further adjusting for current smoking. CONCLUSIONS: Our findings suggest that the impairment of physical fitness associated with betel nut chewing of military young men might be mainly mediated or moderated by the coexisted cigarette smoking.