Effects of Sex, Smoking, and Physical Activity on Metabolic Syndrome Among Current Smokers: A Cross-Sectional Study from Taiwan

<b>Background</b>: Metabolic syndrome (MetS) is a growing global health concern. Although sex, smoking, and physical activity are recognized risk factors, their combined effects remain insufficiently studied, particularly among Asian populations. This study aimed to examine the associations of sex, cumulative smoking exposure, and physical activity with MetS among current smokers in Taiwan. <b>Methods</b>: Data were drawn from 15,385 participants recruited between 2013 and 2017 from a health screening center. Demographic characteristics, smoking status, physical activity levels, and biochemical data were analyzed. Mann-Whitney U tests, chi-square tests, and multiple logistic regression were used to identify variables associated with MetS. <b>Results</b>: MetS prevalence differed significantly by sex, with rates of 13.6% in men and 5.1% in women. Women had a lower chance of developing MetS compared to men (OR = 0.607, 95% CI 0.488-0.754). Older age, higher body mass index, and greater cumulative smoking exposure (quantified using a composite 'smoke area' index derived from questionnaire data on smoking duration, frequency, and daily amount) were positively associated with MetS risk. Among smokers younger than 45 years, women also had significantly lower odds of MetS than men (OR = 0.590, 95% CI 0.451-0.771). Higher levels of physical activity were linked to reduced MetS risk in both sexes. <b>Conclusions</b>: Among current smokers, being female was inversely associated with the risk of MetS. Greater physical activity and lower smoking exposure were also associated with reduced risk. Future research should use longitudinal designs and comorbidities to clarify mechanisms and inform tailored prevention strategies.