Prolonged Sitting Time Was Associated With Central Obesity-Related Parameters Among Hong Kong Chinese Women: A Cross-Sectional Study

Introduction: The evidence concerning the association between sitting time and central obesity in Hong Kong Chinese women was still scarce.

Hypothesis: Prolonged sitting time was positively associated with increased waist circumference (WC), hip circumference, and trunk body fat percentage; and also larger waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) among Hong Kong Chinese women.

Methods: Data were extracted from a cohort study named “Migraine Exposures and Cardiovascular Health in Hong Kong Chinese Women”. The baseline data (2019-2021) were used for analysis. Sitting time and physical activity level were measured by the International Physical Activity Questionnaire short form. Body weight, height, WC, hip circumference, and trunk body fat percentage were measured according to standard protocol. The WHR and WHtR were then calculated. Central obesity was defined as WC ≥80.0 cm. Subgroup analysis were conducted based on age (≥60 and <60 years) and whether participants met the recommended physical activity guidelines (≥75 minutes/week of vigorous physical activity or ≥150 minutes/week of moderate-intensity physical activity).

Results: A total of 3,280 Hong Kong Chinese women aged 56.46±8.30 years were included. The overall prevalence of central obesity was 32.26% (1,058 of 3,280). Participants with central obesity had a longer sitting time compared to those without (8.01±3.27 vs. 7.60±3.25 hours/day, P=0.001). After adjusting for age, education, living alone or with family members, drink, smoking, and physical activity, each additional hour of daily sitting time was significantly correlated with 0.678 unit increase in hip circumference (P<0.001), 0.003 unit increase in WHR (P=0.004), 0.004 unit increase in WHtR (P=0.002), and 5.485 unit increase in trunk body fat percentage (P<0.001). With a one-unit augment in sitting time, the odds of being central obesity was 1.187-fold higher (95% CI=1.108-1.587, P<0.001). In subgroup analysis, the sitting time-central obesity association was significant in women aged ≥60 years (OR=1.192, 95% CI=1.085-1.309, P<0.001). Whereas, such positive association existed both in women who did not meet the physical activity guidelines (OR=1.413, 95% CI=1.011-1.977, P=0.043, 8+ vs. <8 hours/day) and those who adhered to the guidelines (OR=1.326, 95% CI=1.108-1.587, P=0.002, 8+ vs. <8 hours/day).

Conclusions: Longer sitting time exhibited a positive relationship with central obesity-related indices in terms of WC, hip circumference, trunk body fat percentage, WHR and WHtR. The significant association between sitting time and central obesity was only observed in older women, but it remained consistent and robust regardless of whether the subjects followed the recommended physical activity guidelines.