Impact Of The Covid-19 Pandemic Lockdown On BMI: A Three-year Follow Up Study In 6156 Chinese College Students

Purpose: This study aims to assess the influence of the lockdown measures implemented during the COVID-19 pandemic on Chinese college students’ Body Mass Index (BMI) through a three-year cohort study. Methods: We recruited 6122 college students (4,226 male & 1,896 female, age 18.67 ± 0.86 yr.) from a University in China to participate in this three-year cohort study. All of the subjects took the same physical fitness tests from 2019 to 2021 (pre-lockdown, during lockdown and post-lockdown). Participants’ height and weight data were objectively measured by Tongfang Health Fitness Testing Products 5000 series. A paired t-test was performed in the analysis. Results: During the lockdown, there is 4.2% increase of BMI among the college student (p < 0.001). Moreover, males had a greater overall mean BMI rate increase of 4.74% (p < 0.001) than females (2.86%, p < 0.001). After the lockdown, there is 0.94% increase of BMI among the college student (p < 0.001). However, females had a greater overall mean BMI rate increase of 1.49% (p < 0.001) than males (0.72%, p < 0.001). During this period, the obese and overweight group’s growth rate from 2019 to 2020 was smaller than the normal and underweight group, which were 2.94% (p < 0.001), 3.90% (p < 0.001), 4.44% (p < 0.001) and 5.25% (p < 0.001), respectively. Conclusion: BMI increased both during and post-pandemic periods among Chinese college students. However, participants with higher BMI groups appeared to have a diminished BMI growth rate. After the lockdown, participants with higher BMI levels appeared to have an augmented BMI growth rate. Public policy action is needed to increase the level of physical activity of Chinese college students and take action to improve students’ physical fitness performance after the lockdown Table 3 - The paired t-test results of the participants’ BMI from 2019 to 2020 2020-2019 Underweight Normal Overweight Obese Total Paired differ-ence mean(95% CI ) Change(%) Effect size(95% CI) t Paired differ-ence mean(95% CI ) Change(%) Effect size(95% CI) t Paired differ-ence mean(95% CI ) Change(%) Effect size(95% CI) t Paired differ-ence mean(95% CI ) Change (%) Effect size(95% CI) t Paired differ-ence mean(95% CI ) Change (%) Effect size(95% CI) t Male 1.04(0.96,1.11) 5.92%↑ 1.11(1.00,1.20) 26.57*** 1.10(1.06,1.15) 5.30%↑ 0.97(0.92,1.02) 46.43*** 1.07(0.96,1.19) 4.50%↑ 0.72(0.63,0.80) 18.81*** 0.82(0.66,0.98) 2.95%↑ 0.39(0.31,0.47) 10.27*** 1.04(1.00,1.08) 4.74%↑ 0.75(0.72,0.79) 49.17*** Fe-male 0.76(0.68,0.85) 4.35%↑ 0.88(0.77,0.99) 18.19*** 0.57(0.51,0.63) 2.78%↑ 0.51(0.45,0.57) 17.75*** 0.31(0.07,0.55) 1.28%↑ 0.20(0.04,0.36) 2.51* 0.78(0.39,1.17) 2.86%↑ 0.38(0.18,0.58) 3.93*** 0.60(0.55,0.66) 2.95%↑ 0.51(0.46,0.56) 22.25*** Total 0.92(0.86,0.98) 5.25%↑ 1.00(0.93,1.08) 31.78*** 0.92(0.88,0.96) 4.44%↑ 0.79(0.75,0.83) 46.92*** 0.93(0.83,1.04) 3.90%↑ 0.61(0.54,0.68) 17.68*** 0.82(0.67,0.96) 2.94%↑ 0.39(0.32,0.46) 11.00*** 0.91(0.87,0.94) 4.21%↑ 0.68(0.65,0.70) 53.10***