Association between body mass index and health-related physical fitness among late adolescent college students

  Objective   To explore the relationship between body mass index (BMI) and health-related physical fitness among late adolescent college students, and to provide evidence for adolescent health promotion.

  Methods  The data on 30523 first-year college students of Guangxi Normal University were collected from the National Student Physical Fitness Surveillance conducted annually from 2017 to 2021 for examining the association between body mass index (BMI) and health-related physical fitness among the students.

  Results   The mean BMI for all the students aged 18.3 ± 0.3 years was 20.46 ± 2.89 (21.51 ± 3.47 for 7407 males, 20.13 ± 2.59 for 23116 females). Of the male students, 71.8%, 9.1%, 13.3%, and 5.8% were assessed as having normal weight (BMI > 17.8 and < 24.0), underweight (BMI ≤ 17.8), overweight (BMI ≥ 24.0 and < 28.0), and obesity (BMI ≥ 28.0); of the female students, 85.8%, 7.0%, 5.8%, and 1.4% were having normal weight (BMI > 17.1 and < 24.0), underweight (BMI ≤ 17.1), overweight, and obesity; while for all the students, those proportions were 82.4%, 7.5%, 7.6%, and 2.5%, respectively. The physical fitness index (PFI) of the male students with underweight (0.006 ± 2.719), overweight (– 1.823 ± 2.995) or obesity (– 4.621 ± 3.268) were significantly lower than that of the students with normal weight (0.708 ± 2.946) (all P < 0.01); the PFI of the female students with overweight (– 1.677 ± 2.944) or obesity (– 3.787 ± 3.425) were significantly lower than that of the students with normal weight (0.177 ± 2.974) (both P < 0.01). There exists a quadratic curve relationship between PFI and BMI for the students, with the maximum PFI values of 0.845 and 0.215 corresponding to the BMI of 18.0 and 17.3 for the male and female students. The results of binary logistic regression analysis showed that compared to those with normal weight, the underweight, overweight, and obese students were at an increased risk of having low PFI, with the odds ratios (95% confidence interval) of 1.82 (1.49 – 2.22), 5.20 (4.09 – 6.61), and 16.81 (9.21 – 30.68) for the males and 1.21 (1.07 – 1.36), 3.10 (2.59 – 3.70), and 8.13 (4.76 – 13.91) , respectively.

  Conclusion  In late adolescent college students, maintaining a normal BMI is the basis for ensuring physical fitness; both underweight and overweight could exert an adverse effect on health-related physical fitness and the adverse effect of overweight and obesity are much stronger.