Association between subjective body image, body mass index and psychological symptoms in chinese adolescents: A nationwide cross-sectional study

Background: Conflicting findings were reported about the associations between subjective body image (SBI), body mass index (BMI) and psychological symptoms in China and other countries in the world. In this study, we aim to explore the associations between SBI, BMI, and psychological symptoms based on a large-scale, national wide survey among Chinese adolescents. Methods: The 2014–2015 China Education Panel Survey (CEPS) database, with 8134 middle school students (4137 boys and 3997 girls), was analyzed to explore the association between SBI, BMI and psychological symptoms. SBI was assessed by one question about the perception of own body shape with options “very thin”, “slightly thin”, “average”, “weak heavy”, and “very heavy”. BMI was calculated by the self-reported body weight and height. Psychological symptoms were evaluated by 10 items involving both aspects of depression and anxiety. Results: The results indicated that both boys and girls who perceived weak or very heavy weight were positively associated with psychological symptoms (p < 0.05). For boys, perceiving very thin body image was also in higher risk of psychological symptoms (p < 0.05), after controlling social-demographic variables and BMI. Comparing with normal weight boys or girls, obese boys (β = −2.22, 95% CI −3.37~−1.07) and overweight girls (β = −1.03, 95% CI −2.01~−0.06) were in lower levels of psychological symptoms after controlling for SBI. Other factors associated with psychological symptoms were family economic status, academic performance, and self-rated health status. Conclusions: A deviation from an “average” SBI was positively associated with psychological symptoms, which should be scanned when evaluating the Chinese adolescents’ mental health. These findings provide epidemiological evidence for the association between SBI and psychological symptoms in non-western social contexts.