Somatization and Body Composition: Findings from a Cross-Sectional Study on Non-Clinical Young Adults

Lifestyle is a significant, common, and easily modifiable factor capable of increasing or reducing the risk of acquiring many diseases. Currently, there is a research gap as too little scientific attention has been focused on exploring the relationship between mental health and nutritional status in various populations. Moreover, the association between body composition and somatization has not been fully disclosed. Therefore, this study aimed to assess the associations of body composition with the symptomatology of somatization in an environmentally vulnerable sample of young adults.

A single cross-sectional study included young non-clinical Lithuanian students (n = 1223) aged 21.7 ± 3.9. The body adiposity status of the study participants was estimated using both the body mass index (BMI) and the Body Adiposity Estimator (CUN-BAE) method. Fat-free mass was evaluated via the adjusted fat-free mass index equation (FFMI_adj). The Patient Health Questionnaire (PHQ-15) was applied to assess the severity of the perceived symptoms of a somatic symptom disorder (SSD).

The CUN-BAE was considered to be a better predictor of adiposity than the BMI because 14.7% of females and 6.2% of males were interpreted as obese using the CUN-BAE, while the BMI equation identified participants as having a normal body weight. The highest rates of somatization were found in 18.6% of the cohort. Young adults with higher amounts of body fat mass (β: 0.050, 95% confidence interval (95% CI): 0.013; 0.084, p = 0.007) and lower FFMI are prone to a higher risk for developing somatization (β: -0.429, 95% CI: -0.597; -0.260, p < 0.001).

Our study revealed that body composition is significantly related to multiple somatic complaints throughout a range of measurements. However, in contrast to the CUN-BAE tool, the BMI equation underestimated the relationship between body fat and mental health outcomes in young adults. Even though nutritional status along with targeted physical load, as the mediators, are likely to play a significant role in the maintenance of optimal body composition and mental health outcomes, healthcare providers are recommended to advise individuals to lower their body fat percentage and increase fat-free mass in order to reduce the risk of somatization.