The Role of Neck Circumference in Predicting Body Fat Distribution: A Cross-Sectional Study Among Healthy Female Medical Students

Background: Obesity, characterized by excessive fat accumulation, poses significant health risks. Traditional anthropometric measures like BMI, waist circumference (WC), and waist-to-hip ratio (WHR) are commonly used to assess obesity, but they have limitations. This study investigates neck circumference (NC) as an alternative measure for assessing body fat distribution, particularly in the context of the "thin-fat Indian" phenotype, which exhibits central obesity despite a generally lean physique. Methods: This cross-sectional study, conducted at xxx in 2023, included 63 healthy female medical students aged 18-25 years. After obtaining ethical approval and informed consent, participants underwent anthropometric measurements including NC and body fat percentage, the latter determined via bioelectrical impedance analysis (BIA). NC was measured following ISAK guidelines. Statistical analysis was performed using IBM SPSS Statistics (version 25), with Pearson's correlation coefficient and simple linear regression analysis used to explore the relationship between NC and body fat parameters. Results: The mean age of participants was 20.8±8.2 years. Mean NC was 30.03 ± 4.74 cm. The analysis revealed a strong positive correlation between NC and body fat percentage across various body sections (all r > 0.74, all p < 0.001), with the highest correlation observed for arm fat percentage (r = 0.960). Simple linear regression analysis indicated that NC significantly predicts several body fat measures, accounting for 57.9% of the variability in BMI, 68.7% in total body fat percentage, 79.3% in subcutaneous fat percentage, 55.7% in visceral fat percentage, 92.2% in arm fat percentage, 88.9% in trunk fat percentage, and 87.1% in leg fat percentage. Conclusion: The findings suggest that NC is a robust predictor of body fat distribution, particularly for arm and trunk fat percentages. This aligns with previous research highlighting NC as a valuable tool for identifying obesity-related health risks. The strong correlations and high coefficients of determination underscore the potential of NC as a simple, non-invasive, and cost-effective method for assessing body fat composition, especially in community settings.