Associations between FTO rs9939609 polymorphism, serum vitamin D, mental health, and eating behaviors in overweight adults

ABSTRACT

Background: Despite the significant role of the Fat Mass and Obesity-Associated (FTO) gene in obesity, the underlying mechanisms are not fully elucidated. Besides, vitamin D deficiency and obesity are mostly seen together, and it can be hypothesized that this nutrient may have an impact in the role of FTO genotype in adiposity.

Objective: Thus, this study aimed to investigate the association of FTO rs9939609 gene polymorphism with eating behaviors, eating disorders, and general mental health in overweight adults, considering their vitamin D intake as a mediate confounding factor.

Methods: This cross-sectional study was carried out on 197 overweight adults in Shiraz, Iran. Genotyping was performed through amplification refractory mutation system polymerase chain reaction (ARMS PCR). Mental health, vitamin D intake, eating behaviors and disorders were assessed by the validated questionnaires.

Results: The risk allele of the FTO rs9939609 polymorphism (A) was significantly associated with a higher risk of eating behavior and mental health disorders (all P < 0.05). After considering vitamin D intake, the AA genotype carriers had significantly higher risks for poorer eating behavior (P = 0.002), mental health (P = 0.007), and general mental health (P = 0.039) compared with the TT carriers if they had insufficient vitamin D intake.

Conclusion: In conclusion, these results indicated that the A-allele of the FTO rs9939609 polymorphism may be associated with poorer eating behaviors, mental health, and higher risk of eating disorders. It was also identified that the effect of FTO rs9939609 A risk allele on eating behavior and mental health may be limited to people with insufficient vitamin D intake.

KEYWORDS:

• Fat mass and obesity-associated (FTO) gene
• vitamin D
• eating behavior
• mental health
• FTO
• overweight
• obesity
• rs9939609 polymorphism

Acknowledgments

We thank all of the Health Center’s staff for their excellent cooperation and also the participants who cooperated with the study protocol.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethics approval and consent to participate

This study has been approved by local ethics review boards at Shiraz University of Medical Sciences (ir.sums.rec.1395.100). Institutional consent forms were used in this study.

Consent for publication

All authors have read and approved the manuscript.

Authors’ contributions

MM, MHE, and FJ designed the study, and were involved in the data collection, analysis, and drafting of the manuscript. MM, MGH, and HAN were involved in the design of the study and analysis of the data, and critically reviewed the manuscript. All authors read and approved the final manuscript.

Additional information

Funding

This study was funded by Shiraz University of Medical Sciences, Shiraz, Iran [Grant number 94-01-84-11190].