PERIOD2 Variants Are Associated with Abdominal Obesity, Psycho-Behavioral Factors, and Attrition in the Dietary Treatment of Obesity

The purpose of this research was to test for association between polymorphisms in the circadian clock–related gene PERIOD2 (PER2) and attrition in patients prone to withdrawal from a behavioral weight-reduction program based on the Mediterranean diet. A total of 454 overweight/obese participants (women=380, men=74), aged 20 to 65 years, who attended outpatient clinics specializing in obesity between January and December 2008, were studied. Anthropometric, biochemical, and dietary-intake variables were analyzed. Effectiveness of the program was assessed, and a questionnaire of barriers to weight loss was considered. Multivariate analysis and logistic regression models were performed. Results indicate that PER2 polymorphisms rs2304672C>G and rs4663302C>T were associated with abdominal obesity (P<0.05). Participants who withdrew from treatment were significantly more obese and had more barriers to lose weight (P<0.05). They also displayed a lower likelihood of planning eating in advance and experiencing stress with dieting than those who completed treatment. Frequency of rs4663307 minor allele was significantly greater in withdrawers than in those who successfully completed treatment (P<0.05). Logistic regression analysis showed that rs2304672 C>G minor allele carriers had a greater probability of dropping out, displaying extreme snacking, experiencing stress with dieting, eating when bored, and skipping breakfast than noncarriers. PER2 is implicated in attrition in weight-loss treatment and may modulate eating-behavior–related phenotypes. These findings could represent a step toward personalized health care and nutrition based on a combination of genotyping and psycho-behavioral characterization.