Independent and combined influence of the FTO rs9939609 and MC4Rrs17782313 polymorphisms on hypocaloric diet induced changes in body mass and composition and energy metabolism in non-morbid obese premenopausal women.

ABSTRACT

PURPOSE: To examine the independent and combined influence of the FTOrs9939609 and the MC4Rrs17782313 polymorphisms on changes in fat mass (FM), resting energy expenditure (REE), leptin, and thyrotropin (TSH) levels, after a 12-week energy-restricted diet intervention in non-morbid premenopausal obese women. METHODS: Fat mass (dual X-ray absorptiometry), REE (indirect calorimetry) and plasma leptin and thyrotropin levels were measured (before and after the intervention) in 77 obese (BMI 33.9 ± 2.8 kg/m(2)) women (age 36.8 ± 7.0y). RESULTS: There were no significant differences across FTOrs9939609 genotype groups (TT vs. A allele carriers, Ps>0.1) on changes in body mass (-8.6 ± 3.2% vs. -8.7 ± 3.3 %), FM (12.8 ± 4.7% vs. -12.9 ± 6.3%), REE (-11.3 ± 4.7 vs. -9.4 ± 8.1%), leptin (-34.1 ± 25.1% vs. -43.5 ± 24.1%) or TSH (5.2 ± 34.5% vs. -1.7 ± 27.1%) levels. Moreover, it was not observed any significant difference on changes in body mass (-8.6 ± 3.6% vs. -8.9 ± 2.6%), FM (-12.7 ± 6.1% vs. -13.4 ± 5.3%), REE (-9.8 ± 7.4% -9.4 ± 9.4%), leptin (-39.0 ± 26.9% vs. -44.8 ± 18.4%) or TSH (-1.0 ± 30.0% vs. 1.5 ± 26.5%) levels between non-C allele carriers and C allele carriers of the MC4Rrs17782313 (Ps>0.3). Finally, there were no significant difference on changes in body mass and composition, REE, leptin or TSH levels among non-risk allele carriers, carriers of the C allele risk of the MC4Rrs17782313, carriers of the A allele of the FTOrs9939609 and carriers of both risk alleles after the 12-week energy-restricted diet intervention (Ps>0.1). CONCLUSION: Carrying the A risk allele of the FTOrs9939609 and/or the C risk allele of the MC4Rrs17782313 did not influence body mass and FM loss, or REE decrease in obese women after a 12-week energy-restricted diet intervention.

RESUMEN

Objetivo: Examinar la influencia individual y combinada de los polimorfismos genéticos FTO rs9939609 y MC4R rs17782313 en los cambios en la masa grasa (MG), gasto energético en reposo (GER), leptina y tirotropina (TSH) tras una intervención de 12 semanas de duración con dieta hipocalórica en mujeres pre-menopáusicas con obesidad no mórbida. Métodos: Se evaluaron al inicio y al final de la intervención la MG (absorciometría dual de rayos X), el GER (calorimetría indirecta) y los niveles de leptina y TSH en sangre en 77 mujeres (edad 36.8±7.0 años) obesas (IMC 33.9±2.8kg/m2). Resultados: No se observaron diferencias estadísticamente significativas (Ps>0.1) entre las portadores y las no portadoras del alelo A del FTOrs9939609 (TT vs. portadores del alelo) en los cambios en la masa corporal (-8.6±3.2% vs. -8.7±3.3 %), MG (12.8±4.7% vs. ­12.9±6.3%), GER (-11.3±4.7 vs. -9.4±8.1%), leptina (-34.1±25.1% vs. -43.5±24.1%) y TSH (5.2±34.5% vs. -1.7±27.1%). Tampoco se observaron diferencias estadísticamente significativas en los cambios en la masa corporal (-8.6±3.6% vs. -8.9±2.6%), MG (-12.7±6.1% vs. -13.4±5.3%), GER (-9.8±7.4% -9.4±9.4%), leptina (-39.0±26.9% vs. -44.8±18.4%) y TSH (-1.0±30.0% vs. 1.5±26.5%) entre las participantes portadoras y no portadoras del alelo C del MC4Rrs17782313 (Ps>0.3). Finalmente, no se encontraron diferencias estadísticamente significativas en los cambios en la masa y composición corporal, el GER, o los niveles de leptina y TSH entre mujeres no portadoras de alelos de riesgo, portadoras del alelo C del MC4Rrs17782313, portadoras del alelo A del FTOrs9939609 y portadoras de los dos alelos de riesgo (A y C) al final de las 12 semanas de intervención con dieta hipocalórica (Ps>0.1). Conclusión: Ser portador del alelo de riesgo A del FTOrs9939609 y/o del alelo de riesgo C del MC4Rrs17782313 no influye en la pérdida de masa grasa o en el descenso del GER en mujeres obesas tras 12 semanas de intervención con dieta hipocalórica.