The effect of genetic background on blood pressure response to weight reduction

INTERVENTION: Overweight men aged between 20 and 70 yrs and post‐menopausal women less than 70yrs will be screened for two genetic polymorphisms called CYP4F2 G1347A and CYP4A11 T8590C that affect 20‐HETE levels. The screening visit will take approximately 1 hour and requires donation of a small blood sample (10ml). Genetic material (DNA) will be isolated from this blood sample in for identification of the two polymorphisms. Two groups will be studied. A group that are carriers of the A allele of the CYP4F2 G1347A polymorphism but who do not have the CYP4A11 T8590C polymorphism and a control group that has neither polymorphism. Both groups will receive one on one 1 hour sessions with a dietitian every 2 weeks to assist them to reduced their weight (by 4‐8kg) over a 12 week period. At the end of 12 weeks, volunteers will be counselled every 2 weeks by the dietitain about how to maintain their weight for a 4 week period of weight stabilisation. CONDITION: metabolic syndrome PRIMARY OUTCOME: Blood pressure using a 24 hor ambulatory blood pressure monitor Plasma 20‐HETE measured by gas chromatography mass spectrometry Urinary 20‐HETE measured from a 24 hour urine collection by gas chromatography mass spectrometry SECONDARY OUTCOME: Urinary F2‐isoprostanes measured in a 24hr urine collection by gas chromatography mass spectrometry plasma F2‐isoprostanes measured by gas chromatography mass spectrometry INCLUSION CRITERIA: Volunteers will undergo a medical examination conducted by a physician to assess their suitability for the study. Overweight men with waist circumference greater than or equal to 102cm and overweight post‐menopausal women with with waist circumference greater than or equal to 88cm who have a systolic blood pressure greater or equal to 120mmHg and body mass index between 25 and 40. They will be screened for two genetic polymorphisms called CYP4F2 G1347A and CYP4A11 T8590C that affect 20‐HETE levels. Two groups will be studied. A group that are carriers of the A allele of the CYP4F2 G1347A polymorphism but who do not have the CYP4A11 T8590C polymorphism and a control group that has neither polymorphism.